CatalogIntroductionⅠ What is a Microcontroller（MCU）?Ⅱ The History of the Microcontroller (MCU)Ⅲ The Classification and Application of MCUⅣ China MCU Technology and Well-known ManufacturersⅤ  The Basic Functions of MCUⅥ Learning Methods - Using MCUⅦ Six Main Dimensions of MCU Products for Future ImprovementⅧ Programming of MCUⅨ Summary of the MCU Programming EngineerⅩ How to Develop MCU Ⅺ 5 Tips to Solve the Questions About the MCU CrystalⅫ Summary of Chip OperationFAQIntroductionA microcontroller (MCU) is a small computer built on a single metal-oxide-semiconductor (MOS) integrated circuit (IC) chip. A microcontroller is made up of a CPU  (processor core), memory, and programmable input/output peripherals. On chip, a small amount of RAM, as well as ferroelectric RAM, NOR flash, or OTP ROM , is commonly included. Microcontrollers  , in contrast to microprocessors  used in personal computers  or other general-purpose applications, are designed for embedded applications and are made up of a number of discrete chips. This article will delve deeper into the MCU.Ⅰ What is a Microcontroller（MCU）? Microcontroller UnitThe microcontroller unit (MCU) appropriately reduces the frequency and specifications of the CPU  and integrates peripheral interfaces such as memory, counter, USB, A/D conversion, UART, PLC, and DMA. At the same time, even the LCD driver circuit is integrated on a single chip to form a chip-level computer, which can be controlled in different combinations for different applications, such as mobile phones, PC peripherals, remote controls, automotive electronics, industrial stepping motors, machines The control of the arm, etc., can be seen in the MCU.Figure 1 MCU componentsⅡ The History of the Microcontroller (MCU)Microcontroller Unit has a short history, but it has evolved quickly. Its generation and development are roughly synchronized with that of microprocessors  (CPUs). Since Intel Corporation of the United States first introduced 4-bit microprocessors  in 1971, its evolution can be roughly divided into five stages. The following is an overview of the development of Intel's MCU.1971-1976  The initial stage of MCU developmentIn November 1971, Intel introduced the Intel 4004, a 4-bit microprocessor with an integration level of 2000 transistors/chips and equipped with RAM, ROM, and shift registers, which served as the first MCS-4 microprocessor. The Intel 8008 8-bit microprocessor was introduced, followed by other 8-bit microprocessors  from various companies.1976-1980  Low-performance MCU stageThe MCS-48 series, introduced by Intel Corporation in 1976, has a monolithic structure that integrates an 8-bit CPU.  an 8-bit parallel I/O interface, an 8-bit timer/counter, RAM, and ROM on a semiconductor chip. Its addressing range is limited (no more than 4 KB), there is no serial I/O, the RAM and ROM capacity is limited, and the interrupt system is simple, but its functions can meet the needs of general industrial control and intelligent instruments and meters.1980~1983  High-performance MCU stageHigh-performance 8-bit microcontrollers introduced at this stage typically include serial ports, multi-level interrupt processing systems, and multiple 16-bit timers/counters. The capacity of the on-chip RAM and ROM  is increased, and the addressing range can reach 64 KB. A/D conversion interfaces are also available on individual chips. 1983~late 1980s  16-bit microcontroller stage.In 1983, Intel introduced a high-performance 16-bit microcontroller MCS-96  series. The chip integration level was as high as 120,000 transistors/chips due to the use of the most recent manufacturing process.1990sCPUs are developing to a higher level in all directions, such as integration, function, speed, reliability, and application fields. Ⅲ The Classification and Application of MCUMCUs are classified into two types based on their memory type: those with no on-chip ROM  and those with on-chip ROM,  The chip without on-chip ROM  must be used externally with EPROM (typically 8031); the chip with on-chip ROM  is classified as on-chip EPROM (typically 87C51), MASK on-chip mask ROM  (typically 8051), on-chip Flash (typically 89C51), and other types.MCUs are classified into two types based on their intended use: general-purpose and special-purpose. It is classified into4, 8, 16, and 32-bit MCUs based on the width of the data bus and the number of data bytes that can be processed at the same time.Figure 2 MCU product category At present, the most widely used MCU market in China is in the consumer electronics  field, followed by the industrial field and the automotive electronics  market. Consumer electronics  include home appliances, televisions, game consoles, and audio and video systems. Industrial fields include smart homes, automation, medical applications, and new energy generation and distribution. The automotive field includes automotive powertrains and safety control systems. Industrial MCU Industrial MCU products  are primarily used for motor control operation, data acquisition control, and other functions in motor control, instrumentation, low-voltage power distribution, power tools, industrial robots, and other application scenarios.Figure 3 Electric-Vehicle-ChargerThe number of MCU devices is increasing as the complexity of industrial equipment increases. Consider industrial robots: at least ten MCU products  are used in a single industrial robot.Home Appliance MCU MCU is widely used in household appliances, mainly used to realize system control, motor control, panel display control, and other functions.The home appliance market is mainly divided into small household appliances and everyone electricity, small household appliances including kitchen appliances (microwave oven, induction cooker, soybean milk machine, etc.), household appliances (vacuum cleaner, electric fan, electric heater, etc.), personal life small household appliances (electric toothbrush, hairdryer, etc.), everyone electricity mainly for air conditioning, refrigerator, washing machine, and other white appliances.Figure 4 Induction-heating-cooker-app-block-diagramAt the moment, 32-bit MCUs have become the market's mainstream due to their higher specifications and performance, as well as their constantly decreasing cost, and are widely used in automotive electronics.  industrial control/medical, and other fields; however, there are still a large number of application scenarios requiring simple control, and low-value MCUs have cost advantages, so they continue to occupy a large market.BitApplication4Calculator, auto instrument, auto anti-theft device, pager, wireless phone, CD player, LCD dynamic controller, children's toys, scales, chargers, Tire gauge, thermometer, remote control, etc8Electrical appliances, ammeter, motor controller, electric toy machine, pager, fax machine, telephonograph, keyboard and USB, etc16Mobile phones, digital cameras and video recorders, etc32Smart home, IoT, motor and frequency conversion control, security monitoring, fingerprint identification, touch keys, Modem, GPS, STB, Workstation, ISDN telephone, laser printer and color fax machine, etc64Advanced workstation, multimedia interactive system, advanced TV game instrument, advanced terminal, etc.According to IC Insights, the global MCU market is about 16.4 billion dollars in 2019 and could reach about 20 billion dollars by 2023.The scale of China's MCU market was about 25.6 billion yuan in 2019, accounting for about 26% of the global market, with a compound growth rate of 9% from 2015 to 2019.In terms of the global market, the auto circuit accounts for 33% of the global MCU market. According to IC Insights data, the automotive MCU market space will reach $8.1 billion in 2023, the overall growth rate is considerable; At the moment, 32-bit MCUs have become the market's mainstream due to their higher specifications and performance, as well as their constantly decreasing cost, and are widely used in automotive electronics.  industrial control/medical, and other fields; however, there are still a large number of application scenarios requiring simple control, and low-value MCUs have cost advantages, so they continue to occupy a large market.Figure 5  MCU Market StructureFrom the perspective of pattern, the top five global automotive MCU market shares in 2020 were Renesas, NXP, Infineon, Texas Instruments and Microchip, accounting for 87% in total.Ⅳ China MCU Technology and Well-known ManufacturersMCU market is still dominated by overseas leaders, and Chinese high-quality manufacturers are gradually making breakthroughs in the segmented fields, and their share is expected to increase rapidly under the background of accelerated localization in China.The global MCU market is expected to grow further, with the global MCU market size reaching $16.4 billion in 2019 and $20 billion in 2023.On the demand side, improvements in automotive electrification, accelerated IoT  penetration, increased demand for intelligent frequency conversion in home appliances, rapid iteration of wearable devices, and steady growth in industrial control continue to drive the rapid growth of the MCU industry. (Using MCU as an example, the global market compound growth rate from 2020 to 2023 is 7.7 percent, and the market space is expected to be 8.1 billion dollars by 2023)On the supply side, the MCU industry is experiencing a continuous shortage due to the epidemic in 2020. Infineon, NXP.  and ST  , as well as other overseas MCU large factories, have appeared several times to dozens of times the price, with delivery times of more than 50 weeks; persistent shortages are expected to last at least through the end of 2021 and the first quarter of 2022.In terms of circuit barriers, the requirements of automobile circuits in the MCU downstream field are the highest, followed by industrial and home appliance circuits, and the relative requirements of consumer electronics  are slightly lower, according to MCU product environmental temperature, yield, and service life, and other parameters.According to the industry competition pattern, Chinese MCU manufacturers have a low market share, benefit from accelerated replacement due to stock shortages in the short term, and have ample room for improvement in the long term:The global MCU market is more concentrated, with a microchip, ST  MICROELECTRONICS, Renesas, TI, NXP  , Infineon, and other manufacturers occupying more than 80% of the market share; China's MCU market is approximately 25 billion yuan, and the total market share of domestic MCU manufacturers is less than 12%, primarily concentrated in the consumer market, which has ample room for expansion.The shortage of goods leads to the acceleration of the pace of China's MCU manufacturers, in the automotive, industrial, and consumer circuit, the pace of China's MCU certification continues to accelerate. Renesas Electronics - the world's first automotive MCU manufacturer Renesas was founded in 2003 by the merger of Hitachi Semiconductor division and Mitsubishi Electric Semiconductor division. Its main business covers automotive, industrial, communications, and other fields. Renesas is the world's first automotive MCU manufacturer, accounting for 30% of the automotive MCU market in 2020.Renesas MCU has a complete product line covering EV/HEV, powertrain, electric vehicle, vehicle dashboard, vehicle network, chassis control, ADAS, and other application fields.Microchip technology -8 bit MCU main features, acquisition of Atmel to supplement the strength of 32 bit MCUMicrochip Technology Corporation (Microchip) was founded in 1989, Microchip technology is the world's leading supplier of single-chip and analog semiconductors. The company's main business is the microcontroller, memory products, analog interface, and mixed information products, technology licensing, and so on.The products are mainly used in embedded control systems and IoT-related industries, including data processing, Medical Internet + (IoT), smart city, Industry 4.0, intelligent healthcare, etc. Major customers include Intel, Dell, Lockheed Martin, HP, Boeing, etc. STST -ARM architecture MCU king ST was founded in 1987, its products are mainly used in automotive products, computer peripherals, communication systems, consumer products, industrial automation control systems, and other aspects. Its major customers include Apple, blackberry, Bosch, Cisco, Conti, HP, Nokia, Obata, Samsung, and Western Digital.MCU vehicle grade products accounted for 32.13% of the company's revenue. St holds 8.5% of the current MCU market and is the leader in the segmented 32bitMCU  market.ST has been deeply engaged in the automotive semiconductor field for many years, and the company has a complete industrial chain, its products have a very high-cost performance ratio, and occupy a dominant position in the MCU of vehicle regulation level. Its customers include Nissan, Audi, SAIC, Tesla, and many other companies. NXP - the world's leading automotive MCU manufacturer NXP Semiconductor was founded in 2006. It was formerly the semiconductor division of Philips. NXP's main business is MCU, MPU, and other products, which can be widely used in automotive electronics  , industrial control, smart city, smart home, and wearable products. Its MCU/MPU based on the S32 automotive platform has obvious advantages in safety and efficiency and has been adopted by mainstream OEMs around the world.The industry's first crossover MCU was independently developed by NXP: I. MX RT series. Such products have been recognized by many Internet platforms (such as Amazon) for their high integration, cost performance, and security.NXP's acquisition of Freescale (founded by MOTOROLA) in 2015 gives it a deeper presence in the automotive industry. In 2020, 47% of its revenue came from vehicle MCU. At present, the company accounts for 27.8% of the global automotive MCU industry, ranking second in the world. NXP  provides complete semiconductor solutions for intelligent vehicles including automotive entertainment systems, Advanced Driver Assistance Systems (ADAS). Sino Wealth Electronics - China's largest home appliance MCU manufacturer Sino Wealth Electronic Ltd. is an MCU integrated circuit design company, the main products include 8-bit Flash MCU, 8-bit OTP/Mask MCU, 16-bit  DSP , 4-bit OTP/Mask MCU, widely used in household appliances, automotive, industrial control, security, and other fields;In the field of small household appliances, the company's competitors are mainly ABOV from Korea and Holtek from Taiwan. In the field of white household appliances, the company's competitors are mainly from Europe and America, including Renesas, NEC, TI, STM, and so on. Ⅴ The Basic Functions of MCUInternal-function diagramFor most MCUs, the following functions are the most common and basic. The description methods for different MCUs may differ, but the essence is essentially the same.1. Timer: Although there are many different types of Timers, they can be divided into two categories. The first is a Timer with a fixed time interval, which means that its timing is set by the system and cannot be controlled by the user program. The system only provides a few different types of Timers. The user program is given a fixed time interval, such as 32Hz, 16Hz, 8Hz, and so on. Because Timers of this type are relatively common in 4-bit MCUs,they can be used to implement clock, timing, and other related functions.The other type is Programmable Timer. The timing of this type of Timer can be controlled by the user's program. The control methods include the selection of the clock source, the selection of the prescale number, and the setting of the preset number, etc. There are Most MCUs have all three at the same time, and some may have one or both of them. This kind of Timer application is very flexible, and the actual use is also ever-changing. One of the most common applications is to use it to achieve PWM  output.Since the clock source can be freely selected, such Timers are generally combined with the Event Counter.2. IO port: Any MCU has a certain number of IO ports. Without IO ports, the MCU will lose the channel of communication with the outside world. According to the configurable situation of the IO port, it can be divided into the following types:Pure input or pure output : This type of IO port is determined by the MCU hardware design, and can only be input or output, and cannot be set in real-time by software.3. Directly read and write IO port: For example, the IO port of MCS-51 belongs to this type of IO port. When the read IO port command is executed, it is an input port; when the write IO port command is executed, it is automatically an output port.Program programming to set the direction of input and output: the input or output of this type of IO port is set by the program according to the actual needs, the application is more flexible, and can realize some bus-level applications, such as12C bus, various LCD, LED Driver control bus, etc.When using the IO port, this point must be kept in mind: for the input port, there must be a clear level signal to ensure that it cannot be floated (this can be achieved by adding a pull-up or pull-down resistor); and for the output port, the output state level must be Considering its external connection, it should be ensured that there is no source current or sink current in Standby or static state.External interrupts: External interrupts are a basic function of most MCUs. They are commonly used for real-time signal generation, data sampling, and state detection. Rising edge, falling edge, and level triggering are all interrupting methods. In most cases, the external interrupt is handled via the input port. If it is an IO port, the interrupt function will only be enabled when it is set as an input port; if it is set as an output port, the external interrupt function will be automatically closed (with some exceptions in ATMEL's ATiny series, where the output port can also trigger the interrupt function). The application of external interrupt is as follows:Detection of external trigger signals: One is based on real-time requirements, such as thyristor control, detection of sudden signals, and so on, while the other is based on power savings.Measurement of signal frequency:: To ensure that the signal is not missed, an external interrupt is the best option.Decoding data: To reduce design costs in the field of remote control applications, it is frequently necessary to use software to decode various encoded data, such as Manchester and PWM encoding.Button detection and system wake-up: In order for the MCU to enter the Sleep state, it must be woken up via an external interrupt. The most basic form is a button, and the level change is caused by the button's action.4. Communication interface: The communication interface provided by MCU generally includes SPI interface, UART. I2C interface, etc., which are described as follows:SPI interface: This type of interface is the most basic communication method provided by most MCUs. Its data transmission is controlled by a synchronous clock. The signals include SDI (serial data input), SDO (serial data output), SCLK (serial clock), and Ready signal; in some cases, there may be no Ready signal; this type of interface can work in Master mode or Slave mode, the popular saying is to see who provides the clock signal, the party providing the clock is the Master, and the opposite party It is Slaver.UART（Universal Asynchronous Receive Transmit）：It belongs to the most basic asynchronous transmission interface. Its signal lines only have two Rx and Tx lines. The basic data format is: Start Bit + Data Bit(7-bits/8-bits) + Parity Bit(Even， Odd or None) + Stop Bit(1~2Bit). The time occupied by one bit of data is called Baud Rate .For most MCUs, the length of data bits, data check mode (odd check, even check or no check), Stop Bit length and Baud Rate can be flexibly set through program programming. Certainly. The most common way of this type of interface is to communicate with the serial port of the PC.I2C interface: I2C  is a data transmission protocol developed by Philips. It also uses two signals to implement: SDAT (serial data input and output) and SCLK (serial clock). The biggest advantage is that multiple devices can be attached to this bus, and they can be identified and accessed through addresses; one of the biggest advantages of the I2C  bus is that it is very convenient to use software to implement through the IO port, and the data rate of its transmission is completely controlled by SCLK. To control, it can be fast or slow, unlike the UART  interface, which has strict rate requirements.5. Watchdog: Watchdoga basic configuration of most MCUs, can only allow the program to reset it but not close it (some are set when the program is burned in, such as Microchip PIC  series MCUs), while some MCUs are It is determined by a specific method whether it is turned on or not. For example, in Samsung's KS57 series, as long as the program accesses the Watchdog  register, it is automatically turned on and cannot be turned off again. Generally speaking, the reset time of the watchdog can be set by the program. The most basic application of Watchdog  is to provide a self-recovery ability for the MCU to crash due to unexpected failure.Ⅵ Learning Methods - Using MCUThe basic principles and functions of any MCU are similar. The only difference is the configuration and quantity of its peripheral function modules and the instruction system.For the instruction system, although it seems to be different in form, it is only a difference in symbols, and the meanings it represents, the functions to be completed, and the addressing modes are similar.To learn about an MCU, the first thing you need to know is its ROM space, RAM space, number of IO ports, number of timers and timing methods, peripheral function modules (Peripheral Circuit) provided, interrupt sources, operating voltage, and power consumption, etc.After understanding these MCU Features, the next step is to compare the functions of the selected MCU with the required functions of the actual project development and clarify which resources are currently required and which are not used in this project.For the functions that need to be used in the project but are not provided by the selected MCU, it is necessary to carefully understand the relevant information of the MCU, to use an indirect method to achieve it. For example, the developed project needs to communicate with the COM port of the PC, and If the selected MCU does not provide a UART  port, it can be implemented through external interrupts.For the resources needed for project development, you need to carefully understand and read the Manua*, while for the unneeded function modules, you can ignore or browse. For MCU learning, the application is the key and the main purpose.For beginners or designers who use this MCU for the first time, they may encounter a lot of ambiguous descriptions of the functions of the MCU. For this kind of problem, there are two ways to solve it, one is to write a special verification program to understand the functions described in the data; the other can be ignored for the time being. Leave it to modify and improve when debugging. The former method is suitable for projects with loose time and beginners, while the latter method is suitable for those who have some experience in single-chip development or when the project schedule is more urgent.Don't take the time to learn the command system in particular. The instruction system is simply a logical description symbol. During programming, you can only check the relevant instructions in accordance with the logic requirements of the program. As your programming skills improve, you will become more proficient in the instruction system.Ⅶ Six Main Dimensions of MCU Products for Future ImprovementStronger computing performance: MCU towards 500Mhz main frequency, MPU increase more processor cores;Additional wireless connection functions: More RF modules have been integrated.Low power consumption, high energy efficiency ratio: integrated analog chip, and low power analog peripheralsContinued support for hardware accelerators: high integration of algorithms and toolsSafety: improve anti-interference ability and safetyCost-effective: reduce costⅧ Programming of MCUThe programming of MCUs and PCs differ significantly. Although C-based MCU development tools are becoming more popular, assembly language remains the most concise and efficient programming language for designers who are efficient program code and like to use assembly.Circuit diagram to build your own microcontroller programmerThe basic framework for MCU programming is roughly the same, divided into the initialization part (the biggest difference between MCU programming and PC programming), the main program loop body, and the interrupt handler. as shown below:1.Initialization: The most basic and important step in the design of all MCU programs is an initialization, which generally includes the following:Mask all interrupts and set the stack pointer to In general, the initialization section does not want any interruptions to occur.Clearing the system's RAM and displaying the Memory: Although it is not always necessary, it is recommended to develop good programming habits for the sake of reliability and consistency, particularly to avoid accidental errors.IO port initialization: Set the input and output modes of the relevant IO port based on the project's application requirements. Set the pull-up or pull-down resistance for the input port, and the initial resistance for the output port.Interrupt setup: Enable and set interrupt trigger conditions for all interrupt sources required by the project, and close unnecessary interrupts that are not used.Initialization of other functional modules: For all peripheral functional modules of MCU that need to be used, corresponding Settings must be carried out according to the application requirements of the project. For example, Baud Rate, data length, verification mode and Stop Bit length should be set for communication of UART  , and clock source should be set for Programmer Timer. Frequency and Reload Data, etc.Initialization of parameters: after completing the initialization of MCU hardware and resources, the following is the initialization of some variables and data used in the program. This part of initialization needs to be designed according to the specific project and the overall arrangement of the program. For some applications that use EEPROM to store the number of prefab items, it is recommended to copy the relevant data to THE RAM of MCU during initialization to improve the speed of data access and reduce the power consumption of the system (in principle, access to the external EEPROM will increase the power consumption of the power supply).2.Main program loop body: Most MCUs run continuously for a long time, so their main program bodies are basically designed in a looping manner. For applications with multiple working modes, there may be many Each loop body is converted between each other through state flags. For the main program body, the following modules are generally arranged:Calculation procedures: Calculation procedures are generally time-consuming, so it is strongly opposed to processing in any interrupt, especially multiplication and division operations.Processing programs with low or no real-time requirements;Display transfer program: mainly for applications with external LED and LCD Driver.3. Interrupt handler: The interrupt program is mainly used to handle tasks and events with high real-time requirements, such as detection of external sudden signals, detection, and processing of buttons, timing counting, LED display scanning, etc.Under normal circumstances, the interrupt program should keep the code as concise as possible. For functions that do not need to be processed in real-time, the trigger flag can be set in the interrupt, and then the main program executes the specific transaction - this is very important, especially for low-power, low-speed MCUs, is necessary to ensure timely responses to all interrupts.4. There are various MCU processing methods for various task bodies.For example, for low-speed, low-power MCU (Fosc=32768Hz) applications, considering that such projects are handheld devices and use ordinary LCD, the response to buttons and display response requires high real-time performance, so generally Timed interrupts are used to process button actions and data display; for high-speed MCUs, such as Fosc>1MHz applications, since the MCU has enough time to execute the main program loop body at this time, it can only be interrupted at the corresponding Various trigger flags are set in the program, and all tasks are executed in the main program body.5. In MCU programming, special attention should be paid to:Avoid situations where the same variable or data is accessed or set in both the interrupt and the main body. The effective prevention method is to arrange the processing of such data in a module, and decide whether to execute the relevant operation of the data by judging the trigger flag; In other bodies (mainly interrupts), only the trigger flag is set where the processing of the data is required. This ensures that data execution is predictable and unique.Ⅸ Summary of the MCU Programming EngineerTo develop a good habit of summarizing, summarizing is not only a summary of their learning, but also a review and deepening of the learning process, but also to avoid the second error.Before writing the program, we should have a solid understanding of the project so that we can start with a solid idea and a general framework. It is critical to consider the layout and what makes the most sense. To determine which module should be completed first, specific steps for the module, how to name each function, and the relationship with other modules. Take a piece of paper and scribble down significant progress.For C language modular programming, we should first divide each module, a module programming, determine a sequence, and then write the next module based on the success of the previous one. When it comes to header files, write the module's header file after you've finished writing the module.Do not ignore the fact that the program must be unreasonable to comprehend its origins and find a solution. When looking for a source, it should be pertinent; you can search for relevant data on the Internet or consult with others. For example, the primary function of another project was incorporated into this project. Some functions are named multiple times. Step by step analysis of the cause, also according to the experimental phenomenon. When defining the port, the incorrect interface was selected. When you can't solve a problem, it's sometimes good to take a break. Things can go wrong no matter how simple they seemThe problems of code utilization efficiency, anti-interference, and MCU reliability continue to plague MCU application development. Ⅹ How to Develop MCU 1How to reduce program bugsThe following are the over-arching management parameters that should be considered during system operation in order to reduce program bugs.Physical parameters: These are primarily system input parameters that include excitation parameters, acquisition and processing operating parameters, and result parameters at the end of processing.Resource parameters: These are primarily the resources of the system's circuits, devices, and functional units, such as memory capacity, storage unit length, and stacking depth.These application parameters are frequently expressed as the application conditions of some single-chip microcomputers and functional units. The term "process parameter" refers to a parameter that changes in an orderly manner during the system's operation.2How to improve the efficiency of C language programming codeIt is an inevitable trend of the development and application of MCU to use C language to design MCU. If you are programming in C, it is best to be familiar with the C compiler you are using to achieve maximum efficiency. First test the number of statement lines in the assembly language corresponding to each C language compilation, so that you can clearly know the efficiency. When programming in the future, use the statement with the highest compilation efficiency. Each C compiler will have certain differences, so the compilation efficiency will also be different. The code length and execution time of an excellent embedded system C compiler is only 5-20% longer than the same functional degree written in assembly language.C language can be used for complex and time-critical projects, but the premise is that you are very familiar with the C language and C compiler of the MCU system and that you pay special attention to the data types and algorithms that the C compiler system can support. Although C is the most commonly used high-level language, the C language compilation system varies due to MCU manufacturer differences, particularly in the operation of some special function modules. As a result, if you don't understand these features, you'll have a lot of trouble debugging, which will result in lower execution efficiency than assembly language.3 How to Solve the MCU Anti-Interference ProblemThe most effective way to prevent interference is to remove interference sources and cut off interference paths, but this is often difficult to do, so we can only conclude that MCU's anti-interference ability is insufficient. While improving the anti-interference capability of hardware systems, software anti-interference has received increasing attention due to its flexible design, ability to save hardware resources, and high reliability.As for the program run fly, in fact, can also use software trap and watchdog to pull the program back to reset state, so the MCU software anti-interference is the most important to deal with the reset state.In most cases, MCU will have some sign registers that can be used to determine the reason for the reset; alternatively, you can bury some tokens in RAM yourself. Different reset causes can be determined in each program reset by judging these signs. You can also use different flags to jump directly to the corresponding program. In this manner, the program will run indefinitely, and the user will be unaware that it has been reset.4How to test the reliability of the MCU systemWhen a MCU system design is completed, there will be different test items and methods for different MCU system products, but some must be tested:lTest the completeness of the software functions of the MCUlPower-on and power-off testlAging testlTests such as ESD and EFT Sometimes, we can also simulate the damage that may occur in human use. For example, the contact port of the MCU system is intentionally rubbed with the human body or clothing fabric, thereby testing the antistatic ability. Use a high-power electric drill to work close to the MCU system to test the anti-electromagnetic interference ability.To sum up, the MCU has become an important aspect of the development and application of the computer.Most of the functions that must be realized by analog circuits or digital circuits in the past can now be realized by software methods using a single-chip microcomputer. This control technology in which software replaces hardware is also called micro-control technology, which is a revolution of traditional control technology.In addition, in the process of development and application, we must master the skills and improve the efficiency, so as to facilitate its wider use.Ⅺ 5 Tips to Solve the Questions About the MCU CrystalCrystal oscillator for MCUCommon causes of the crystal can not vibratePCB wiring error;Microcontroller quality issues;Crystal vibration quality issues;The load capacitance or matching capacitance does not match the crystal oscillator or the capacitor quality is incorrect;PCB board damp, resulting in impedance mismatch and inability to vibrate;The crystal oscillator circuit is too long;There is a line between the feet of crystal;Influence of peripheral circuit.You are advised to rectify faults one by one as follows: 1Remove the possibility of circuit error so that you can compare the recommended circuit of the corresponding type of microcontroller.2 Rule out the possibility of poor peripheral components; because peripheral components are nothing more than resistance and capacitance.3Rule out the possibility of using a crystal oscillator as a stop oscillator because you will not be experimenting with just one or two crystal oscillators.4Try changing the capacitor at both ends of the crystal; perhaps the crystal oscillator will begin to vibrate; please refer to the crystal oscillator capacitor size instructions.5In PC  B wiring, crystal oscillator circuit wiring should be as short as possible and as close to IC as possible, not between crystal oscillator feet. Ⅻ Summary of Chip OperationThe operation of the chip is mainly the operation of the registers in the chip. The registers in the chip have their unique address mapped on the memory, which is the operation of the corresponding address. To learn the chip, first look at the sequence diagram, then understand the corresponding registers, understand how to operate, define the required port (the program can recognize), write and read the operation program.Cross-sectional-views-of-chip-operationHow data is written to the chip, how it is read out, and through which port it is input or read.When connecting a chip through a bus, the first step is to understand the protocol of the bus. The chip connected to the I2c bus is controlled by the bus.1One 74HC595 lattice is used for column selection, and the other two are used for color selection. The lattice is equivalent to a set of diodes.The diode lights up only when one end is switched to a high level and the other to a low level. Just one end of the selection of different, bright different colors.Timer working mode selection: Set timer T1 in the high four digits and timer T0 in the low four digits. Then the last two characters of each mode set the working mode. When using interrupts, note that after entering the interrupt, the reset should be reset.2Serial port transceiver: Baud rate is generally set in mode 2 (automatic reloading initial value) because different devices have different data processing capabilities, the baud rate is set mainly to take care of low-speed devices and for communication between each other. The interrupt flag bit should be cleared by the software. When setting the serial port interrupt, either sending or receiving can enter the interrupt function, so pay attention to setting the interrupt function. (Self-sense generally sets a function, as the upper machine or lower machine).If you send interrupts, you have to figure out how to enter interrupts the first time, so you send them once and then you can enter interrupts. Only one byte can be sent at a time, and only after TI is set to one can the next byte be sent.3Pcf8591ad conversion, there are four channels of input, read PC  F8591, which channel, read is that channel input voltage, after the conversion of data stored in the chip, then read. Read to write the address of the chip, the son writes device address (0 x40 | channel number) and then reads the data.4Da conversion is to write the device address into the chip first, then write the sub-address (0x40) and then write the digital quantity to be converted. Device address chip information is introduced.5For the liquid crystal display, write data display, he will always display, do not continue to refresh, to change, only re-input.6For THE DS1302 clock chip, reading data is read out of the first data at the falling edge of the eighth clock when writing data, and then prepare for the next output. Pay attention to the writing of the program, but also pay attention to the position of the return value.7In Ds1302, the register is specified first, and then data is written to it. The registers on the chip data indicate the address. 8Initialization is best to write, in case you forget later. When reading or writing, the first operation is the lowest or highest bid, which can be judged according to the sequence diagram.9For the infrared transceiver, receiving, he is according to the length of time between the two falling edges to determine the high level or low level, write a program, first with the timer to determine the length of time, save, and then into binary (the program written to see more, very good).10Stepper motor: mainly used as switches, stepper motor torque decreases with the increase of speed. It is mainly used for automatic feeding of parts processing on machine tools. It can also be used in high-precision control places.Stepper motor is an open-loop control element stepper motor that converts electric pulse signal into angular displacement or linear displacement. In the case of the overload, motor speed, stop position depends only on the pulse signal frequency and pulse number, and are not affected by load change, when the stepper driver receives a pulse signal, it is driving a stepper motor according to set the direction of a fixed Angle, known as the "step Angle", its rotation is based on the Angle of the fixed step by step. The angular displacement can be controlled by controlling the number of pulses to achieve accurate positioning. At the same time, the speed and acceleration of the motor can be controlled by controlling the pulse frequency, achieving the purpose of speed regulation.11Servo motor : Servo motor refers to the engine that controls the operation of mechanical components in a servo system. It is an indirect transmission device for auxiliary motors. Servo motors can control speed, position accuracy is very accurate, voltage signal can be converted into torque and speed to drive the control object. Servo motor rotor speed is controlled by the input signal, and can respond quickly, in the automatic control system, used as an executive element, and has the characteristics of mechanical and electrical time constant is small, high linearity, starting voltage, etc., can receive the electrical signal into the motor shaft angular displacement or angular velocity output. It is divided into DC and AC servo motors. Its main characteristic is that when the signal voltage is zero, there is no rotation phenomenon, and the speed decreases uniformly with the increase of torque.12Chinese Characters overview: To output Chinese characters on display or printer, Chinese characters are designed into a dot matrix graph according to graphic symbols, and corresponding dot matrix codes (glyphs) are obtained.The unified encoding for the representation of Chinese characters in the computer is called the internal code (such as national code), and the internal code is unique (equivalent to the id number of the character). The encoding of Chinese characters formed to facilitate the input of Chinese characters is the input code, which belongs to the external code of Chinese characters. The input code varies with the encoding mode and is diverse. The Chinese character code formed for displaying and printing Chinese characters is the character code, and the computer finds the character code in the character library through the character code and realizes its conversion.Machine code: According to the GB code, each Chinese character has a certain binary code, but this code will conflict with THE ASCII code when handled internally by the computer. To solve this problem, the first byte of each GB code is incremented by 1. Because ASCII code only uses 7 bits, the "1" on the first digit can be used as a symbol to identify Chinese character codes. When the computer processes the code with the first digit of "1", it will be interpreted as the information of Chinese characters, and when it processes the code with the first digit of "0", it will be interpreted as the ASCII code. After such processing, the national code (internal code) is the machine's internal code.If put this "mouth" word graphic "." With "0" instead, you can very vividly get the "mouth" glyphs :0000H 0004H 3FFAH 2004H2004H 2004H2004H 2004H2004H 2004H2004H 2004H 3FFAH 2004H 0000H 0000H. Computer to output "mouth", find shows that character first address, according to the "mouth" machine code after calculation, to find a "mouth" glyph code, and then according to the glyph code (to) in binary character generator, in turn, scan control on the screen, which is where the "0" of the binary empty, is a place where "1" swept out of the window, Then you get the character graph of the mouth.Chinese characters are arranged according to the order of national standard codes and stored in the memory in the form of binary files, which constitute the Chinese character font library, also known as the Chinese character font library, called the Chinese character library1312864 liquid crystal: Each display point corresponds to a binary number, with 1 indicating on and 0 indicating off. The RAM that stores this lattice information is called the display data memory. To display a graph or Chinese character is to write the corresponding lattice information into the corresponding storage unit.When the horizontal address = 0FH, it will be reset to 00H, but it will not automatically add one to the vertical address. Therefore, when writing multiple data in a row, the program needs to determine whether the vertical address needs to be reset14GDRAM: Drawing display RAM provides 128×8 bytes of memory space. When changing the drawing RAM, the horizontal and vertical coordinate values are successively written, and then two bytes of data are written to the drawing RAM. The address counter (AC) will automatically increment the horizontal address (X address) and reset to 00H when the horizontal address is 0XFH. Vertical addresses will not be carried automatically plus 1. The drawing display must be turned off during writing to the drawing RAM,For C, a defined variable is automatically allocated space and its address is the name of the variable. Through this name, the data can be recruited in memory, and the new data can be obtained through an operation. In assembly, the programmer needs to define the storage space and send the data to the accumulator for operation, and the programmer needs to operate every step. In C, this is done by the compiler.FAQ1. What is the main function of microcontroller?Microcontroller is a compressed micro computer manufactured to control the functions of embedded systems in office machines, robots, home appliances, motor vehicles, and a number of other gadgets. A microcontroller is comprises components like - memory, peripherals and most importantly a processor.2. What is an example of a microcontroller?The examples of 8-bit microcontrollers are Intel 8031/8051, PIC1x, and Motorola MC68HC11 families. The 16-bit microcontroller performs greater precision and performance as compared to the 8-bit.3. What are the elements of a microcontroller?Therefore, the microcontroller must also satisfy the five basic elements of input, calculation, storage, output, and control. These are called five elements of microcontrollers.4. Which is best microprocessor or microcontroller?If you need access to large amounts of really fast memory then a microprocessor is likely your best option. A microcontroller is already embedded with memory so the memory choices are fewer than with a microprocessor. The maximum amount of FLASH memory available with most microcontrollers is usually around 2MB.5. What is difference between BIOS and CMOS?The BIOS is the program that starts a computer up, and the CMOS is where the BIOS stores the date, time, and system configuration details it needs to start the computer. ... CMOS is a type of memory technology, but most people use the term to refer to the chip that stores variable data for startup.6. Is CMOS a RAM or ROM?RAM and ROM are the products, but Complimentary Metal Oxide Semiconductor (CMOS) is the process they are built in. CMOS uses two different types of transistors to achieve a lower overall power consumption.7. Whats an RTC battery?The Real Time Clock (RTC) battery provides power for the internal clock/calendar and for maintaining system configuration settings. This error can occur when a machine has been left turned-off for an extended period of time (approximately one to four months), and it is the result of a depleted RTC battery.            

IntroductionⅠ What is a Wireless Transmitter?Ⅱ How to Make a Transmitter and Receiver Ⅲ Wireless Transmitter vs Wireless Receiver    3.1 Wireless Transmitter    3.2 Wireless Receiver    3.3 What are Optical Transmitters and Receivers?    3.4 How do You Use a Wireless Transmitter? Ⅳ Transmitter Specifications Ⅴ The Types of Transmitter Based on Modulation Scheme and Conversion Technique Employed    5.1 AM Transmitter    5.2 FM Transmitter    5.3 SSB Transmitter    5.4 Direct Conversion Transmitter    5.5 Super Heterodyne TransmitterⅥ Smart Wireless Transmitters    6.1 What are Smart Transmitters?    6.2 What are the Main Features of Smart Transmitters?Ⅶ 5 Tips to Optimize Your Sennheiser Wireless System    7.1 Don’t Cover the Antenna    7.2 Fresh Batteries are Essential    7.3 Frequency Selection is Important When Using Multiple Systems    7.4 Maintain Line of Sight between Components    7.5 Keep Transmitters and Receivers as Close as PossibleⅧ Answers to 6 Questions about the Wireless TransmitterIntroduction A wireless transmitter is a telecommunications device that generates radio waves in order to broadcast or transfer data via an antenna.This article on the transmitter specs, usage, and other parts of a full introduction will allow you to have a more detailed grasp of the wireless transmitter.Ⅰ What is a Wireless Transmitter?A wireless transmitter and associated receiver are required for devices that communicate data without the use of cables. The transmitter converts the audio signal to a radio signal and broadcasts it via an antenna as a radio wave. The antenna may protrude from the transmitter's bottom or be hidden within the transmitter. Government rules regulate the strength of radio transmission. Depending on the conditions and signal quality, the signal can successfully go up to 1,000 feet. There are two types of transmitters available. A "body-pack" or "belt-pack" transmitter, for example, is a compact box the size of a deck of cards (or smaller in some cases). The transmitter is worn on the body or clipped to the user's belt. A body-pack transmitter is commonly hooked to a guitar strap or attached directly to an instrument such as a trumpet or saxophone for instrument applications. The transmitter is incorporated into the handle of a portable wireless microphone, resulting in a wireless microphone that is just slightly larger than a normal wired microphone. For handheld wireless microphones, a range of microphone elements or "heads" are usually offered. A battery (typically a 9-volt alkaline type) is required to run all wireless transmitters.Figure-1 A wireless routerA router with an integrated wireless transmitter and receiver is included in the home or office wireless local area network (WLAN). Most routers also include a modem, allowing a single, high-speed Internet account to be shared by all connected computers. Instead of using Ethernet cables to connect the computers, each has a wireless network card (or wireless adapter) that has its own transmitter and receiver on board. Now, for instance, an individual computer can send a data request to the router, and the router can receive the request, forward it to the appropriate party, and then send the return response.Ⅱ How to Make a Transmitter and ReceiverThe Video Shows: How to make a transmitter and receiveMake your very own transmitter and receiver! Ⅲ Wireless Transmitter vs Wireless Receiver3.1 Wireless TransmitterThe radio's transmitter is powered by an alternating current flowing through a conductor (in this case an antenna). The alternating current changes direction very quickly, frequently millions or billions of times per second. The energy contained in such a fastly alternating current can be converted into Electromagnetic (EM) radiation. Electrons flowing as current produce electromagnetic radiation in the form of photons (energy packets).The resulting waves are sinusoidal, but their amplitude and frequency can be altered through modulation.3.2 Wireless ReceiverReceivers operate in the inverse of how transmitters do.The incident radio waves generate a tiny alternating current in the receiver's antenna (the photons impart their energy onto the electrons in the wire, resulting in the current). An alternating current is generated because EM waves oscillate). This alternating current signal is routed to the receiver's input.It's vital to recognize that when you tune a radio, you're selecting a frequency to listen to. To get the clearest signal, set your radio to the circuit's resonant frequency.' This is determined by the components used.3.3 What are Optical Transmitters and Receivers?The optical fiber communication system consists primarily of a transmitter and receiver, with the transmitter located on one end of a fiber cable and the receiver located on the other end of the cable. The majority of systems make use of a transceiver, which is a module that includes both a transmitter and a receiver. The transmitter receives an electrical signal and converts it to an optical signal using an LED or laser diode.Figure-2 Fiber-optic-data-linkA connector connects the light signal from the transmitter end to the fiber cable, which is then broadcasted through the cable. The light signal from the fiber end can be connected to a receiver, and wherever a detector converts the light signal to an electrical signal, it is conditioned appropriately for use by the receiving equipment.3.4 How do You Use a Wireless Transmitter?An electromagnetic disturbance is a radio wave. It spreads out in the same way that ripples in water do.First, the current flows through a wire. The wire is then surrounded by an electromagnetic field.This can be used by transmitters. They can send a pulse of electricity through a copper antenna.Furthermore, one end of the antenna will be grounded. This will restrict the signal to a single pulse.Metal effectively traps any radio waves that come into contact with it because it is a conductor of both electricity and magnetism. As a result, large metal objects in the home, such as a refrigerator, will interfere with the Wi-Fi signal. The radio waves will then emit in a regular pattern, much like ripples. The frequency of the emission will be measured in hertz (Hz).Transmitters create a carrier frequency, which is then mixed with the data signal and broadcast. This signal will be received by the receiver, which will then divide the two frequencies into their individual portions.Ⅳ Transmitter Specifications1DC coupled LEDs are used.2A serial port is Max232 IC Driver. 3The wavelength of the source is 660nm. 4The data rate is 1 Mbps.5The highest input voltage is +5V.6The maximum supply current is 100 mA. 7The maximum input voltage is +5V.8The supply voltage is +15V DC.9The LED driver is on board IC Driver.10The interface connectors are 2mm sockets. 11The type of input signal is digital data.  Ⅴ The Types of Transmitter Based on Modulation Scheme and Conversion Technique Employed The following are the different types of transmitters based on the modulation scheme and conversion technique used.5.1 AM TransmitterFigure-3 Typical block diagram of AM transmitter systemThe frequency range of an AM radio system is 540 to 1700kHz, with an IF of around 455 kHz. The frequencies are separated by 10 kHz.To convert audio information into an AM modulated signal, an AM transmitter employs amplitude modulation. AM modulation employs audio as the modulating signal and a high-frequency signal as the carrier. To achieve AM modulated output, the amplitude of the carrier signal is varied by the amplitude of the modulating audio signal.5.2 FM Transmitter          Figure-4    FM transmitter system block diagramFM radio systems operate in the frequency range of 88 to 108 MHz, with an IF of approximately 10.7 MHz. To convert audio information into an FM modulated signal, an FM transmitter employs frequency modulation. FM modulation makes use of audio as the modulating signal (Fm) and a high-frequency signal as the carrier. To achieve FM modulated output, the frequency of the carrier signal (Fc) is varied in accordance with the amplitude of the modulating audio signal.5.3 SSB Transmitter Figure-5 SSB transmitter block diagramThe upper and lower sidebands are transmitted by the AM transmitter. The upper band represents the sum of Fc and Fm, while the lower band represents the difference between Fc and Fm. A single-sideband (either upper or lower) is transmitted by an SSB transmitter, not both. In comparison to an AM transmitter, an SSB transmitter saves bandwidth and power.5.4 Direct Conversion TransmitterLet's take a look at how a direct conversion transmitter works. The signal constellation produced by this transmitter type is known as QPSK, which stands for Quadrature Phase Shift Keying.The first bit of digital data to be transmitted is divided into I and Q signals.The I and Q signals are processed by DACs.Low pass filtering is used to feed the output of DACs to mixers.The architecture employs LO (local oscillator). Before the mixing process, the LO signal is phase-shifted by 90 degrees to one of the mixers.The mixed I and Q components are added together to produce a QPSK modulated signal.Before transmission into the air, the QPSK modulated signal is amplified using a PA (Power Amplifier).Figure-6 Direct conversion transmitter5.5 Super Heterodyne TransmitterFigure-7 Superheterodyne-transmitterAfter obtaining a modulated signal via direct conversion transmitter, this architecture employs one more mixing component. The signal is bandpass filtered both before and after mixing. This necessitates the inclusion of one more LO (Local Oscillator) in the design. This type, like other transmitter systems, employs PA (Power Amplification) prior to transmission. With the help of gain control, AGC is used to vary the amplitude of the output signal. AGC stands for Automatic Gain Control.Ⅵ Smart Wireless Transmitters6.1 What are Smart Transmitters?Smart transmitters are controlled by a microprocessor. They also include an in-built sensor. The sensor enables a transmitter to filter the surrounding atmosphere. Furthermore, the transmitters can store data in memory. You can program transmitters to retain a default setting using memory storage.6.2 What are the Main Features of Smart Wireless Transmitters?The following are the key features of OMNI's smart wireless transmitters:Multiple sensors can be added for varying measurement changes.The transmitter is then adjusted to produce linear results.The transmitters are self-calibration capable.The transmitters can self-diagnose. They are capable of detecting faults and maintenance alerts.Ⅶ 5 Tips to Optimize Your Sennheiser Wireless SystemFor years, Sweetwater has configured and used large-scale Sennheiser wireless microphone systems. There are some simple steps you can take to get the most out of your Sennheiser wireless system in terms of channel count, range, and sound quality.7.1 Don’t Cover the AntennaThe antenna on a transmitter should never be covered for optimal performance. When using a handheld microphone, take care not to cover the antenna with your hand. If you don't see an antenna on your microphone, it's most likely hidden inside the last few inches of its body. Hold the microphone closer to its head/capsule to avoid covering it with your hand as you pick it up.Figure-8 Don't cover the antennaWhen wearing a belt pack with an external antenna, make sure the antenna isn't wadded up or bent. This is not only bad for the antenna (bending a wire enough times will cause it to break), but it also severely reduces its transmission. With a wadded-up antenna, you'll get limited range and more dropouts.7.2 Fresh Batteries are EssentialFigure-9 BatterySignal strength and operational range decrease when the transmitter's battery expires, so even if the battery isn't fully dead, it's better to change it at the start of every performance, event, or service.7.3 Frequency Selection is Important When Using Multiple SystemsFigure-10 Frequency SelectionTo avoid interfering with each other, the frequencies of numerous wireless systems must be properly synchronized. It's not always enough to have distinct frequencies. Using wireless systems from the same manufacturer and series is usually the best way to do this — Sennheiser's wireless systems automatically use frequencies that are already pre-coordinated to avoid interference. Consult an expert if you're integrating systems from various manufacturers or series.7.4 Maintain Line of Sight between ComponentsImproper antenna installation is the most prevalent cause of signal losses. Between the antennas and the transmitters, there should always be a clear line of sight. If this isn't possible in your rack, the antennas should be put distant from the receivers, perhaps on a wall, on a balcony rail, from the ceiling, or somewhere else where line-of-sight placement is possible.Figure-11 Maintain line of sight between componentsKeep in mind that the human body is a great RF energy absorber. Your wireless transmitter is unlikely to have enough "oomph" to carry an entire audience of people on their feet. If your antennae are in the rear of the room, the pastor's back, which requires the signal to pass through his body on its way to the receiver, may not be the best place for the belt pack transmitter.7.5 Keep Transmitters and Receivers as Close as PossibleIf you're having trouble getting clear reception, consider placing the receivers closer to the stage to shorten the distance between the transmitters and receivers. If that isn't possible, consider moving the antennae closer together by mounting them remotely. If you need to run long antenna cables, don't skimp on quality to save money — obtain the lowest-loss cable you can find. It is suggested that you use RG-8. If the cable line is longer than 25 feet, an antenna booster may be required, and it's time to contact a professional.Ⅷ Answers to 6 Questions about the Wireless Transmitter1. What is a transmitter in a wireless system?A wireless system consists of two main components: a transmitter, and a receiver. The transmitter handles the conversion of the audio signal into a radio signal and broadcasts it as a radio wave via an antenna. The antenna may stick out from the bottom of the transmitter or it may be concealed inside.2. How do I connect Bluetooth kit to FM transmitter?Simply turn on the Bluetooth on your cellphone. Or whichever device you plan on using. And search for the t-ten. And just connect the t10 and and just like that is paired.3. Can any transmitter work with any receiver?You can use a transmitter with any receiver. BUT you have to have a way of changing the antenna when you transmit. There are antenna relays for this purpose that will automatically make the change for you. The power of the transmitter would quickly destroy your receiver.4. What are the main features of transmitter?What are the main features of a transmitter? Explanation: Some of the main features which make the transmitter complex are higher clock speed, higher transmit power, directional antennas and need for a linear amplifier.5. Is transmitter is same as sender?What's the difference between sender and transmitter here. Many times both terms are used for the same thing. Could it be here "Sender und Sendegeraet"? The HFN values in the sender and the transmitter are different,i.e. the HFN synchronization between the sender and receiver is lost.6. What is perfect transmitter?The important feature of the transmitter is extremely fast current, turn-off time, less than 1 μs for the shallowest depth, while the current after the ramp time is practically absent. douwdek0 and 6 more users found this answer helpful. 

Ⅰ IntroductionWhen connected to a voltage source, capacitors are basic passive devices that can store an electrical charge on their plates. The capacitor, like a miniature rechargeable battery, has the ability or "capacity" to store energy in the form of an electrical charge, producing a potential difference (Static Voltage) across its plates. Capacitors come in a variety of sizes and shapes, ranging from tiny capacitor beads used in resonance circuits to enormous power factor correction capacitors, but they always store charge. this video shows how capacitors work CatalogⅠ IntroductionⅡ Types of Capacitor2.1 Dielectric Capacitor2.2 Variable Capacitor Symbol2.3 Film Capacitor Type2.4 Axial Lead Type2.5 Ceramic Capacitors2.6 Electrolytic Capacitors2.7 Aluminium Electrolytic Capacitors2.8 Tantalum Electrolytic Capacitors2.9 Frequently Asked Questions About Different Types Of CapacitorⅢ The Capacitance of a Capacitor3.1 SI Unit of Capacitance3.2 μF vs. nF vs. pF3.3 Frequently Asked Questions about the Capacitance of a CapacitorⅣ Capacitor Conversion: µF-nF-pF 4.1 Capacitor Conversion Chart4.2 Popular Capacitor Conversions4.3 Frequently Asked Questions about Capacitor ConversionⅤ Capacitor Color Code5.1 Capacitor Colour Code Tables5.2 Color Codes of Different Capacitors5.3 Frequently Asked Questions about Capacitor Color CodeⅥ Capacitor Code6.1 Types of Capacitor Code6.2 Frequently Asked Questions about Capacitor CodeⅦ Capacitor Code Calculator7.1 Capacitor Safety Discharge Calculator Tool7.2 Series and Parallel Capacitance Calculator Ⅱ Types of CapacitorFrom very small delicate trimming capacitors used in oscillator or radio circuits to enormous power metal-can type capacitors used in high voltage power correction and smoothing circuits, capacitors are available. The dielectric used between the plates is commonly used to make comparisons between different types of capacitors. There are variable varieties of capacitors, just like resistors, that allow us to adjust their capacitance value for use in radio or "frequency tuning" circuits. Metallic foil is interwoven with thin sheets of either paraffin-impregnated paper or Mylar as the dielectric material in commercial capacitors. Because the metal foil plates are rolled up into a cylinder to produce a compact box with the insulating dielectric material sandwiched in between, some capacitors resemble tubes. Ceramic materials are frequently used to make small capacitors, which are subsequently sealed with epoxy resin. Capacitors play a crucial role in electronic circuits in any case, therefore here are a few of the most "common" capacitor types available. 2.1 Dielectric CapacitorWhen a constant variation in capacitance is necessary for tuning transmitters, receivers, and transistor radios, dielectric capacitors are normally of the variable variety. Multi-plate air-spaced variable dielectric capacitors have a set of fixed plates (the stator vanes) and a set of movable plates (the rotor vanes) that move in between the fixed plates. The overall capacitance value is determined by the position of the moving plates concerning the fixed plates. When the two sets of plates have entirely meshed together, the capacitance is usually at its highest. With breakdown voltages in the thousands of volts, high voltage tuning capacitors have relatively large spacings or air gaps between the plates. 2.2 Variable Capacitor SymbolTrimmers are pre-set type variable capacitors that are available in addition to continuously variable varieties. These are typically small devices that may be modified or "pre-set" to a specific capacitance value with a small screwdriver, and are available in very low capacitances of 500pF or less, and are non-polarized. variable capacitor symbol 2.4 Axial Lead TypeLong thin strips of thin metal foil with the dielectric material sandwiched between them are twisted into a tight roll and then sealed in paper or metal tubes for film and foil capacitors. To lessen the possibility of tears or punctures in the film, these film types require a significantly thicker dielectric film and are thus better suited to lower capacitance values and bigger case sizes. axial-lead-type Metalized foil capacitors have the conductive film metalized sprayed directly onto each side of the dielectric, giving the capacitor self-healing capabilities and allowing thinner dielectric films to be used. For a given capacitance, this enables for larger capacitance values and smaller case sizes. Film and foil capacitors are typically employed in situations that require more power and precision. 2.5 Ceramic CapacitorsCeramic capacitors, also known as Disc capacitors, are created by coating two sides of tiny porcelain or ceramic disc with silver and stacking them together to form a capacitor. A single ceramic disc of roughly 3-6mm is utilized for very low capacitance values. Ceramic capacitors have a high dielectric constant (High-K) and are available in tiny physical sizes, allowing for relatively high capacitances. ceramic capacitor Because they are non-polarized and exhibit huge non-linear changes in capacitance with temperature, they are employed as de-coupling or by-pass capacitors. Ceramic capacitors range in size from a few picofarads to one or two microfarads, but their voltage ratings are often modest. A three-digit code is usually inscribed on the body of ceramic capacitors to identify their capacitance value in pico-farads. The first two digits usually represent the capacitor's value, while the third digit represents the number of zeros to be added. A ceramic disc capacitor marked 103, for example, would indicate 10 and 3 zeros in pico-farads, which is equal to 10,000 pF or 10nF. The numerals 104, for example, represent 10 and 4 zeros in pico-farads, which is comparable to 100,000 pF or 100nF, and so on. The digits 154 on the ceramic capacitor image above represent 15 and 4 zeros in pico-farads, which is comparable to 150,000 pF, 150nF, or 0.15F. To signify their tolerance value, letter codes are occasionally employed, such as J = 5%, K = 10%, M = 20%, and so on. 2.6 Electrolytic CapacitorsWhen very large capacitance values are required, electrolytic capacitors are typically utilized. Instead of employing a very thin metallic film layer for one of the electrodes, a semi-liquid electrolyte solution in the form of jelly or paste is employed (usually the cathode). The dielectric is a very thin layer of oxide that is produced electrochemically in the manufacturing process and has a thickness of fewer than ten microns. Because the insulating layer is so thin, capacitors with a big capacitance value can be made in a small physical size because the distance between the plates, d, is so short. electrolytic capacitor The majority of electrolytic capacitors are polarized, which means that the DC voltage applied to the capacitor terminals must be of the correct polarity, i.e. positive to the positive terminal and negative to the negative terminal, or the insulating oxide layer will be broken down and permanent damage may result. The polarity of all polarized electrolytic capacitors is indicated with a negative sign to signify the negative terminal, which must be followed. Due to their huge capacitance and small size, electrolytic capacitors are commonly employed in DC power supply circuits to help reduce ripple voltage or for coupling and decoupling applications. Electrolytic capacitors have a low voltage rating, which means that they can't be utilized on AC supply because of their polarization. Aluminium Electrolytic Capacitors and Tantalum Electrolytic Capacitors are the two most common types of electrolytes. 2.7 Aluminium Electrolytic CapacitorsThe plain foil type and the etched foil type are the two varieties of Aluminum Electrolytic capacitors. These capacitors have extremely high capacitance values for their size due to the thickness of the aluminum oxide coating and the high breakdown voltage.aluminium electrolytic capacitor A DC current is used to anodize the capacitor's foil plates. The polarity of the plate material is established during the anodizing process, which defines which side of the plate is positive and which side is negative. The aluminum oxide on the anode and cathode foils has been chemically etched to increase surface area and permittivity, which makes the etched foil type different from the plain foil type. This results in a smaller capacitor than a normal foil type of comparable value, but it has the disadvantage of not being able to handle strong DC currents. Their tolerance range is also fairly high, reaching up to 20%. Capacitance values for aluminum electrolytic capacitors typically range from 1uF to 47,000uF. Plain foil electrolytes are better suited as smoothing capacitors in power supply, while etched foil electrolytes are best employed in the coupling, DC blocking, and by-pass circuits. However, because aluminum electrolytes are “polarized” devices, inverting the applied voltage on the leads will damage the insulating layer within the capacitor, as well as the capacitor itself. The capacitor's electrolyte, on the other hand, aids in the healing of a damaged plate if the damage is minor. The electrolyte has the power to re-anodize the foil plate since it can self-heal a damaged plate. The electrolyte can remove the oxide layer from the foil if the anodizing process is reversed, as it would if the capacitor was connected with reverse polarity. Because the electrolyte can conduct electricity, if the aluminum oxide layer is removed or destroyed, current can flow from one plate to the other, causing the capacitor to fail, "so be alert." 2.8 Tantalum Electrolytic CapacitorsTantalum Electrolytic Capacitors and Tantalum Beads come in both wet (foil) and dry (solid) electrolytic varieties, with dry tantalum being the most prevalent. Solid tantalum capacitors have a second terminal of manganese dioxide and are physically smaller than analogous aluminum capacitors. Tantalum oxide's dielectric characteristics are superior to those of aluminum oxide, resulting in reduced leakage currents and greater capacitance stability, making it ideal for blocking, by-passing, decoupling, filtering, and timing applications. Tantalum capacitors, although being polarized, can withstand being linked to a reverse voltage considerably better than aluminum capacitors, but they are rated at much lower operating voltages. Solid tantalum capacitors are commonly employed in circuits with low AC voltages compared to DC voltages. Some tantalum capacitors, on the other hand, comprise two capacitors in one, connected negative-to-negative to make a “non-polarized” capacitor for use in low voltage AC circuits. The positive lead of a tantalum bead capacitor is usually identifiable by a polarity mark on the capacitor body, which has an oval geometrical shape. Capacitance values typically vary from 47nF to 470F. 2.9 Frequently Asked Questions About Different Types Of Capacitor1. Which type of capacitor is best?Class 1 ceramic capacitors offer the highest stability and lowest losses. They have high tolerance and accuracy and are more stable with changes in voltage and temperature. Class 1 capacitors are suitable for use as oscillators, filters, and demanding audio applications. 2. Does the type of capacitor matter?Yes, the type of capacitor can matter. Different types of capacitor have different properties. Some of the properties that vary between capacitor types: polarized vs unpolarized. 3. Are all capacitors the same?Not all capacitors are created equal. Each capacitor is built to have a specific amount of capacitance. The capacitance of a capacitor tells you how much charge it can store, more capacitance means more capacity to store charge. 4. Which type of capacitor is known as Polarised capacitor?Electrolytic Capacitors. The Electrolytic Capacitors are the capacitors which indicate by the name that some electrolyte is used in it. They are polarized capacitors which have anode + and cathode − with particular polarities. A metal on which insulating oxide layer forms by anodizing is called as an Anode. 5.Which capacitors are not polarized?Ceramic, mica and some electrolytic capacitors are non-polarized. You'll also sometimes hear people call them "bipolar" capacitors. A polarized ("polar") capacitor is a type of capacitor that have implicit polarity -- it can only be connected one way in a circuit. Ⅲ The Capacitance of a CapacitorThe Farad (abbreviated to F) is the unit of capacitance and is named after the British physicist Michael Faraday. Capacitance is the electrical property of a capacitor and is the measure of a capacitor's ability to store an electrical charge onto its two plates. When a charge of One Coulomb is stored on the plates by a voltage of One volt, a capacitor has a capacitance of One Farad. It's worth noting that capacitance, or C, is always positive and has no negative units. However, because the Farad is a relatively big unit of measurement on its own, sub-multiples such as micro-farads, nano-farads, and pico-farads are commonly used. 3.1 SI Unit of CapacitanceCapacitors are a common type of electrical component, and their values are usually stated in microfarads, F (or uF if a micro character is not available), nanofarads, nF, or picofarads, pF. Microfarad (μF)  1μF = 1/1,000,000 = 0.000001 = 10-6 FNanofarad (nF)  1nF = 1/1,000,000,000 = 0.000000001 = 10-9 FPicofarad (pF) 1pF=1/1,000,000,000,000 = 0.000000000001 = 10-12 F 3.2 μF vs. nF vs. pFAlthough most current circuits and component descriptions use the nomenclature F, nF, and pF to specify capacitor values, older circuit designs, circuit descriptions, and even the components themselves may employ a variety of non-standard acronyms that aren't always evident. The following are the main changes for the various capacitance sub-multiples: Micro-Farad, µF: Larger value capacitors, such as electrolytic capacitors, tantalum capacitors, and even some paper capacitors measured in micro-Farads, may have been labeled with uF, mfd, MFD, MF, or UF. All of these terms refer to the value in µF. Electrolytic and tantalum capacitors are commonly connected with this nomenclature. Nano-Farad, nF: Because nF or nano-Farads nomenclature was not frequently used prior to terminology standardization, this submultiple lacked a variety of abbreviations. The term nanofarad has gained in popularity in recent years, while it is still not widely used in some countries, with values given in huge numbers of picofarads, such as 1000pF for 1 nF, or fractions of a microfarad, such as 0.001 µF for a nanofarad. Ceramic capacitors, metalized film capacitors, including surface mount multilayer ceramic capacitors, and even some modern silver mica capacitors all use this terminology. Pico-Farad, pF: The value in picoFarads, pF, was again indicated using a variety of acronyms.  MicroromicroFarads, mmfd, MMFD, uff, µµFwere among the terms used. All of these numbers are in pF. Picofarad capacitor values are commonly employed in radio frequency, RF circuits, and equipment. As a result, this nomenclature is most commonly associated with ceramic capacitors, however, it is also applied to silver mica capacitors and some film capacitors. The conversion of values from one submultiple to the next has been aided by the standardization of terminology. It has resulted in a significant reduction in the potential for misunderstanding. Converting from µF to nF and pF is simpler. This is important when a capacitor value is listed in one way on a circuit diagram and another way on a list of electronic components distributors. Because different electrical component manufacturers label components differently, the capacitance conversion table is highly useful. For example, some manufacturers label their equivalent capacitors as a fraction of a microfarad, while others label them as a fraction of a nanofarad, and so on. Electrical component wholesalers and retailers will prefer to adopt the manufacturer's nomenclature. Similarly, circuit diagrams may use different symbols to represent components to maintain commonality, etc. As a result, being able to convert between picofarads, nanofarads, and microfarads, as well as vice versa, is beneficial. When the bill of materials or parts list for the circuit has values expressed in microfarads, µF, and picofarads, pF, this can aid identify components labeled in nanofarad values. It is generally useful to be able to utilize a capacitance conversion calculator like the one above, but it is also important to be familiar with the conversions and popular equivalents, such as 1000pF = nanofarad and 100nF = 0.1µF. These conversions become second nature while working with electrical components and designing electronic circuits, but the capacitance conversion tables and calculators can still be quite useful. Capacitors, as well as other electronic components like inductors, benefit from these conversions. 3.3 Frequently Asked Questions about the Capacitance of a Capacitor1. What is capacitance in simple terms?Capacitance is the ability of a system of electrical conductors and insulators to store electric charge when a potential difference exists between the conductors. Capacitance is expressed as a ratio of the electrical charge stored to the voltage across the conductors. 2.What is C in capacitance?The capacitance C is the ratio of the amount of charge q on either conductor to the potential difference V between the conductors, or simply C = q/V. 3.What is difference between capacitor and capacitance?Capacitance is nothing but the ability of a capacitor to store the energy in form of electric charge. In other words, the capacitance is the storing ability of a capacitor. It is measured in farads. 4.What is the formula of capacitor?The governing equation for capacitor design is: C = εA/d, In this equation, C is capacitance; ε is permittivity, a term for how well dielectric material stores an electric field; A is the parallel plate area; and d is the distance between the two conductive plates. 5.What four factors affect capacitance?The capacitance of a capacitor is affected by the area of the plates, the distance between the plates, and the ability of the dielectric to support electrostatic forces. Ⅳ Capacitor Conversion: µF-nF-pF  The use of the nanofarad (nF) is less common in some fields, with values stated in fractions of a µF and huge multiples of picofarads (pF). When components marked in nanofarad are available, it may be necessary to convert to nanofards, nF in these circumstances. When a circuit diagram or electronic components list mentions the value in picofarads, for example, and listings for an electronic component distributor or electronic components store state it in another way, it can be confusing. Capacitor values can be in the 109 range or even higher, thanks to the introduction of supercapacitors. The common prefixes pico (10-12), nano (10-9), and micro (10-6) are often used to avoid misunderstanding with high numbers of zeros connected to the values of different capacitors. When converting between them, a capacitor conversion chart or capacitor conversion table for the various capacitor values can be useful. Another requirement for capacitance conversion is that the actual capacitance value is reported in picofarads in some capacitor marking systems, therefore the value must be converted to the more common nanofarads or microfarads. 4.1 Capacitor Conversion ChartMicrofarads ( µF)Nanofarads(nF)Picofarads(pF)0.0000010.00110.000010.01100.00010.11000.001110000.0110100000.11001000001100010000001010000100000001001000001000000004.2 Popular Capacitor ConversionsCapacitor values can be written in a few different ways. A ceramic capacitor, for example, is frequently assigned a value of 100nF. It is often interesting to realize that this is 0.1µF when utilized in circuits with electrolytic capacitors. These handy conversions can aid in the design, construction, and maintenance of circuits. When building circuits or employing capacitors in any fashion, keeping these capacitor conversions in mind when values migrate from picofarads to nanofarads and then nanofarads to microfarads is typically beneficial. A more comprehensive table of conversion factors to convert between the different values, nF to pF, µF to nF etc is given below.Table of Conversion Factors to Convert between µF,nF and pF convertmultiply by:pF     to     nF1 x 10-3pF     to     µF1 x 10-6nF     to     pF1 x 103nF     to     µF1 x 10-3µF     to     pF1 x 106µF     to     nF1 x 103 4.3 Frequently Asked Questions about Capacitor Conversion1. Can I replace a capacitor with a higher uF?An electric motor start capacitors can be replaced with a micro-farad or UF equal to or up to 20% higher UF than the original capacitor serving the motor. 2.What happens if I use a higher uF capacitor?The higher the number of micro-farads, the more energy the capacitor can hold. In theory, if a device has a high uF, it will last longer in a power outage.3.What happens if you use the wrong size capacitor?If the wrong run capacitor is installed, the motor will not have an even magnetic field. This will cause the rotor to hesitate at those spots that are uneven. This hesitation will cause the motor to become noisy, increase energy consumption, cause performance to drop, and cause the motor to overheat. 4.Can I replace a capacitor with a lower capacitance?Yes, it's possible given the necessary skills and tools. Yes, it's safe. The only rating that matters for safety is the rated voltage: if you put a higher voltage than the maximum you might see your cap explode. 5.Can I use a run capacitor in place of a start capacitor?The capacitance and voltage ratings would have to match the original start capacitor specification. A start capacitor can never be used as a run capacitor, because it cannot not handle current continuously. Ⅴ Capacitor Color Code5.1 Capacitor Colour Code TablesWhen the capacitance value is a decimal value, problems with the marking of the "Decimal Point" arise since it is easily overlooked, leading to a misunderstanding of the real capacitance value. Instead of the decimal point, letters like p (pico) or n (nano) are used to indicate the position and weight of the number. A capacitor might be labeled as n47 = 0.47nF, 4n7 = 4.7nF, or 47n = 47nF, for example. Also, capacitors are occasionally labeled with the capital letter K to indicate a value of one thousand pico-Farads, thus a capacitor marked 100K would be 100 x 1000pF or 100nF. An International color-coding scheme was devised many years ago as a simple manner of identifying capacitor values and tolerances to reduce the confusion regarding letters, numbers, and decimal points. The Capacitor Colour Code system, which consists of colored bands (in spectral order) and whose meanings are given below, is a system that consists of colored bands (in spectral order). Band ColourDigit ADigit BMultiplier DTolerance (T) > 10pfTolerance (T) < 10pfTemperature Coefficient (TC)Black00x1± 20%± 2.0pF Brown11x10± 1%± 0.1pF-33×10-6Red22x100± 2%± 0.25pF-75×10-6Orange33x1,000± 3% -150×10-6Yellow44x10,000± 4% -220×10-6Green55x100,000± 5%± 0.5pF-330×10-6Blue66x1,000,000  -470×10-6Violet77   -750×10-6Grey88x0.01+80%,-20%  White99x0.1± 10%± 1.0pF Gold  x0.1± 5%  Silver  x0.01± 10%  Capacitor Colour Code Table Band ColourVoltage Rating (V) Type JType KType LType MType NBlack4100 1010Brown62001001.6 Red10300250435Orange15400 40 Yellow205004006.36Green25600 1615Blue35700630 20Violet50800   Grey 900 2525White31000 2.53Gold 2000   Silver     Capacitor Voltage Colour Code Table Capacitor Voltage ReferenceType J–  Dipped Tantalum Capacitors.Type K–  Mica Capacitors.Type L–  Polyester/Polystyrene Capacitors.Type M–  Electrolytic 4 Band Capacitors.Type N–  Electrolytic 3 Band Capacitors. 5.2 Color Codes of Different Capacitors 1.Metalised Polyester Capacitor  2. Disc & Ceramic Capacitor  For many years, unpolarized polyester and mica molded capacitors were coded using the Capacitor Colour Code system. Although this color coding method is no longer in use, many “old” capacitors can still be found. Small capacitors, such as film or disk kinds, now comply with the BS1852 Standard and its new replacement, BS EN 60062, which replaces the colors with a letter or number coding system. 5.3 Frequently Asked Questions about Capacitor Color Code1. What do capacitor colors mean?All the color bands painted on the capacitors body are used to indicate the capacitance value and capacitance tolerance. The color codes used to represent the capacitance values and capacitance tolerance is similar to that used to represent resistance values and resistance tolerance. 2.How do you read a capacitor code?If you have a capacitor that has nothing other than a three-digit number printed on it, the third digit represents the number of zeros to add to the end of the first two digits. The resulting number is the capacitance in pF. For example, 101 represents 100 pF: the digits 10 followed by one additional zero. 3.Which type of capacitor is available in color code?A color code was used on polyester capacitors for many years. It is now obsolete, but of course there are many still around. The colors should be read like the resistor code, the top three color bands giving the value in pF. Ignore the 4th band (tolerance) and 5th band (voltage rating). 4.Are capacitors color coded?The capacitors use a capacitor color code similar to the resistors color code (3, 4 or 5 bands). The first two colors indicate significant digits of the value of the capacity (in pF), the next colour is the corresponding power of 10, the other two colors are optional and indicate tolerance and maximum voltage. Ⅵ Capacitor Code6.1 Types of Capacitor CodeFor example, a capacitor labeled 474J should be read as 47 times the value listed in Table 1 corresponding to the third number, in this case, 10000: 47 * 10000 = 470000 pF = 470 nF = 0.47µF, with the J indicating a 5% tolerance. If a temperature coefficient is present, the second letter will be it. You'll rapidly learn to tell whether a capacitor's value is expressed in pF, nF, or µF based on its size and kind. The capacitance of a capacitor designated 2A474J is encoded as mentioned above; the two initial signs are the voltage rating, which can be decoded from table 2 below. According to the EIA standard, 2A is a 100V DC rating. Some capacitors are only marked 0.1 or 0.01, mostly in these cases the values are given in µF. Some small capacitance capacitors contain an R between the numbers, such as 3R9, which indicates that the value is less than 10pF and has nothing to do with resistance. 3R9 has a 3.9pF value. Table 1 – Capacitor codes with letters and tolerances3rd numberMultiply withLetterTolerance01D0.5pF110F1%2100G2%31,000H3%410,000J5%5100,000K10%61,000,000M20%7Not usedM20%80.01P+100%/-0%90.1Z+80%/-20% Table 2A – Electronic Industries Alliance (EIA) – DC voltage code table0E = 2.5 VDC2A = 100 VDC3A = 1 kVDC0G = 4.0 VDC2Q = 110 VDC3L = 1.2 kVDC0L = 5.5 VDC2B = 125 VDC3B = 1.25 kVDC0J = 6.3 VDC2C = 160 VDC3N = 1.5 kVDC1A = 10 VDC2Z = 180 VDC3C = 1.6 kVDC1C = 16 VDC2D = 200 VDC3D = 2 kVDC1D = 20 VDC2P = 220 VDC3E = 2.5 kVDC1E = 25 VDC2E = 250 VDC3F = 3 kVDC1V = 35 VDC2F = 315 VDC3G = 4 kVDC1G = 40 VDC2V = 350 VDC3H = 5 kVDC1H = 50 VDC2G = 400 VDC3I = 6 kVDC1J = 63 VDC2W = 450 VDC3J = 6.3 kVDC1M = 70 VDC2J = 630 VDC3U = 7.5 kVDC1U = 75 VDC2I = 650 VDC3K = 8 kVDC1K = 80 VDC2K = 800 VDC  Table 2B – Electronic Industries Alliance (EIA) – AC voltage code table2Q = 125 VAC2T = 250 VAC2S = 275 VAC2X = 280 VAC2F = 300 VACI0 = 305 VACL0 = 350 VAC2Y = 400 VACP0 = 440 VACQ0 = 450 VACV0 = 630 VAC  Table 3 – Capacitor code tablepico-farad (pF)nano-farad (nF)micro-farad (µF) Capacitor Code1 pF capacitor code0.001 nF capacitor code0.000001 µF capacitor code101.5 pF capacitor code0.0015 nF capacitor code0.0000015 µF capacitor code1R52.2 pF capacitor code0.0022 nF capacitor code0.0000022 µF capacitor code2R23.3 pF capacitor code0.0033 nF capacitor code0.0000033 µF capacitor code3R33.4 pF capacitor code0.0039 nF capacitor code0.0000039 µF capacitor code3R93.5 pF capacitor code0.0047 nF capacitor code0.0000047 µF capacitor code4R75.6 pF capacitor code0.0056 nF capacitor code0.0000056 µF capacitor code5R66.8 pF capacitor code0.0068 nF capacitor code0.0000068 µF capacitor code6R88.2 pF capacitor code0.0082 nF capacitor code0.0000082 µF capacitor code8R210 pF capacitor code0.01 nF capacitor code0.00001 µF capacitor code10015 pF capacitor code0.015 nF capacitor code0.000015 µF capacitor code15022 pF capacitor code0.022 nF capacitor code0.000022 µF capacitor code22033 pF capacitor code0.033 nF capacitor code0.000033 µF capacitor code33047 pF capacitor code0.047 nF capacitor code0.000047µF capacitor code47056 pF capacitor code0.056 nF capacitor code0.000056 µF capacitor code56068 pF capacitor code0.068 nF capacitor code0.000068 µF capacitor code68082 pF capacitor code0.082 nF capacitor code0.000082 µF capacitor code820100 pF capacitor code0.1 nF capacitor code0.0001 µF capacitor code101120 pF capacitor code0.12 nF capacitor code0.00012 µF capacitor code121130 pF capacitor code0.13 nF capacitor code0.00013µF capacitor code131150 pF capacitor code0.15 nF capacitor code0.00015 µF capacitor code151180 pF capacitor code0.18 nF capacitor code0.00018 µF capacitor code181220 pF capacitor code0.22 nF capacitor code0.00022 µF capacitor code221330 pF capacitor code0.33 nF capacitor code0.00033 µF capacitor code331470 pF capacitor code0.47 nF capacitor code0.00047 µF capacitor code471560 pF capacitor code0.56 nF capacitor code0.00056 µF capacitor code561680 pF capacitor code0.68 nF capacitor code0.00068 µF capacitor code681750 pF capacitor code0.75 nF capacitor code0.00075 µF capacitor code751820 pF capacitor code0.82 nF capacitor code0.00082 µF capacitor code8211000 pF capacitor code1 / 1n / 1 nF capacitor code0.001 µF capacitor code1021500 pF capacitor code1.5 / 1n5 / 1.5 nF capacitor code0.0015 µF capacitor code1522000 pF capacitor code2 / 2n / 2 nF capacitor code0.002 µF capacitor code2022200 pF capacitor code2.2 / 2n2 / 2.2 nF capacitor code0.0022 µF capacitor code2223300 pF capacitor code3.3 / 3n3 / 3.3 nF capacitor code0.0033 µF capacitor code3324700 pF capacitor code4.7 / 4n7 / 4.7 nF capacitor code0.0047 µF capacitor code4725000 pF capacitor code5 / 5n / 5 nF capacitor code0.005 µF capacitor code5025600 pF capacitor code5.6 / 5n6 / 5.6 nF capacitor code0.0056 µF capacitor code5626800 pF capacitor code6.8 / 6n8 / 6.8 nF capacitor code0.0068 µF capacitor code68210000 pF capacitor code10 / 10n / 10 nF capacitor code0.01 µF capacitor code10315000 pF capacitor code15 / 15n / 15 nF capacitor code0.015 µF capacitor code15322000 pF capacitor code22 / 22n / 22 nF capacitor code0.022 µF capacitor code22333000 pF capacitor code33 / 33n / 33 nF capacitor code0.033 µF capacitor code33347000 pF capacitor code47 / 47n / 47 nF capacitor code0.047 µF capacitor code47368000 pF capacitor code68 / 68n / 68 nF capacitor code0.068 µF capacitor code683100000 pF capacitor code100 / 100n / 100 nF capacitor code0.1 µF capacitor code104150000 pF capacitor code150 / 150n / 150 nF capacitor code0.15 µF capacitor code154200000 pF capacitor code200 / 200n / 200 nF capacitor code0.20 µF capacitor code204220000 pF capacitor code220 / 220n / 220 nF capacitor code0.22 µF capacitor code224330000 pF capacitor code330 / 330n / 330nF capacitor code0.33 µF capacitor code334470000 pF capacitor code470 / 470n / 470nF capacitor code0.47 µF capacitor code474680000 pF capacitor code680 nF capacitor code0.68 µF capacitor code6841000000 pF capacitor code1000 nF capacitor code1.0 µF capacitor code1051500000 pF capacitor code1500 nF capacitor code1.5 µF capacitor code1552000000 pF capacitor code2000 nF capacitor code2.0 µF capacitor code2052200000 pF capacitor code2200 nF capacitor code2.2 µF capacitor code2253300000 pF capacitor code3300 nF capacitor code3.3 µF capacitor code3354700000 pF capacitor code4700 nF capacitor code4.7 µF capacitor code4756800000 pF capacitor code6800 nF capacitor code6.8 µF capacitor code68510000000 pF capacitor code10000 nF capacitor code10 µF capacitor code10615000000 pF capacitor code15000 nF capacitor code15 µF capacitor code15620000000 pF capacitor code20000 nF capacitor code20 µF capacitor code20622000000 pF capacitor code22000 nF capacitor code22 µF capacitor code22633000000 pF capacitor code33000 nF capacitor code33 µF capacitor code33647000000 pF capacitor code47000 nF capacitor code47 µF capacitor code47668000000 pF capacitor code68000 nF capacitor code68 µF capacitor code686100000000 pF capacitor code100000 nF capacitor code100 µF capacitor code107330000000 pF capacitor code330000 nF capacitor code330 µF capacitor code337470000000 pF capacitor code470000 nF capacitor code470 µF capacitor code477680000000 pF capacitor code680000 nF capacitor code680 µF capacitor code6871000000000 pF capacitor code1000000 nF capacitor code1000 µF capacitor code1086.2 Frequently Asked Questions about Capacitor Code1. What is the code of a capacitor?Generally, the actual values of Capacitance, Voltage or Tolerance are marked onto the body of the capacitors in the form of alphanumeric characters. For example, a capacitor can be labeled as, n47 = 0.47nF, 4n7 = 4.7nF or 47n = 47nF and so on. 2.What does the numbers on a capacitor mean?The first two numbers represent the value in picofarads, while the third number is the number of zeroes to be added to the first two. For example, a 4.7 μF capacitor with a voltage rating of 25 volts would bear the marking E476. 3.What is the value of a capacitor?Capacitor values can be of over 109 range, and even more as super capacitors are now being used. To prevent confusion with large numbers of zeros attached to the values of the different capacitors the common prefixes pico (10 -12 ), nano (10 -9) and micro (10 -6) are widely used. 4.How can you determine the value of a capacitor?The value of capacitors can be determined by several ways depending up on the type of capacitor like electrolytic, disc, film capacitors, etc. These methods include value or number printed on the body of the capacitor or color coding of the capacitor. 5.How can I determine the capacitance of an unknown capacitor?To determine an unknown capacitance using an oscilloscope , a dc power source such as a 9-V battery, a known resistance, a switch and the capacitor are all connected in series. An oscilloscope probe tip and ground lead are connected across the capacitor. Additionally, you need a short wire jumper to shunt across the capacitor. Ⅶ Capacitor Code Calculator7.1 Capacitor Safety Discharge Calculator ToolThis Capacitor Safety Discharge Calculator helps to determine the discharge rate of a capacitor at known capacitance and charge through a fixed-value resistor. Enter the initial voltage, time, resistance, and capacitance into the calculator. The calculator will display the total voltage discharged and remaining. Many factors need to be considered when choosing a discharge resistor. Safety standards require the voltage across a capacitor to reach a safe voltage before a person is able to touch it. In the USA, standards such as UL, OSHA, NTA, ETL, MET, etc. will have the requirements available for the needs of your product.Capacitor Safety Discharge Calculator Tool 7.2 Series and Parallel Capacitance CalculatorThis tool calculates the overall capacitance value for multiple capacitors connected either in series or in parallel.Series and Parallel Capacitance Calculator 

IntroductionIn 2025, while surface mount technology (SMT) dominates mass production, the ability to read resistor color codes remains a fundamental skill for electronics prototyping, repairs, and education. Color bands are used to identify leaded resistors, typically with a power rating of up to one watt. The international standard IEC 60062 specifies this coding system, which applies to both resistors and capacitors.This system allows engineers and hobbyists to quickly identify resistance values without a multimeter. While digital marking codes are common on SMD resistors, the color band system remains the global standard for through-hole components.Figure: A guide to the resistor color code standard. Several bands provide the complete data for the component. They indicate the resistance value, tolerance, and sometimes the failure rate (reliability). Resistors typically have between three and six bands. The first two (or three) bands represent the significant digits of the resistance value, followed by a multiplier band. Resistance levels are standardized into specific series (E-series) of preferred values.Video: Visual guide to understanding resistor color codes.Ⅰ 1 Ohm Resistor Color Code1.1 Color Code Of 1 Ohm 4-Band ResistorThe resistor color code table is used to determine the value. Below is the breakdown for a 1 Ohm, 4-band resistor:Figure: Color code of 1Ω 4-band resistor.BandColorValue1st BandBrown 12nd BandBlack 03rd Band (Multiplier)Gold x 0.14th Band (Tolerance)Gold ±5%Calculation1st digit: 12nd digit: 0Multiplier: 0.11 OhmTolerance: ±5% Calculation logic:1st-band = Brown = 1 (1st digit)2nd-band = Black = 0 (2nd digit)3rd-band = Gold = 0.1 (Multiplier)4th-band = Gold = ±5% (Tolerance) Formula: $10 \times 0.1 = 1 \Omega$.Tolerance range: 5% of 1Ω is 0.05Ω. Theoretically, the actual resistance of a 1Ω resistor lies between 0.95Ω and 1.05Ω. Note on Low Values: For low-value resistors (under 10 Ohms), the multiplier band is often Gold (x0.1) or Silver (x0.01). In modern IEC 60062 standards, a Pink band is sometimes used for x0.001 multipliers in high-precision shunts. In 4- and 5-band resistors, the last band indicates tolerance. Gold indicates ±5%, Silver ±10%, Brown ±1%, and Red ±2%. If the fourth band is missing, the tolerance is standardized at ±20% (rare in 2025). 1.2 Color Code Of 1 Ohm 5-Band ResistorThe 1 Ohm 5-band resistor color code is Brown, Black, Black, Silver, Black:Figure: Color code of 1Ω 5-band resistor.1st-band = Brown = 1 (1st Digit)2nd-band = Black = 0 (2nd Digit)3rd-band = Black = 0 (3rd Digit)4th-band = Silver = x 0.01 (Multiplier)5th-band = Black = ±1% (Tolerance) For a 1 Ohm 5-band precision resistor, the calculation is $100 \times 0.01 = 1 \Omega$. The tighter tolerance (Black band = 1%) makes these ideal for current sensing applications. 1.3 Frequently Asked Questions about 1 Ohm Resistor1. What does a 1 ohm resistor do?A 1 Ohm resistor is often used as a current sense resistor (shunt) to measure current flow or to simulate a specific load. In power supplies, it can also act to simulate the ESR (Equivalent Series Resistance) of a large capacitor. 2. What is the definition of 1 ohm?The Ohm is the SI unit of electrical resistance. 1 Ohm is defined as the resistance between two points of a conductor when a constant potential difference of 1 volt applied between these points produces a current of 1 ampere. 3. Is 1 ohm a lot of resistance?No, 1 Ω is a very small amount of resistance. It is close to a short circuit. Resistances in electronic circuits usually range from hundreds (Ohms) to millions (Megaohms). 4. What is the formula for resistance?Rearranging Ohm's Law ($V = I \times R$) gives $R = V / I$. Therefore, 1 Ohm = 1 Volt per Ampere. Ⅱ 10 Ohm Resistor Color Code2.1 Color Code of 10 Ohm 4-Band ResistorThe 4-band 10 Ohm resistor color code is shown below:Figure: Color code of 10Ω 4-band resistor. BandColorValue1st BandBrown 12nd BandBlack 03rd Band (Multiplier)Black x 1 ($10^0$)4th Band (Tolerance)Gold ±5% Calculation:1st band = Brown = 12nd band = Black = 03rd band = Black = Multiplier $10^0$ = 1Result: $10 \times 1 = 10 \Omega$.With ±5% tolerance (0.5Ω), the actual value lies between 9.5Ω and 10.5Ω. Pro Tip: Be careful not to confuse Brown (1st band) and Red bands under poor lighting, as a "Red-Black-Black" sequence would read 20 Ohms. 2.2 Frequently Asked Questions about 10 Ohm Resistor1. What is the power consumed by a 10 ohm resistor with no current?If no current flows (open circuit), the power consumed is zero. 2. What is the current through a 10 ohm resistor in a circuit?Current depends on voltage. For example, if a 10 Ohm resistor is connected to a 6V source with some internal resistance (total circuit resistance 10.8Ω), the current is $I = V/R = 6 / 10.8 \approx 0.55$ Amps. 3. What is the voltage across the 10 ohm resistor?Ohm's Law states $V = I \times R$. If 1.2 Amps flows through a 10 Ohm resistor, the voltage drop is $1.2 \times 10 = 12$ Volts. 4. How much power is dissipated by a 10 ohm resistor?Power is calculated as $P = I^2R$ or $P = V^2/R$.Example: If 12 Volts is applied directly across a 10 Ohm resistor, the current is 1.2A. The power is $P = 1.2^2 \times 10 = 14.4$ Watts. Warning: A standard 1/4 Watt resistor would burn instantly in this scenario. You would need a high-power ceramic resistor. 5. What is a 10 ohm resistor used for?Low-value resistors like 10 Ohms are often used as current limiters in power circuits, in voltage dividers, or as part of RC filters (snubbers) to suppress voltage spikes. Ⅲ 100 Ohm Resistor Color Code3.1 Color Code of 100 Ohm 4-Band ResistorFor a 100 Ohm resistor, the bands are Brown, Black, Brown, Gold.Figure: Color code of 100Ω 4-band resistor. BandColorValue1st BandBrown12nd BandBlack03rd Band (Multiplier)Brownx 10 ($10^1$)4th Band (Tolerance)Gold±5% Calculation:1st digit (Brown) = 12nd digit (Black) = 0Multiplier (Brown) = 10Result: $10 \times 10 = 100 \Omega$.With ±5% tolerance, the resistance ranges from 95Ω to 105Ω. 3.2 Color Code of 100 Ohm 5-Band ResistorA 5-band 100 Ohm resistor allows for higher precision. The sequence is Brown, Black, Black, Black, Gold (or Brown/Red for tolerance).Figure: Color code of 100Ω 5-band resistor.1st-band = Brown = 12nd-band = Black = 03rd-band = Black = 04th-band (Multiplier) = Black = x 1 ($10^0$)5th-band (Tolerance) = Gold (±5%)Calculation: $100 \times 1 = 100 \Omega$. 3.3 Frequently Asked Questions about 100 Ohm Resistor1. What is a 100 ohm resistor used for?It is commonly used for LED protection, gate drive resistance in MOSFET circuits, and signal termination. It fits perfectly into breadboards for prototyping. 2. How can you tell if a resistor is 100 ohm?Look for the color bands: Brown-Black-Brown (4-band) or Brown-Black-Black-Black (5-band). 3. What is the value of 100 ohm in Megaohms?100 Ohms is $0.0001 M\Omega$ ($100 \times 10^{-6}$). 4. What is the actual range of a 100 ohm resistor?With standard ±5% tolerance, it measures between 95Ω and 105Ω. An older ±20% resistor (rare today) would measure between 80Ω and 120Ω. Ⅳ 120 Ohm Resistor Color Code4.1 Color Code of 120 Ohm 4-Band ResistorThe 120 Ohm resistor is famously used in CAN Bus termination. The color code is Brown, Red, Brown, Gold.Figure: Color code of 120Ω 4-band resistor. BandColorValue1st BandBrown12nd BandRed23rd Band (Multiplier)Brownx 104th Band (Tolerance)Gold±5% Calculation:Digits: 1, 2Multiplier: x 10Result: $12 \times 10 = 120 \Omega$.Tolerance range (±5%): 114Ω to 126Ω. 4.2 Frequently Asked Questions about 120 Ohm Resistor1. Why is 120 Ohm the standard for CAN Bus?The characteristic impedance of twisted pair cables used in automotive CAN networks is approximately 120 Ohms. Placing a 120Ω resistor at each end of the bus prevents signal reflections (ringing), ensuring data integrity. 2. Where do you place the 120 Ohm resistor?It is placed between CAN High (pin 7) and CAN Low (pin 2) at the two physical ends of the bus network. 3. Can I measure 120 Ohms on a live CAN bus?If the system is powered down, measuring resistance between CAN High and CAN Low should yield 60 Ohms. This is because there are two 120Ω terminating resistors in parallel ($120 / 2 = 60$). Ⅴ 150 Ohm Resistor Color Code5.1 Color Code of 150 Ohm 4-Band ResistorThe sequence for 150 Ohms is Brown, Green, Brown, Gold.Figure: Color code of 150Ω 4-band resistor. BandColorValue1st BandBrown12nd BandGreen53rd Band (Multiplier)Brownx 104th Band (Tolerance)Gold±5% Calculation:Digits: 1, 5Multiplier: x 10Result: $15 \times 10 = 150 \Omega$.Tolerance range: 142.5Ω to 157.5Ω. 5.2 Frequently Asked Questions about 150 Ohm Resistor1. How do I identify a 150 ohm resistor?Look for the Green band in the second position (representing 5) and the Brown band in the third position (representing x10 multiplier). Ⅵ 220 Ohm Resistor Color Code6.1 220 Ohm Resistor Color Code (5% Tolerance)This is extremely common for driving LEDs from 5V logic.Figure: 220 ohm resistor color code (Red-Red-Brown-Gold). BandColorValue1st BandRed22nd BandRed23rd Band (Multiplier)Brownx 104th Band (Tolerance)Gold±5% Calculation:Digits: 2, 2Multiplier: x 10Result: $22 \times 10 = 220 \Omega$. 6.2 220 Ohm Resistor Color Code (10% Tolerance)If the last band is Silver, the tolerance is ±10%. This means the resistor could be anywhere between 198Ω and 242Ω. 6.3 Frequently Asked Questions about 220 Ohm Resistor1. What does a 220 ohm resistor do?It resists current flow. In 2025, it is the standard "go-to" resistor for limiting current to standard LEDs when powered by USB (5V) or microcontrollers like Arduino or ESP32. 2. Will a 5 volt LED with a 220 ohm resistor run safely?Yes. If a red LED drops 2.0V, the resistor drops the remaining 3.0V. Using Ohm's Law ($I = V/R$), $3.0V / 220\Omega \approx 13.6 mA$, which is a safe and bright current for most indicator LEDs. Power dissipation is minimal ($0.04W$), so a 1/8W or 1/4W resistor is perfect. Ⅶ 330 Ohm Resistor Color Code7.1 Color Code of 330 Ohm 4-Band ResistorSequence: Orange, Orange, Brown, Gold.Figure: Color code of 330Ω 4-band resistor. BandColorValue1st BandOrange32nd BandOrange33rd Band (Multiplier)Brownx 104th Band (Tolerance)Gold±5% Calculation:Digits: 3, 3Multiplier: x 10Result: $33 \times 10 = 330 \Omega$. 7.2 Frequently Asked Questions about 330 Ohm Resistor1. Why use a 330 ohm resistor for an LED?If you need slightly less brightness or are using a 3.3V power supply (common in modern electronics like Raspberry Pi), a 330Ω resistor offers a good balance of brightness and protection. 2. What is the real value of a 330 ohm resistor?With 5% tolerance, it falls between 313.5Ω and 346.5Ω. Ⅷ 470 Ohm Resistor Color Code8.1 Color Code of 470 Ohm 4-Band ResistorSequence: Yellow, Violet, Brown, Gold.Figure: Color code of 470Ω 4-band resistor. BandColorValue1st BandYellow42nd BandViolet73rd Band (Multiplier)Brownx 104th Band (Tolerance)Gold±5% Calculation:Digits: 4, 7Multiplier: x 10Result: $47 \times 10 = 470 \Omega$. 8.2 Frequently Asked Questions about 470 Ohm Resistor1. What is a 470 ohm resistor used for?It is often used to drive blue or white LEDs (which have higher forward voltages) from higher voltage sources like 9V batteries or 12V automotive systems. 2. How do I know if I have a 470 ohm resistor?Look for the distinct Yellow (4) and Violet (7) starting bands. Ⅸ 500 (510) Ohm Resistor Color Code9.1 Color Code of 510 Ohm 4-Band ResistorNote: 500 Ohms is not a standard "E24 series" value. The closest standard value is 510 Ohms. In 99% of circuits, a 510Ω resistor is a perfect substitute for a 500Ω requirement.Figure: Color code of 510Ω 4-band resistor (Green-Brown-Brown-Gold). BandColorValue1st BandGreen52nd BandBrown13rd Band (Multiplier)Brownx 104th Band (Tolerance)Gold±5% Calculation:Digits: 5, 1Multiplier: x 10Result: $51 \times 10 = 510 \Omega$. 9.2 Frequently Asked Questions about 510 Ohm Resistor1. Can you substitute 500 ohm for 510 ohm?Yes. The error is only 2%. Given that standard resistors have a 5% tolerance, 510 Ohms is well within the acceptable range for a "500 Ohm" design. Alternatively, you can place two 1kΩ resistors in parallel to get exactly 500Ω. Ⅹ 1k Ohm Resistor Color Code10.1 Color Code of 1k Ohm 4-Band ResistorThe 1kΩ (1000 Ohm) resistor is arguably the most common resistor in electronics, used extensively for pull-up and pull-down logic circuits.Figure: Color code of 1kΩ 4-band resistor (Brown-Black-Red-Gold). BandColorValue1st BandBrown12nd BandBlack03rd Band (Multiplier)Redx 100 ($10^2$)4th Band (Tolerance)Gold±5% Calculation:Digits: 1, 0Multiplier: Red = x 100Result: $10 \times 100 = 1000 \Omega = 1 k\Omega$. 10.2 Frequently Asked Questions about 1k Ohm Resistor1. What is a 1k ohm resistor used for?It is the industry standard for pull-up resistors on microcontroller pins (like Arduino inputs) to prevent floating signals. 2. What is 1k ohm?"k" stands for Kilo (1000). Thus, 1k Ohm is 1000 Ohms. Ⅺ 2k Ohm Resistor Color Code11.1 Color Code of 2k Ohm 4-Band ResistorSequence: Red, Black, Red, Gold.Figure: Color code of 2kΩ 4-band resistor. BandColorValue1st BandRed22nd BandBlack03rd Band (Multiplier)Redx 1004th Band (Tolerance)Gold±5% Calculation:Digits: 2, 0Multiplier: Red = x 100Result: $20 \times 100 = 2000 \Omega = 2 k\Omega$. Ⅻ 2.2k Ohm Resistor Color Code12.1 Color Code of 2.2k Ohm 4-Band ResistorFamous for the "Three Reds" pattern.Figure: Color code of 2.2kΩ 4-band resistor (Red-Red-Red-Gold). BandColorValue1st BandRed22nd BandRed23rd Band (Multiplier)Redx 100 ($10^2$)4th Band (Tolerance)Gold±5% Calculation:Digits: 2, 2Multiplier: Red = x 100Result: $22 \times 100 = 2200 \Omega = 2.2 k\Omega$. 12.2 Frequently Asked Questions about 2.2k Ohm Resistor1. What does a 2.2k resistor do?It is commonly used in voltage dividers, particularly with LDRs (Light Dependent Resistors) to read ambient light levels with a microcontroller. 2. Calculating Current for a 1/2 Watt 2.2k ResistorIf you have a 1/2 Watt (0.5W) resistor, the maximum current it can handle is calculated using the power formula $P = I^2 \times R$.Rearranging for current ($I$):$I = \sqrt{P / R}$$I = \sqrt{0.5 / 2200}$$I \approx 0.015$ AmperesConclusion: A 2.2kΩ 1/2W resistor can safely handle approximately 15 milliamperes (mA). XIII Resistor Color Code Calculator13.1 4 Band Resistor Color Code CalculatorNeed to double-check your work? Use this tool to instantly decode 4-band axial lead resistors. Open 4 Band Resistor Color Code Calculator13.2 5 Band Resistor Color Code CalculatorFor high-precision 5-band resistors, use the calculator below: Open 5 Band Resistor Color Code Calculator 13.3 6 Band Resistor Color Code CalculatorIncludes the 6th band for Temperature Coefficient (PPM). Open 6 Band Resistor Color Code Calculator

Ⅰ IntroductionA shunt is an electrical device that creates a low-resistance route for a current to flow through. This allows the current to flow to a different part of the circuit. Ammeter shunts and current shunt resistors are two terms for shunts. A shunt resistor is used to measure alternating or direct electric current. The voltage drop across the resistor is used to determine this. Shunt resistors were once used to describe a resistor connected in parallel to an ammeter as a shunt to increase the current measurement range, but in recent years, all resistors used to detect circuit current have been referred to as shunt resistors (current sense shunt resistor). This vedio shows a shunt resistor CatalogⅠ IntroductionⅡ What Does a Shunt Resistor Do?Ⅲ How Does a Shunt Resistor Work?Ⅳ How to Measure Current by a Shunt Resistor?Ⅴ Position of the Shunt Resistor in the Circuit When Measuring CurrentⅥ How to Select a Shunt Resistor?6.1 How to Calculate Shunt Resistance?6.2 Shunt Resistor ParametersⅦ How to Wire a Shunt Resistor?Ⅷ Frequently Asked Questions about Shunt Resistor Ⅱ What Does a Shunt Resistor Do?The electrical shunt is a device that creates a low-resistance route that allows electricity to travel through or be redirected past a defined point in a circuit. Some meters have built-in precision current shunts that allow measurements in terms of DC and Watts to be taken. Electrical shunts can also be used to measure the flow of DC. The formula for Ohm's law is as follows: V = I × R This equation applies to the voltage (V) created across the resistance (R in ohms) as a function of the resistance and the current (I in amps) flowing through it. A current shunt with a resistance of 0.002 ohms and a current of 30 amps, for example, will generate 0.002 x 30 = 0.06 volts or 60 millivolts (milliVolts). By including a current shunt into a measurement circuit, you can determine the voltage drop across the shunt. The calculation of current measurement using Ohm's law will be possible thanks to the assessment of current shunt resistance. The current shunt resistance can also be calibrated using Ohm's law. Shunt resistors are commonly used in the following applications:Current circulating through a battery is measured, and power output is monitored.Before the signal reaches the circuit elements, high-frequency noise is redistributed (this requires a shunt with a capacitator).Installation in a DC connects the container with a negative conductor connecting the batteries to the inverter.Control equipment, such as battery chargers and power sources, provides overload protection. Ⅲ How Does a Shunt Resistor Work?The technological limits of a shunt resistor differ from those of a conventional resistor. Shunt resistors allow for high precision while maintaining a low ohmic value. To reach such great precision, a Kelvin connection is recommended. This connection eliminates difficulties like lead sensitivity and resistance. The value of a shunt resistor can be influenced by several reversible and irreversible causes. Long-term stability and irreversible change in resistance are ensured by the accompanying mechanical, electrical, and thermal stresses. The Temperature Coefficient of Resistance (TCR) is measured in ppm/ and represents the drift caused by the transistor cooling or heating due to changes in ambient temperature. The Power Coefficient of Resistance (PCR) or ppm/W is used to express the amount of power that the resistor must dissipate. Electrical shunts are commonly used to safeguard the speed controller from a load that consumes too much current or to limit the motor's speed. By disconnecting the shunt from the sense line, the controller's speed can be increased. After that, the sense line must be linked to the ground. Because there will be no voltage drop, the speed controller will generate the maximum amount of power feasible. However, if the load on the controller transistors is too great, this could be dangerous. A high-precision current shunt can also be utilized for equipment bench testing. This current shunt can be used in conjunction with a voltmeter to determine the amount of current flowing through the circuit. The use of a sensitive voltmeter ensures a high level of safety in the measurement of greater currents than can be achieved with a regular multimeter. Ⅳ How to Measure Current by a Shunt Resistor?An ammeter is a device that measures electric current. The voltage drop across a precision resistor with a known resistance is measured by most modern ammeters. Ohm's law is used to calculate current flow:  To measure current, most ammeters feature a built-in resistor. When the current is too high for the ammeter, however, a different configuration is required. The solution is to connect the ammeter to a precise shunt resistor in parallel. Ammeter shunt is a name that is sometimes used to describe this sort of resistor. This is usually a low resistance manganin resistor with great accuracy. Only a small (known) amount of the current travels through the ammeter after it is divided between the shunt resistor and the ammeter. The remaining current travels through the shunt resistor, bypassing the ammeter. Large currents can still be measured this way. The actual amperage can be measured by accurately scaling the ammeter. The greatest amperage that can be measured using this arrangement is theoretically limitless. However, the measurement device's voltage rating must not be exceeded. As a result, the maximum current multiplied by the ammeter resistance value cannot exceed the voltage rating. To minimize circuit interference, the ammeter resistance should be as low as feasible. A smaller ammeter, on the other hand, creates a smaller voltage drop, which results in a lesser resolution. Example of calculationA series resistor in an ammeter, for example, is a shunt resistor with a resistance of 1 mΩ. A voltage drop of 30 mV is observed across the resistor after it is inserted in a circuit. The current is equal to the voltage divided by the resistance in this case, or:I=V/R=0.030/0.001=30A. With the resistance value unknown and the voltage and current known, the same calculation might be performed. This is how shunt resistance is measured. Ⅴ Position of the Shunt Resistor in the Circuit When Measuring CurrentA.To eliminate the common-mode voltage, the shunt is frequently put on the grounded side. However, there are certain drawbacks.B.The common-mode voltage may be too high for the ammeter in this arrangement. Position of the Shunt Resistor in the Circuit The placement of the shunt resistor in the circuit must be carefully considered. When the circuit and the measurement instrument share a common ground, the shunt is frequently put as close to the ground as practicable. The rationale for this is to safeguard the ammeter from excessive common-mode voltage, which could harm the instrument or cause incorrect results. One downside of this configuration is that leakage currents through the shunt may go undetected. To protect the instrument, the shunt must be isolated from the ground or incorporate a voltage divider or an isolation amplifier if it is put in the ungrounded leg. Other options include employing a Hall Effect sensor instead of directly attaching the measurement instrument to the high voltage circuit. Current shunts, on the other hand, are frequently cheaper. Ⅵ How to Select a Shunt Resistor?Shunt resistors are a type of resistor that creates a low resistance route. Because of their low resistance, they are commonly employed to detect high currents. Many applications necessitate current measuring. Overcurrent protection, 4-20mA systems, battery chargers, high-brightness LED control, H-bridge motor control, and metrology, for example, all require current monitoring. Shunt sensors are simpler to develop and less expensive than magnetic current sensors. They do not, however, afford any seclusion. A Rogowski coil, also known as a Hall effect sensor, is a noninvasive measurement in which the detecting circuitry is not electrically coupled to the monitored system and subsequently isolated. 6.1 How to Calculate Shunt Resistance?Shunt resistors have different technological limits than normal resistors. They have a low ohmic value and are high-precision resistors (they can be expressed in microOhm when several hundreds of Amper currents must be measured). Because accuracy is crucial, current sensing is best accomplished via a Kelvin connection (or four-terminal connection), which eliminates the undesired effects of lead resistance and temperature sensitivity. Four-terminal connection equation A shunt resistor's value can be changed by a variety of causes, which are divided into reversible and irreversible effects. A change in resistance that is irreversible owing to mechanical, electrical, or thermal stresses is referred to as long-term stability. There are two fundamental components to reversible effects:Temperature Coefficient of Resistance (TCR): TCR is measured in parts per million and describes how the resistor drifts as the ambient temperature changes.The Power Coefficient of Resistance (PCR) is a unit of measurement for the amount of power a resistor must dissipate. It is given in ppm/W. 6.2 Shunt Resistor ParametersThe thermal EMF is an important metric for shunt resistors that isn't as critical for ordinary resistors. A voltage changeable with temperature appears at the junction of two different conducting materials (explaining why it's termed thermal EMF or thermocouple effect and expressed in µV/). An intermetallic junction's rate of change of voltage with temperature is a function of the metallic combination. Depending on whether side of the combination is regarded as the input, the voltage produced is either positive or negative. All resistors are assumed to be soldered to copper at some point, and copper becomes the reference metal. Some Thermal EMF values are shown in the table below. Table 1: Thermal EMF of the Metal vs. CopperMetal / AlloyThermal EMF vs copper in μV/°CEvanohm2Cupron-45Manganin-3Zeranin-1.3Nickel-22Gold0.2Silver-0.2Aluminum-4 Table 2. TCR, ppm/  of various Resistor Element MaterialsTemperature range-55°C to +25°C0°C to +25°C+25°C to +60°C+25°C to +125°CManganin5010-5-80Zeranin20±2.5±510Evanohm52.5-2.5-5Foil (Vishay proprietary)-1-0.30.31Thin Film-10-5510Thick Film-100-2550100 Manganin is the preferred material for shunts with exposed blades based on thermal EMF, TCR, and cost. Zeranin, a cousin of Manganin with a lower temperature coefficient, is used to make shunts with exposed parallel wires. Evanohm, which has a near-zero temperature coefficient and a high sensitivity to strain, is commonly used to make shunts contained in heat sinks. Ⅶ How to Wire a Shunt Resistor?First, read and follow any manufacturer's instructions. It will be required to make sure that the ammeter and the shunt can handle the same mV levels. The shunt must then be connected to the negative connection that runs from the battery bank to the electrical circuits. Following the negative lead from the battery to the circuits or fuse box will reveal this. Adjust the negative connections on the battery to the corresponding side of the battery and shunt if you want to measure the current consumed by the connected device and supplied by the alternator. The other side of the shunt should be linked to the battery's negative terminal with a sufficiently thick cable. The shunt resistor must be installed in a location where there is no possibility of shorting cables. The negative cables can be shortened to make the installation process easier. It is also necessary to drill a suitable hole for the ammeter to mount on the panel. The hole must be large enough to connect the meter firmly. The plus and minus pins on the connection between the leads and the DC  or voltage should be properly fitted. You must also confirm that the meter is correctly set (the current can be measured in AC, DC, ohms etc). The wiring procedure should start with a simple check to confirm that the shunt is connected to the load in series. You'll also need to hook up a battery pack and make sure it's linked to the right side of the shunt. The wiring from the shunt should then be fed to the load. The ammeter and the ground should not be connected in any way. The ammeter, on the other hand, should be wired in parallel with the shunt, with the shunt connected to the load in series. The powering of the circuit should be the first step in measuring the current or voltage. After that, you can take the meter reading. When measuring the level of resistance, however, you should not turn on the electricity. Ⅷ Frequently Asked Questions about Shunt Resistor1.What is the meaning of shunt resistor？A resistor having a very low value of resistance such type of resistor is called shunt resistance. The shunt is used in the galvanometer for measuring the large current. It is connected in parallel to the circuit of the galvanometer. 2.Why is it called a shunt resistor?In electronics, a shunt is a device that creates a low-resistance path for electric current, to allow it to pass around another point in the circuit. The origin of the term is in the verb 'to shunt' meaning to turn away or follow a different path. 3.Why a shunt resistor is connected in parallel?A shunt resistor is connected in parallel to the galvanometer so as to keep the resistance low. Such low resistance galvanometer is used in series with the circuit to measure the strength of current through the circuit. 

Ⅰ IntroductionA Colpitts oscillator is one of several designs for LC oscillators, which employ a combination of inductors (L) and capacitors (C) to produce an oscillation at a specific frequency. It was invented in 1918 by American engineer Edwin H. Colpitts. The voltage divider made up of two capacitors in series across the inductor serves as feedback for the active device in the Colpitts oscillator.   CatalogⅠ IntroductionⅡ What a Colpitts Oscillator Contains?Ⅲ How the Colpitts Oscillator Works?Ⅳ Colpitts Oscillator vs Hartley OscillatorⅤ Types of Colpitts Oscillator5.1 Common Base Colpitts Oscillator5.2 Common Emitter Colpitts Oscillator5.3 Buffered Colpitts OscillatorⅥ Advantages of Colpitts OscillatorⅦ Applications of Colpitts OscillatorⅧ ConclusionⅨ Frequently Asked Questions about Colpitts OscillatorⅡ What a Colpitts Oscillator Contains?The Colpitts circuit, like other LC oscillators, is made up of a gain device (such as a bipolar junction transistor, field-effect transistor, operational amplifier, or vacuum tube) with its output connected to its input in a feedback loop containing a parallel LC circuit (tuned circuit) that serves as a bandpass filter to set the oscillation frequency. The amplifier's input and output impedances will be different, and these must be linked into the LC circuit without overdamping it. Ⅲ How the Colpitts Oscillator Works?The Colpitts oscillator is commonly used in RF applications, with a frequency range of 20KHz to 300MHz. The capacitive voltage divider configuration in the tank circuit serves as the feedback source in the Colpitts oscillator, and this arrangement provides superior frequency stability than the Hartley oscillator, which uses an inductive voltage divider system for feedback. The circuit diagram of a typical transistor-based Colpitts oscillator is shown below. Colpitts oscillator The resistors R1 and R2 in the circuit schematic provide a voltage divider biasing for the transistor. The transistor's collector current is limited by the resistor R4. The input DC decoupling capacitor is Cin, and the output decoupling capacitor is Cout. The emitter resistor, Re, is used to ensure thermal stability. The emitter by-pass capacitor is denoted by Ce. The emitter by-pass capacitor's job is to keep the amplified AC signals from crossing Re. If the emitter by-pass capacitor is missing, the amplified AC signal will drop across Re, causing the transistor's DC biasing conditions to change, resulting in lower gain. The tank circuit is made up of capacitors C1, C2, and inductor L1. Tank circuit in a Colpitts oscillator When the power source is turned on, the capacitors C1 and C2 begin to charge. They start discharging through the inductor L1 when they are completely charged. The electrostatic energy stored in the capacitors is transmitted to the inductor as magnetic flux when the capacitors are fully drained. The inductor begins to discharge and the capacitors are re-charged. Oscillation is caused by energy being transferred back and forth between capacitors and inductors. The voltage across C2 is in phase opposite that of C1, and the voltage across C2 is sent back to the transistor. The enhanced feedback signal at the transistor's base emerges across the collector and emitter. The transistor compensates for the energy lost in the tank circuit, maintaining the oscillations. One 180° phase shift is produced by the tank circuit, and the other 180° phase shift is produced by the transistor. That means the input and output are in phase, and positive feedback requires to keep oscillations going for long periods. The equation below can be used to calculate the frequency of the Colpitts oscillator's oscillations. Where L is the inductance of the tank circuit's inductor and C is the effective capacitance of the tank circuit's capacitors. The effective capacitance of the serial combination C= (C1C2)/(C1+C2) if C1 and C2 are independent capacitances. The Colpitts oscillator can be made variable by utilizing ganged variable capacitors in place of C1 and C2. Ⅳ Colpitts Oscillator vs Hartley OscillatorThe Colpitts oscillator is extremely similar to the Hartley oscillator, however they are constructed differently. The Colpitts oscillator employs a single inductor in parallel with two capacitors in series, whereas the Hartley oscillator utilizes the exact opposite, one single capacitor in parallel with two inductors in series. In high-frequency operation, the Colpitts oscillator is more stable than the Hartley oscillator. Colpitts Oscillator vs Hartley Oscillator In high-frequency operation, the Colpitts oscillator is an ideal choice. It can generate output frequencies in the Megahertz and Kilohertz ranges. Ⅴ Types of Colpitts Oscillator5.1 Common Base Colpitts OscillatorA typical Colpitts oscillator design is shown below. The Colpitts LC tank circuit operates similarly to the Hartley oscillator, however it only has a single inductor and two capacitors. Instead of the tapped inductor used in the Hartley, the capacitors create a single 'tapped' capacitor. The total capacitance in series (CTOT) of the two capacitors (connected in series) is calculated as follows: common base Colpitts oscillator The total capacitance required for the tank circuit to achieve parallel resonance at the specified frequency is given. The oscillation frequency is calculated using the same formula as the Hartley oscillator. However, in this case, the number C is the sum of the values C2 and C3 in order (CTOT). C2 and C3's values are chosen so that their ratio delivers the required proportion of feedback signal. The ratio of voltages across two capacitors in series, on the other hand, is inversely proportional to the ratio of their values, implying that the smaller capacitor has a higher signal voltage across it. The fundamental advantage of the Colpitts design is that the single inductor in the tuned circuit eliminates any mutual inductance between two coils, where the alternating magnetic field generated up around one inductor drives a current into the inductor of the other coil. This alters the resonance frequency of the tuned circuit by changing the total inductance of the coils. 5.2 Common Emitter Colpitts OscillatorThe Colpitts analog of the Common Emitter Hartley Oscillator is shown below.                              common emitter Colpitts oscillator It employs a common emitter amplifier, and because the tuned (tank) circuit tapping point is connected to the ground in this design, the tank circuit generates anti-phase waves at the top and bottom of L2, ensuring proper phase relationships for positive feedback between collector and base. The feedback is delivered to the base via C1, which also functions as a DC block, preventing the greater voltage on L1 from causing the base bias voltage to be thrown off. The supply rail (+Vcc) is connected to the tank circuit (L2, C2, and C3) through L1. Because the DC supply is significantly decoupled by huge capacitors in the DC Power supply, if the tank circuit were connected directly to the supply, there would be no anti-phase AC signal present at the top of the tank circuit. As a result, between the tuned circuit and the supply, an RF choke (L1) with a high impedance at the oscillation frequency is provided. This permits the development of a signal voltage across L1 for feedback purposes. Automatic class C bias is utilized, with the emitter only partially disconnected by a small amount of C5 to provide the previously mentioned "slide bias." The Colpitts oscillator, like the Hartley, can produce an excellent sine wave shape and has the added benefit of improved stability at very high frequencies. It's easy to spot because it's always got a "tapped capacitor" on it. The fact that any load placed on the output by circuits that the output is supplying essentially inserts a dampening resistance across the tank circuit complicates the design of a sine wave oscillator. This can have an adverse influence on both the wave shape and frequency stability of the oscillator waveform, as well as lowering the amplitude of the oscillator output by lowering the Q factor of the tuned tank circuit. 5.3 Buffered Colpitts OscillatorAs demonstrated below, feeding the oscillator output into an emitter follower buffer amplifier is a standard technique. buffered Colpitts oscillator TR1's load impedance has been changed to the RF choke, and the tank circuit is now isolated from TR1 by two DC blocking capacitors, C1 and C4. As a result, instead of a tuned amplifier, this variant of the Colpitts oscillator uses a tuned feedback channel. The emitter follower stage (R4, TR2 and R5) has a very high input impedance, which has no effect on the oscillator, and a very low output impedance, which allows it to drive loads with impedances as low as a few tens of ohms. Variations in supply voltage can also affect the frequency stability of oscillators. When good frequency stability is required, it is typical to use a stabilized power supply. Extra decoupling capacitors may be required for oscillator supplies to reduce undesired 'noise.' Automatic class C bias, which is given in this circuit by only partially disconnecting the emitter of TR1 by C5, is generally used to achieve stable amplitude. Ⅵ Advantages of Colpitts OscillatorThe Colpitts oscillator may produce very high-frequency sinusoidal pulses.It can tolerate extreme heat and cold.There is a lot of frequency stability.Both variable capacitors can be used to change the frequency.A small number of components is all that is required.Over a certain frequency range, the output amplitude remains constant.The Colpitts oscillator was created to address the shortcomings of the Hartley oscillator and is known to have no unique flaws. As a result, a Colpitts oscillator has a wide range of uses. Ⅶ Applications of Colpitts OscillatorThe Colpitts oscillator is mostly employed for fixed frequency generation due to the challenges in achieving a smooth variation of inductor and capacitor.The Colpitts oscillator is most commonly found in mobile phones and other radio frequency-controlled communications devices.The Colpitts oscillator is a great choice for high-frequency oscillation. Colpitts Oscillator is used in high-frequency oscillator-based systems.Colpitts Oscillator is utilized in a few applications where continuous and undamped oscillation is required as well as thermal stability.For applications that require a broad range of frequencies with minimal noise.Colpitts oscillator is used in a variety of SAW-based sensors.The Colpitts oscillator is used in a variety of metal detectors.A Colpitts oscillator is used in frequency modulation radio frequency transmitters.It has a wide range of uses in both military and commercial items.Signal masking-related chaotic circuits are also required in microwave applications Colpitts oscillator in various frequency ranges. Ⅷ ConclusionTo summarise, the Colpitts Oscillator consists of a parallel LC resonator tank circuit whose feedback is achieved by way of a capacitive divider. The Colpitts oscillator exists in several forms like most oscillator circuits, and the most common form is the transistor circuit. The tank sub-center circuit's tap is made at the junction of a "capacitive voltage divider" network, which feeds a fraction of the output signal back to the transistor's emitter. The 180o phase shift produced by the two capacitors in series is inverted by another 180o to produce the requisite positive feedback. The resonance frequency of the tank circuit determines the oscillation frequency, which is a purer sine-wave voltage. Ⅸ Frequently Asked Questions about Colpitts Oscillator1.What is the use of Colpitts oscillator?It is used for generation of sinusoidal output signals with very high frequencies. The Colpitts oscillator using SAW device can be used as the different type of sensors such as temperature sensor. As the device used in this circuit is highly sensitive to perturbations, it senses directly from its surface. 2.What is the basic principle of oscillator?There are many types of electronic oscillators, but they all operate according to the same basic principle: an oscillator always employs a sensitive amplifier whose output is fed back to the input in phase. Thus, the signal regenerates and sustains itself. This is known as positive feedback. 3.What is meant by Colpitts oscillator?A Colpitts oscillator, invented in 1918 by American engineer Edwin H. Colpitts, is one of a number of designs for LC oscillators, electronic oscillators that use a combination of inductors (L) and capacitors (C) to produce an oscillation at a certain frequency.