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Overview of switchesMain parameter of switchesSwitch SymbolSwitch DiagramWhat is a toggle switch?How does toggle switches work?Video related to toggle switchesFive ways toggle switch wiringCircuit diagram of toggle switchTypes of Toggle SwitchDPDT Toggle SwitchDPST Toggle SwitchSPDT Toggle SwitchSPST Toggle SwitchLED Toggle SwitchAdvantages and Disadvantages of toggle switchesRocker Switches vs Toggle SwitchesToggle Switch ApplicationsToggle Switch FAQ  Overview of switchesA switch is a piece of equipment used to stop current flow in a circuit. Simply put, a switch has the power to complete or disrupt an electrical circuit. To turn a device ON and OFF, every electrical and electronic application makes use of at least one switch.Switches are therefore a component of the control system, and control action is impossible without them. A switch has two possible states: completely ON (by shutting its contacts) and completely OFF (by opening its contacts).A switch establishes a closed conduit for the current to flow when its contacts are closed, which causes the load to draw power from the source. As demonstrated in the figure below, no power is used by the load when a switch's contacts are open. Main parameter of switchesSwitches ParametersVoltage ratingThe insulation materials, contact separation, rate of separation, and general safety considerations are some of the variables that affect voltage rating.Current carrying ratingThe electronics switches' current specifications are crucial since they will only be able to transport a particular amount of current through their contacts.Current switching ratingAn electromechanical switch's current switching rating is typically lower than its current carrying rating. The problem is that forming and breaking contacts creates arcing, and the contacts can only handle so much of it before the wear on the contacts significantly limits the operational life.Switch formatFor every electronics circuit design, choosing the appropriate switch format is essential. Toggle switches, slider switches, rotary switches, DIPs, thumbwheels, and many more are among the many various switch formats. Any switch's selection process includes the format.Number of operationsThere is always a tiny degree of wear as the contacts of a switch move across one another to ensure the best resistance is obtained.Contact resistanceThere is a higher contact resistance than there would be if the conductor were continuous because a switch's contacts are not a continuous conductor but can be broken and rebuilt.Power ratingThe maximum power that the switch can manage while working is indicated by its power rating. Overriding this rating may result in an excessive buildup of heat inside the device, which could lead to the switch failing and create a safety issue.Inductive ratingIf not handled properly, any inductance in a circuit will raise the intensity of arcing at the contacts and shorten the life of the switch. This means that once current is flowing, it is challenging to stop since the inductance will produce significant back EMFs when the current is stopped. This is because any inductance in the circuit will oppose the change taking place.Contact typeThere are two different types of contacts used in change-over type electromechanical: Break before make and Make before break.  Switch SymbolSwitch Symbol Switch DiagramSwitch Diagram What is a toggle switch?Toggle switches are electrical switches that be opened or closed using a lever or handle that is moved forward and backward. Toggle power switches and joystick switches are other names for these switches. These switches can be used in any electrical application because they are flexible devices.Since switches are typically manipulated manually, the toggle switch, which functions as a straightforward ON/OFF switch in many electrical circuits, is essential. The toggle switch controls the flow of current from the power source to a device or within a device by use of a lever.Toggle Switch How does toggle switches work?The armature switches the contact into position to start or halt an electrical flow when the switch operator pulls the toggle (the actuator). To put it simply, pushing the toggle can turn a gadget on or off. There are two functions that can be used; a momentary function means that the switch is only engaged when the force is applied. An internal spring mechanism forces the armature to return to its initial position in order to accomplish this. A latching toggle switch, in contrast, keeps the state after being depressed until the toggle is depressed once again to release the switch.The basic toggle switch design is as follows, although being available in various forms and configurations. When the toggle is pulled, an armature (a component conducting electrical current) attached to it moves, adding or removing an electrical contact from a circuit and activating or deactivating the circuit.Even though momentary switches also have an associated spring that will draw the actuator back to its starting point if released, the switch will typically stay in place unless manually pushed again. Video related to toggle switchesVideo Description: Add a switch easily to any household electronics item or automotive project easily by watching this short video. Five ways toggle switch wiringStep One: Look at the instruction about the toggle switchesElectrical setups for the many types of equipment that you might wish to install toggle switches on vary substantially. As a result, no single guide is likely to offer a universally applicable solution. The procedures in this section are intended to serve as general guidance for a straightforward on-off (also known as SPST) toggle switch. They should never take precedence over any installation instructions that came with your toggle switch or the appliance you're placing it into.You can look at the below instruction about the toggle switches:Toggle Switches Instruction Step Two: Your device's supply wire should be cutYou must link your toggle switch to the device's power source in order for it to act as an on-off switch. Cut the supply wire for your device with wire cutters at a spot that will make it easiest to route one or both ends of the cable to the switch. Using a wire stripper, remove about 12 inch (1.3 cm) of insulation from each end of the wire.Cut the supply wire Step Three: If the cable does not reach the switch from either end, add a pigtail.A pigtail is a brief wire piece with both ends stripped, often measuring under 6 inches (15 cm). It can be used as a form of "extender" by being attached to cables that aren't quite long enough to reach your toggle switch.Pigtail connetced to switches Step Four: Connect the supply wire to the toggle switchNow that the device's supply wire has been severed, you must insert your toggle switch so that it can control the circuit's current flow in the middle of the break. The kind of toggle switch you have will determine how you should proceed. Step Five: Test your switchWhen your toggle switch is properly wired, carefully reattach the power to the device and check the toggle switch's operation. You can swap out the panel or housing if everything functions as it should. Congratulations! A toggle switch has been fitted successfully. Circuit diagram of toggle switchThe SPDT toggle switch's circuit schematic is displayed below. A 6V battery, two resistors R1 & R3, two LEDs D1 & D3, and a 21236N switch can be used to construct this circuit.Three terminals, including one input and two outputs, make up this switch. Thus, we can acquire two outputs, the first of which comes from pins 2 (COM) and 1 and the second of which comes from pins COM and 3. In three-way circuits, this switch is mostly used to control electrical appliances from two places.The pins 1 and 3 are connected to D1 (an LED) and D2 (an LED), respectively, in the circuit shown above. When pin 1 is toggled, the D1 LED turns on and the D2 LED turns off. In a same manner, when pin 3 is toggled, D2 LED will turn ON and D1 LED will turn OFF. Consequently, we are able to manage two loads using a single SPDT toggle switch.Toggle Switch Circuit Diagram Types of Toggle SwitchThere are four main versions of these switch designs, each of which has a different combination of throws and poles, such as SPDT, SPST, DPDT, and DPST. Poles of these switches are often the distinct power supply controlled by each switch, whereas throws are the various areas the switch can be used, such as ON & OFF.DPDT Toggle SwitchDPST Toggle SwitchSPDT Toggle SwitchSPST Toggle SwitchLED Toggle Switch DPDT Toggle SwitchDouble pole, double throw (DPDT) toggle switches are used to establish or terminate connections between two conductors and two different circuits. There are six terminals on these switches, and terminals 3 and 4 get the necessary power to drive the loads on the other terminals, which are 1, 5, 2, and 6. Four-way or four-position switches are the names given to these switches.DPDT Switches The six terminals of a DPDT toggle switch are. The toggle switch is represented by terminals 3 and 4. The electricity required to drive the loads on terminals 1 and 5, as well as 2 and 6, is supplied to these terminals. Between terminals 1 and 5, terminal 3 can switch. Therefore, terminal 3, which represents the toggle switch, can switch between operating the fan and operating the motor if a fan is connected to terminal 1 and a motor is connected to terminal 5. The same is true for terminal 4, too. Between terminals 2 and 6, terminal 4 can switch. In this case, terminal 4, which acts as the toggle switch, can switch between the heater and the blower if a heater is connected to terminal 2 and a blower is connected to terminal 6.Two input switches on a DPDT switch can each be connected to one of two terminals. It can therefore use two switches to control four distinct circuits or devices.The circuit for a DPDT toggle switch is illustrated below:DPDT Toggle Switch Circuit Diagram  DPST Toggle SwitchThe name "DPST" refers to a double-pile single throw switch, which is used to establish or terminate the connection between two circuit conductors inside a single branch circuit. These switches typically have four terminals that can be used to simultaneously connect and disconnect two pairs of terminals.DPST Switches A 30A DPST switch is used in this wiring layout to connect a 240V AC load appliance (such as a dryer or water heater). The hot wires for 240V are immediately linked to the two pole, single throw switch and the load point as it is illustrated because there is no need to wire the neutral wire. The dryer is directly linked to the ground wire. When turned OFF, the DPST switch will cut both hot wires. Similar to that, while in the ON position, it will join both Hot wires.DPST Toggle Switch Circuit Diagram SPDT Toggle SwitchA single conductor connection with any of two additional single conductors can be made or broken using a toggle switch known as an SPDT, or single pole, double throw. These switches typically have three terminals, which are typically utilized in pairs. Any load must be connected to the first terminal in order to power a specific gadget. To power the loads on Terminals 1 and 3, Terminal 2 receives the necessary power, while Terminal 3 is utilized to connect to any load and turn on any device. This switch can therefore power any of two circuits. Three-way switches are another name for these kinds of switches.SPDT Switches Three terminals make up an SPDT toggle switch. Any load can be connected to Terminal 1 in order to power a specific appliance. Furthermore, any load can be connected to terminal 3 to power any device. The power required to power the loads on terminals 1 and 3 is delivered to terminal 2 at this point. A SPDT switch can therefore operate any of two circuits. It can switch between the two circuits so that various gadgets or circuits can be powered with just a flick of the switch. The circuit for an SPDT toggle switch is illustrated below:SPDT Toggle Switch Circuit DiagramWe link our 9-volt DC power source to terminal 2 in this circuit. The toggle switch at terminal 2 allows us to switch between terminals 1 and 3. A fan is attached to Terminal 1. The DC motor does not operate when the switch is flipped to the left (terminal 1). The DC motor turns on when the switch is flipped to the right (terminal 3), but the fan does not. You can see how we can control two distinct circuits or devices with an SPDT switch in this manner. A double throw switch offers two possibilities. SPST Toggle SwitchSPST, which stands for "Single Pole Single Throw," refers to a device with two terminals, such as input and output. These switches function just like an ON/OFF switch. This switch's primary job is to establish or terminate a connection between a single conductor and a single branch circuit. Once this switch is opened, the circuit will be cut off, stopping any current flow through the load. When the switch is closed, current flows through the load in a similar manner.SPST Switches A SPST toggle switch only has 2 terminals, as you can see. The input is on terminal 1. The output will be at the other terminal. Simple ON-OFF switches are what SPST toggle switches do. They interrupt the circuit when open, preventing current from reaching the load. Current can move across a closed circuit and drive the load. You can see that the DC motor may be started or stopped using this circuit simply as an ON/OFF switch. The circuit for an SPST toggle switch is illustrated below:SPST Toggle Switch Circuit Diagram LED Toggle SwitchToggle switches with illumination operate at 12 volts DC and light up to show the status of your circuit. Add some flair to your switch and control panels by using these lit toggle switches. Our assortment is completed by toggle switches with LED tips, duck bills, and longer handles. Red, blue, green, and amber are the available illumination colors. Toggle switches with illumination are available in an ON-OFF, single pole, single throw design. The switches' connections, which consist primarily of power in, power out, and a ground for the indicator light, are 1/4 inch push-on terminals. The fundamentals of how to wire an illuminated toggle switch are demonstrated in our video.You shouldn't have any trouble wiring an LED rocker switch if you pay close attention to where your ground, power, and acc pins are placed, follow the diagram below (which uses Oznium's LED Round Rocker Switch with a recommended mounting hole diameter of 3/4 inch) :LED Toggle Switch Circuit Diagram Advantages and Disadvantages of toggle switchesAdvantagesDisadvantagesUse of these switches with circuit boards is optimal.While using these switches, a clicking sound will be heard.These switches often have a small footprint, are incredibly sturdy, and are very easy to seal.When compared to rocker switches, these are bigger and bulkier.These switches are effective in controlling electricity.It requires a toggle lock washer.There are small and regular sizes of these switches available.Only low voltage circuits can use it.A lever can be used to extend and operate them.-These switches are energy efficient since they utilize less -These switches are very strong.- Rocker Switches vs Toggle SwitchesRocker switches and toggle switches are the two primary categories of maintained switches. The advantage of having a rocker switch is that you can typically add images, symbols, or even writing to the switch's face to make it more personalized. It therefore especially helpful in situations where function communication is required. Switches that can be sealed easily are perfect for usage with circuit boards. indicating increased resilience against water and dust. enhancing the switch's suitability for hostile conditions.Which switch is best for your project will ultimately depend on its design and environmental factors. From a design standpoint, some people favor the toggle switch's appearance, while others like the rocker switch's more common appearance. Your choice will be influenced by the circumstances. A toggle switch, for instance, may be preferable if the product is for the marine industry because of its IP rating. Toggle Switch ApplicationsThese switches give drivers of cars easy access to headlights, comparable controls, and indicator lights.Conveyor belts, residual current devices, and other industrial and electrical equipment employ these (RCDs).These switches are present in home, commercial, and industrial power outlets.It can serve as the primary switch for industrial machinery like conveyors and packaging machines as well as AC equipment.These switches are employed in switching headlights, logic-level programs, automobiles, and aviation control panels, among other things.Toggle switches are utilized as switching circuits in communications, commercial, and industrial equipment.  Toggle Switch FAQOverview and Applications of toggle switchAn electronic on/off switch is a toggle switch. The best purpose for toggle switches is to change the status of system settings and functionalities. To allow users to select between two opposed states, toggles may be used in place of two radio buttons or a single checkbox. What are the 4 types of switches?Single pole single throw, single pole double throw, double pole single throw, and double pole double throw are the four primary categories of switches. The differences between toggle and switchSince they both manage states but not in the same way, we must first distinguish between a toggle button and a toggle switch: Toggle button: Represents an action that changes a state. Two (or more) mutually incompatible states or possibilities that can be switched are represented by a toggle switch. Should a toggle switch be on the positive or negative?Never switch the ground return side; always switch the supply side. You can flip both lines if you're using a twin pole switch, but you must keep the ground line to the chassis intact. More corrosion is likely to occur on the negative terminal. What is a toggle switch?In order to switch an electrical circuit, toggle switches include an operating lever that can be moved up and down or left and right. A "toggle" is a little wooden rod that is used in place of buttons to fasten garments.

Introduction FPGA is a product of further development on the basis of programmable devices such as PAL, GAL, and CPLD. It appears as a semi-custom circuit in the field of application specific integrated circuits (ASIC), which not only solves the shortcomings of the custom circuit, but also overcomes the limited number of gate circuits of the original programmable device. FPGA is often used in communication, network and other fields to process a large number of network data packets. It is also widely used in aerospace, military defense and other fields. As a hardware test platform before other chips are taped out, it plays an important role in cloud computing, artificial intelligence (AI) and other fields. FPGA Applications, Features and Selection Catalog Introduction Ⅰ FPGA Basic Architecture Ⅱ FPGA Basic Features Ⅲ FPGA Applications 3.1 Circuit Design 3.2 Product Design 3.3 System Application Ⅳ Vacuum Cleaner Based on FPGA 4.1 A Short Brief 4.2 The Composition of the Platform 4.3 Main Hardware Design 4.4 Program Design Points Ⅴ FAQ Ⅰ FPGA Basic Architecture FPGA consists of 6 parts, namely programmable input/output (I/O) unit, basic programmable logic unit, embedded RAM, abundant wiring resources, bottom embedded functional unit and embedded dedicated hard core. Figure 1. FPGA Basic Architecture Each unit is described as follows:🔺Programmable I/O UnitAt present, most FPGA I/O units are designed in programmable mode, that is, through the flexible configuration of software, they can adapt to different electrical standards and I/O physical characteristics; the matching impedance characteristics, the pull-up and pull-down resistors can be adjusted; the output drive current can be adjusted, etc.🔺Basic Programmable Logic UnitThe basic programmable logic unit of FPGA is composed of a look-up table (LUT) and a register. The look-up table completes the pure combinational logic function. FPGA internal registers can be configured as flip-flops with synchronous/asynchronous reset and set, clock enabled, or as latches. FPGA generally relies on registers to complete synchronous sequential logic design. Generally speaking, the configuration of a classic basic programmable unit is a register plus a LUT. However, the internal structures of registers and look-up tables of different manufacturers are different, so the combination modes are also different.An important aspect of learning the LUT and Register ratios of the underlying hive is device selection and sizing. In addition to the basic programmable logic units inside the FPGA, there are embedded RAM, PLL or DLL, dedicated Hard IP Core, etc. These modules can also be equivalent to a certain scale of system gates, so the simple and scientific method is use the number of Registers or LUTs of the device to measure.🔺Embedded RAMNow most FPGAs have embedded RAM, which can be configured as single-port RAM, dual-port RAM, pseudo-dual-port RAM, CAM, FIFO and other storage structures.CAM is the content address memory. The data written to the CAM is compared with every data stored in it and returns the addresses of all internal data that are the same as the port data. Simply put, RAM is a storage unit for writing addresses and reading data, while CAM is just the opposite of RAM. In addition to block RAM, Xilinx and Lattice FPGAs can flexibly configure LUTs into storage structures such as RAM, ROM, and FIFO.🔺Rich Wiring ResourcesThe routing resources connect all the units in the FPGA, and the length and process of the connection determine the driving ability and transmission speed of the signal on the connection. Here the division of wiring resources:1) Full dedicated routing resources: Complete the routing of the global clock and global reset/set within the device.2) Long-term resources: Used to complete the wiring of some high-speed signals and some second global clock signals between device banks.3) Short-circuit resources: Used to complete the logic interconnection and wiring between basic logic units.4) Others: There are various wiring resources and control signal lines such as dedicated clock and reset in the logic unit.In the design process, the place and router often automatically selects the available routing resources to connect the underlying unit modules used according to the topology and constraints of the input logic netlist, so routing resources are often ignored. In fact, the optimization of routing resources is directly related to the use and implementation results.🔺The bottom layer is embedded with functional units, and the resources embedded by different manufacturers will be different.🔺Embedded dedicated hard coreDifferent from the "low-level embedded unit", the hard cores here are mainly those with relatively weak generality, and not all FPGA devices contain hard cores.   Ⅱ FPGA Basic Features 1) Using FPGA to design ASIC circuit (application-specific integrated circuit), users can get suitable chips without film production.2) FPGA can be used as a mid-scale sample for other full-custom or semi-custom ASIC circuits.3) There are abundant triggers and I/O pins inside the FPGA.4) FPGA is one of the devices with the shortest design cycle, the lowest development cost and the lowest risk in the ASIC circuit.5) FPGA adopts high-speed CMOS technology with low power consumption and is compatible with CMOS and TTL levels. Figure  2. FPGA Chip Ⅲ FPGA Applications 3.1 Circuit Design Connection logic and control logic are the areas where FPGA played a relatively important role in the early days and are also the cornerstone of FPGA applications. In fact, it is still quite difficult to apply FPGA in circuit design, which requires developers to have corresponding hardware knowledge (circuit knowledge) and software application capabilities (development tools). So talents in this area are always in short supply, and they are often engaged in new technologies. The successful product development of new products will become the mainstream basic products in the market for designers to apply. In the near future, the design of general-purpose and special-purpose IP will become popular. 3.2 Product Design Apply relatively mature technology to some specific fields such as communication, video, information processing, etc. to develop products that meet the needs of the industry and can be accepted by industry customers. This aspect is mainly a combination of FPGA and professional technology. In addition, there are product design for interface issues with professional customers also includes professional tool products and civilian products. The former focuses on performance, while the latter focuses on price-sensitive product design to achieve product functions as the main purpose.FPGA is a means of realization. In this field, it has the characteristics of interface, control, functional IP, embedded CPU, etc. to realize a system product design with simple structure, high degree of curing, and comprehensive functions for FPGA market. 3.3 System Application The system-level application is the combination of FPGA and traditional computer technology to realize an FPGA version of the computer system. For example, Xilinx V-4, V-5 series FPGA is used to realize the embedded POWER PC CPU, and then cooperate with various peripheral functions. To achieve a basic environment, running LINUX and other systems on this platform also supports various standard peripherals and functional interfaces, which is very helpful for quickly forming large-scale FPGA systems.In system-level applications, if the developers do not have the ability to expand the system, it is meaningless to just engage in programming. Of course, the development of device drivers is another case. The system-level application seems to have a high starting point, but it does not have deep development ability, it is likely to become a hobbyist, just like many people can make web pages but cannot be called programming.   Ⅳ Vacuum Cleaner Based on FPGA 4.1 A Short Brief Design of indoor intelligent vacuuming platform based on FPGA.Intelligent environmental cleaners have increasingly become the focus of research because they can replace people in environmental cleaning. Although they achieve intelligence, most of them have complex structures and high integration, which are not conducive to developers to expand their functions. On the basis of researching and summarizing the relatively mature products on the market, this paper designs and implements an indoor intelligent vacuuming platform based on a highly programmable FPGA. The platform has self-navigation, can clean most of the space, and is compact in shape, stable in operation and low in noise. More importantly, it has a simple structure and a user-friendly interface, which is convenient for further development of operation and functions. Figure  3. Body Frame 4.2 The Composition of the Platform The overall frame design of the platform proposed in this paper is shown in Figure 3, and a car with four wheels is used as the carrier of the entire platform. The FPGA controller is used as the main controller of the entire platform, and is connected to the photoelectric sensors jk1, jk2, jk3, jk4 and the collision switch jk5 through I/O to realize the detection of platform obstacles. Then output PWM waveform through I/O to drive speakers and high-low, and the change of the level drives the on and off of the LED to form an acousto-optic circuit. Finally the stepper motor dj1, dj2 and the DC dust collection motor dj3 are driven by controlling the signal control line of the motor driver to realize the movement and dust collection of the platform. 4.3 Main Hardware Design The system is mainly composed of FPGA main control chip, photoelectric sensor, collision switch, wireless remote control transmitter module controlled by two STC89C52 microcontrollers, two mode selection chips, acousto-optic circuit, drive motor, vacuum cleaner motor and the power supply circuit of the whole system, such as as shown in the Figure 4. Figure  4. Main Control System 🔺FPGA Chip SelectionAccording to the overall design of the platform, the basic requirements for the chip can be drawn:(1) At least 6 PWM waveform outputs are required.(2) One serial communication interface is required.(3) A real-time chip that requires a higher 12 V to be converted to 3.3 V.(4) Higher processing speed.(5) There are more I/O interfaces.Taking these conditions into consideration, the EP2C35F672C6 model in the CycloneII series FPGA produced by Altera can basically meet the requirements. It has excellent operation speed, low cost and DSP module, large internal memory, multi-channel PWM output, flexible design and comprehensive use of multiple languages, and the cost performance is relatively high.🔺Configuration Circuit Design Points(1) Power supply circuit: The power supply system uses 12V power supply as the input power supply, uses L7805CV to step down it to 5V, and then converts 5V to 3.3V and 1.2V by TPS37HD301. The power supply point of the I/O port of the FPGA is 3.3V, the core supply voltage is 1.2V. Because the motor drive system uses the 5V signal of the controller, and the port voltage of the FPGA is 3.3V, the I/O voltage must be boosted to 5V, and the 74HCT245 boost chip is used here.(2) Clock and reset circuit: ZPB-26-16 M is an active crystal oscillator in the clock circuit, and the frequency is 16MHz, which makes the serial port baud rate more accurate. At the same time, it can support the PPL function and ISP download function inside the chip. The reset circuit takes hardware reset and software reset.(3) Debug JTAG and download circuit: Because the soft core ISP and JTAG can be built directly inside the FPGA, the hardware circuit is connected to a JTAG interface of IDC-10.(4) Configuration storage circuit: EPCS16 is selected as the ROM of the FPGA, which can be repeatedly programmed by the download cable or other equipment, and can also be programmed online through the AS interface. Use the 4MHz On-Chip memory inside the FPGA chip as the RAM of the FPGA.(5) Sensor and collision switch: E3F-DS5C4.P1R photoelectric switch, used to detect obstacles and stairs, which is a cylindrical diffusion type with a maximum distance of 5cm, or an adjustable NPN type normally open photoelectric switch. The collision switch mainly cooperates with the front sensor to protect the front of the platform. When the platform hits the obstacle ahead, trigger the switch to make the platform avoid the obstacle.(6) Wireless sending and receiving module: XL02-232AP1 wireless module is a half-duplex wireless transmission module with UART interface, which can work in the 433MHz public frequency band and meet the wireless regulatory requirements.(7) Drive and vacuum motor: The platform adopts the front wheel dual drive, the motor selects the two-phase hybrid stepping type, and the vacuum cleaner motor adopts the DC motor. The main electrical parameters of the stepping motor are: ① Step angle: 1.8°② Phase current: 0.87 A③ Holding torque: 0.24 nm④ Phase resistance: 3.3 Ω⑤ Phase inductance: 5.0 mH⑥ Weight: 0.2 kg(8) Sound and light circuit and automatic cleaning time input display circuit: The sound and light circuit is mainly composed of light-emitting diodes and buzzers, which are directly connected to the FPGA to remind the working state of the platform. Use 4 buttons (OK, Initial, Up, Down) to input the cleaning time, and then three digital tubes display the set time. The cleaning time is counted by the timer inside the FPGA. When the timer is completed, the platform stops working. 4.4 Program Design Points Divide the program into two parts: hardware programming and software programming. For hardware programming, timing simulation of hardware circuits is required to determine the effect of debugging.🔺Hardware Programming and SimulationThe platform mainly generates input signals through sensors and collision switches, and processes the signals through FPGA. Finally, the FPGA transmits the processed signals to the motor, and the motor completes a series of actions, as shown in Table 1. So its logic design is the key to realize intelligence. After the hardware selection is completed, use Quartus II to build the hardware schematic diagram. After compiling, perform timing simulation on jk1, jk2, jk3, and jk4, analyze the timing relationship, estimate the performance of the design, and check and eliminate competition risks.Table 1: Relationship between Motor Status and Platform Working Status. dj1 dj2 dj3 Cleaner Status Turn Forward Turn Forward ON Vacuuming Forward Turn Back Turn Forward ON Vacuuming Left Turn Forward Turn Back ON Vacuuming Right Turn Back Turn Back ON Vacuuming Back The realization of platform work in automatic cleaning mode depends on the cooperative work of sensors (jk1, jk2, jk3, jk4) and motors (dj1, dj2, dj3), and the logical relationship is designed according to their functions.Table 2: Relationship between Sensor Status and Platform Working Status. jk1 jk2 jk3 jk4 Cleaner Status 1 1 1 1 Vacuuming Forward 1 1 0 1 Vacuuming Left 1 0 1 1 Vacuuming Right 1 0 0 1 Vacuuming Forward 0 1 0 1 Vacuuming Forward (Turn 90° Left)  0 0 1 1 Vacuuming Forward (Turn 90° Right)  0 0 0 1 Vacuuming Back When the hardware selection is completed, use Quartus II to build the hardware schematic diagram. After compiling, perform timing simulation on jk1, jk2, jk3, and jk4 to analyze the timing relationship.🔺Software ProgrammingAfter the hardware design and debugging is completed, the software system design is also carried out. Write a C program in a C language file to program the SoPC. The overall algorithm flow of the platform work is shown in Figure 5. When the platform is powered on, firstly enter the automatic cleaning and manual remote cleaning mode. After the automatic cleaning mode is selected, input the working time of the platform's automatic cleaning through the keyboard, and use the sensor to judge whether it encounters obstacles or stairs during the cleaning process. Through the interrupt, check whether the set time is reached at all times. If not, the program will return to running. However, if the set time is up, the program will end and the platform will stop working. When remote cleaning is selected, platform movement is controlled by the operator. Figure 5. Algorithm Flowchart Through hardware selection, construction and debugging, and software language writing and debugging, a simple platform has been successfully made, and various predetermined functions have been realized. Compared with similar products on the market, its structure is simpler, the cost is lower, the flexibility and scalability are stronger, and it provides a hardware-supported platform for researchers to develop more functions, which has practical value. As microprocessors continue to advance and sensing technology evolves, their performance can continue to improve and costs can continue to decline. However, in the process of simulation and implementation, it is found that its specific process algorithm is not rigorous enough, and it is necessary to continue to improve it in the future.   Ⅴ FAQ 1. What is FPGA architecture?The field-programmable gate array (FPGA) is an integrated circuit that consists of internal hardware blocks with user-programmable interconnects to customize operation for a specific application. 2. What are the parts of an FPGA?Structure of an FPGAConfigurable Logic Block (CLB)Digital Signal Processing (DSP) Slice.Transceivers.Block Random Access Memory (BRAM)Input/Output (IO) Blocks. 3. What is a basic unit of an FPGA?The configurable logic blocks (CLBs) are the basic logic unit of an FPGA. Sometimes referred to as slices or logic cells, CLBs are made up of two basic components: flip-flops and lookup tables (LUTs). 4. What is FPGA and its types?FPGA stands for Field Programmable Gate Array which is an IC that can be programmed to perform a customized operation for a specific application. They have thousands of gates. In the field of VLSI FPGAs have been very popular. 5. What is the function of FPGA?FPGAs are mainly used to design application-specific integrated circuits (ASICs). First, you design the architecture of such a circuit. Then, you use an FPGA to build and check its prototype. Errors can be corrected. 6. What is FPGA and its application?The FPGA is Field Programmable Gate Array. It is a type of device that is widely used in electronic circuits. FPGAs are semiconductor devices which contain programmable logic blocks and interconnection circuits. It can be programmed or reprogrammed to the required functionality after manufacturing. 7. What are the advantages of FPGA?FPGA advantagesLong-term availability.Updating and adaptation at the customer.Very short time-to-market.Fast and efficient systems.Acceleration of software.Real-time applications.Massively parallel data processing. 8. What is inside CLB in FPGA?A configurable logic block (CLB) is the basic repeating logic resource on an FPGA. When linked together by routing resources, the components in CLBs execute complex logic functions, implement memory functions, and synchronize code on the FPGA. 9. What are the main applications of FPGAs?Main FPGA applications are: Medical, video & image processing, telecom & datacom, server & cloud and defense and space. FPGA chips are used in both wired and wireless communications. 10. What are the industrial applications of FPGA boards?Such applications include multiple sensor dome cameras, HD (High Definition) cameras, night-vision cameras, etc. FPGAs provide the differentiation factor and the processing power to implement such complex solutions. 11. What are the applications of CPLDs and FPGAs?Applications of CPLDCPLDs can be used as bootloaders for FPGAs and other programmable systems. CPLDs are often used as address decoders and custom state machines in digital systems. Due to their small size and low power consumption, CPLDs are ideal for use in portable and handheld digital devices. 12. What programmable technology is used in a FPGA devices?FPGA emerged from relatively simpler technologies such as programmable read-only memory (PROM) and programmable logic devices (PLDs) like PAL, PLA, or Complex PLD (CPLD). It consists of three main parts: Configurable Logic Blocks — which implement logic functions. Programmable Interconnects — which implement routing. 13. What are the features of FPGA?The basic features of FPGA are: 1) FPGA design ASIC circuit, the user does not need to chip production, you can get a combination of chips. - 2) FPGA can do all other custom or semi-custom ASIC circuit of the sample sample. 3) FPGA has a rich internal trigger and I / O pin. 14. Is a FPGA a computer?An FPGA is a chip consisting of a series of logic blocks which can be modified and configured by the user. ... FPGA are programmable chips and their functionality can be updated multiple times. FPGAs come in array of size and prices and are most likely used in low-mid size volume products.

Introduction Capacitors are the most common passive components used in circuit design. Its function is to block the AC current while pass the DC current, and it also has the function of power storage, and has a good filtering effect, which can output the pulsating signal in a smooth way. The application of capacitors in electronics is very common. Let's talk about the common types of capacitor in circuits and their uses. Basic Introduction to Capacitors Catalog Introduction Ⅰ Types of Capacitors in Use with Models 1.1 Ceramic Capacitors (CC) 1.2 Polyester Capacitor (CL) 1.3 Polystyrene Capacitors (CB) 1.4 Polypropylene Capacitors (CBB) 1.5 Monolithic Ceramic Capacitor (MLCC) 1.6 Mica Capacitors 1.7 Paper Capacitors (CZ) 1.8 Metallized Paper Capacitors (CJ) 1.9 Aluminum Electrolytic Capacitors (CD) 1.10 Tantalum Electrolytic Capacitors (CA) 1.11 Mica Trimmer Capacitors (CY) 1.12 Ceramic Trimmer Capacitors (CC) 1.13 Film Trimmer Capacitors 1.14 Air Variable Capacitor (CB) 1.15 Film Variable Capacitors Ⅱ FAQ Ⅰ Types of Capacitors in Use with Models Virtually all types of capacitor are available as following: 1.1 Ceramic Capacitors (CC) 🔺Material: Use ceramic material as medium, coat a layer of metal (silver) film on its surface, and then sinter at high temperature as an electrode. Ceramic capacitors are divided into Class 1 dielectrics (NPO, CCG); Class 2 dielectrics (X7R, 2X1) and Class 3 dielectrics (Y5V, 2F4).🔺Types: Ceramic capacitors are divided into two types: high-frequency ceramics and low-frequency ceramics. Capacitors with a small positive temperature coefficient of capacitance are used in highly stable oscillation circuits as loop capacitors and pad capacitors. Low-frequency ceramic capacitors are limited to bypassing or blocking DC in circuits with lower operating frequencies, or occasions (including high frequencies) that do not require high stability and loss. Such capacitors should not be used in pulsed circuits because they are prone to breakdown by pulsed voltages.🔺Features: Class 1 have the advantages of small temperature coefficient, high stability, low loss and high withstand voltage. The maximum capacity does not exceed 1000pF, commonly used are CC1, CC2, CC18A, CC11, CCG and other series. Mainly used in high frequency circuits.Class 2 and Class 3 are characterized by high dielectric coefficient, large capacity (up to 0.47μF), small volume, and poor loss and insulation compared to Class 1. 🔺Application Models: Widely used in medium and low frequency circuits for DC blocking, coupling, bypassing and filtering capacitors, and commonly used are CT1, CT2, CT3 and other three series. 1.2 Polyester Capacitor (CL) 🔺Material: A non-polar capacitor with a positive temperature coefficient (that is, when the temperature increases, the capacitance becomes larger) made of polar polyester film as the medium.🔺Advantages: High temperature resistance, high pressure resistance, moisture resistance and cheap price, suitable for bypass capacitors.🔺Application Models: Generally used in medium and low frequency circuits, and commonly used models are CL11, CL21 and other series.🔺Value Identification: Internationally, the withstand voltage value of capacitors is usually represented by letters. The common correspondence between codes and bases is:A: 1.0; B: 1.25; C: 1.6; D: 2.0; E: 2.5; F: 3.15; G4.0;H: 5.0; J: 6.3; K: 8.0; Z: 9.0;The number in front of the letter represents the power of 10, for example, 2A is 102*1.0=100V, 2C is 102*1.6=160V and so on.The letters behind the withstand voltage value represent the capacitance in pF.For example, 823 means the capacity is 82*10^3=82000Pf, 224 means 22*104=220000pf=0.22μF. The last letter means the precision, such as J means the capacity tolerance is ±5% and so on.Typical capacitor identification example: 2A823J is 82000Pf±5%, withstanding voltage 100V. 1.3 Polystyrene Capacitors (CB) 🔺Material: There are two types of foil type and metallized type.🔺Advantages: Foil type has large insulation resistance, low dielectric loss, stable capacity and high precision, but large volume and poor heat resistance; metallized type has good moisture resistance and stability, and can recover after breakdown, also it has advantages of the low insulation resistance and poor high frequency characteristics.🔺Application Models: Generally used in medium and high frequency circuits, and commonly used models are CB10, CB11 (non-sealed foil type), CB14~16 (precision type), CB24, CB25 (non-sealed metallization), CB80 (high pressure type), CB40 (sealed metallization) and other series. In short, they used in various precision measuring instruments, car radios, industrial proximity switches and high-precision digital-to-analog converter circuits. 1.4 Polypropylene Capacitors (CBB) 🔺Material: It is a negative temperature coefficient non-polar capacitor that made of non-polar polypropylene film as the medium. There are two types of unsealed (commonly encapsulated with colored resin paint) and sealed (encapsulated with metal or plastic housing).🔺Advantages: Small loss, stable performance, good insulation and large capacity.🔺Application Models: Generally used in medium and high frequency circuits or as starting capacitors for motors, and commonly used foil polypropylene capacitors include CBB10, CBB11, CBB60, CBB61, etc.; metallized polypropylene capacitors include CBB20, CBB21, and CBB401 series.CBB capacitor series are used in high frequency and high power circuits such as filtering, cross-line, resonance, etc. 1.5 Monolithic Ceramic Capacitor (MLCC) 🔺Material: Multi-layer laminated ultra-miniature capacitors sintered with barium titanate-based ceramic materials.🔺Advantages: It has the advantages of reliable performance, high temperature resistance, moisture resistance, large capacity (range 1pF~1μF), and small leakage current.🔺Disadvantages: Low working voltage (withstand voltage lower than 100V).🔺Application Models: Widely used in resonance, bypass, coupling, filtering, etc, and commonly used are CT4 (low frequency), CT42 (low frequency), CC4 (high frequency), CC42 (high frequency) and other series.🔺ClassificationClass 1It is a temperature-compensated NPO dielectric. The electrical performance of this capacitor is the most stable and basically does not change with temperature, voltage and time. In short, it is an ultra-stable, low-loss capacitor material type and is suitable for high stability and reliability requirements. frequency, UHF and VHF circuits.Class 2It is a high dielectric constant X7R series, so it can make capacitors with larger capacity than NPO dielectrics. This kind of capacitor has relatively stable performance. With the change of temperature, voltage and time, its unique performance does not change significantly. It is a type of stable capacitor material. It is used in DC blocking, coupling, bypass, filter circuit and frequency circuit with high reliability requirements.Class 3It uses Y5V dielectric. This capacitor has a high dielectric constant and is often used in the production of large-capacity capacitors with larger specific capacitance and higher nominal capacity. However, its capacity stability is worse than that of X7R, and its capacity and loss are more sensitive to test conditions such as temperature and voltage. It is mainly used in oscillation, coupling, filtering and bypass circuits in electronic complete machines.Monolithic ceramic capacitors are larger than ordinary ceramic capacitors (10pF~10μF), and have the advantages of large capacitance, small size, high reliability, stable capacitance, high temperature resistance, good insulation, and low cost, so they are widely used. They can not only replace mica capacitors and paper capacitors, but also replace some tantalum capacitors, and are widely used in small and ultra-small electronic devices (such as liquid crystal watches and micro instruments). 1.6 Mica Capacitors 🔺Material: Mica is used as the medium, and a layer of metal film (silver) is sprayed on the surface as the electrode, which is laminated according to the required capacity and then dipped and compressed in the bakelite shell (or ceramic or plastic shell).🔺Advantages: Good stability, small distributed inductance, high precision, low loss, large insulation resistance, good temperature characteristics, that is, good frequency characteristics, high operating voltage (50V~7kV) and so on.🔺Application: It is generally used for signal coupling, bypassing, tuning, etc. in high-frequency circuits. For example, they are common in occasions that require high stability and reliability of capacitors, such as instruments and meters of electronic, power and communication equipment, and are also used in aerospace, aviation, navigation, rockets, satellites, military electronics, and oil exploration equipment. Commonly used ones are CY, CYZ, CYRX and other series. 1.7 Paper Capacitors (CZ) 🔺Material: The thin capacitor special paper is used as the medium, and the aluminum foil or lead foil is used as the electrode.🔺Advantages: The capacitance (100pF~100μF) has a wide working voltage range, and the maximum withstand voltage value can reach 6.3kV.🔺Disadvantages: Large size, low capacity accuracy, large loss, and poor stability.🔺Classification: Paper capacitors are divided into inductive type and non-inductive type according to winding methods. The inductive core is actually a ribbon coil with many turns, so the inductance is large. The non-inductive type is to stagger the electrode foils to both sides of the paper, so that the sides of the foil strips extend out of the paper strips, and then the leads are welded after winding into a cylindrical core. In this way, the coils of the electrode foil are short-circuited with each other, so the inductance is very small. This capacitor can be used at higher frequencies.🔺Application Models: Common ones are CZ11, CZ30, CZ31, CZ32, CZ40, CZ80 and other series. 1.8 Metallized Paper Capacitors (CJ) 🔺Material: Using vacuum evaporation technology, a layer of metal film is evaporated on the paper coated with paint film as an electrode.🔺Advantages: Compared with ordinary paper capacitors, it is small in size, large in capacity, and has strong recovery ability after breakdown, which is an unique characteristic. For common situation, when the paper-dielectric capacitor is broken down, the paper medium is scorched, and the two layers of metal foil are melted together at the breakdown place to form a short circuit. But for metallized paper capacitors, the metal film at the breakdown place evaporates at high temperature, leaving only insulating holes and no short circuit.🔺Application Models: Common ones are CJ10, CJ11 and other series. 1.9 Aluminum Electrolytic Capacitors (CD) 🔺Material: The polar one is made by winding the aluminum foil (positive electrode) with an oxide film and the backing paper impregnated with the electrolyte solution together with the cathode foil lamination. Appearance package has tube type and vertical type. And there is a blue or black plastic cover outside the aluminum shell.🔺Advantages: The capacity range is large, generally 1~10000μF, and the rated working voltage range is 6.3V~450V.Disadvantages: Medium loss, large capacity error (maximum allowable deviation is +100%, -20%), poor high temperature resistance, long storage time and unstable working state.🔺Application: Usually used in DC power circuits or medium and low frequency circuits for filtering, decoupling, signal coupling, time constant setting, and DC blocking. Note that the polarity cannot be reversed when used as a filter capacitor in a DC power supply.Selection: The capacity and withstand voltage marked on the body of the aluminum electrolytic capacitor are very important and are the most basic content for selecting capacitors. In the actual selection of capacitors, a capacitor with a larger capacity should be used for places where the current changes rapidly, but it’s not always good. First, the larger the capacity, the higher the cost and volume. In addition, the larger the capacitor, the higher the charging current. The bigger it is, the longer the charging time will be. These are all to be considered in practical application selection. 1.10 Tantalum Electrolytic Capacitors (CA) 🔺Material: There are two forms:1) The foil type tantalum electrolytic capacitor adopts a winding core inside, the negative electrode is liquid electrolyte, and the medium is oxidized tantalum. Common models are CA30, CA31, CA35, CAk35 series.2) The tantalum powder sintered positive electrode is sintered with very fine tantalum powder blocks. Packaging comes in many forms. Widely used models include CA41, CA42, CA42H, CA49, CA70 (non-polar) and other series.🔺Advantages:1) Small SizeSince capacitors use tantalum powder with very fine particles, and the dielectric constant ε of the tantalum oxide film is 17 higher than that of the aluminum oxide film, the capacitance per unit volume of the tantalum capacitor is large.2) Wide Operating Temperature RangeGenerally, tantalum electrolytic capacitors can work normally under the temperature of -50℃~100℃. Although aluminum electrolytic capacitors can also work in this range, their electrical performance is far inferior to that of them.3) Long Life, High Insulation Resistance and Small Leakage CurrentThe tantalum oxide film dielectric in tantalum electrolytic capacitors is not only resistant to corrosion, but also maintains good performance for a long time.4) Good Impedance Frequency CharacteristicsFor capacitors with poor frequency characteristics, when the operating frequency is high, the capacitance drops significantly, and the loss (tgδ) also rises sharply. But solid electrolytic capacitors can work above 50kHz. As the frequency increases, the capacity of capacitors also decreases, but the decrease is small. Some data show that the capacity decreases by less than 20% when working at 10kHz, while the capacity of aluminum electrolytic capacitors decreases by 40%.5) High ReliabilityThe chemical properties of the tantalum oxide film are stable, and because the tantalum anode substrate Ta2O5 is resistant to strong acids and alkalis, it can use solid or acid-containing liquid electrolytes with low resistivity, which makes the loss of tantalum electrolysis smaller than that of aluminum electrolytic capacitors, and the temperature stability is good.🔺Disadvantages: High production cost and low pressure resistance.🔺Application: Widely used in various medium and low frequency circuits and time constant setting circuits in communications, aerospace, military and household appliances.With the properties of storing electricity, charging and discharging, etc, they are mainly used in filtering, energy storage and conversion, mark bypass, coupling and decoupling, and time constant components. Pay attention to its performance characteristics in application, and correct use will help to give full play to its functions, such as considering the working environment of the product and its heating temperature, and taking measures such as derating, if it is used improperly, it will affect the service life of the product.   A variable capacitor is a capacitor whose capacitance can be adjusted within a certain range. When the relative effective area between the pole pieces or the distance between the pieces changes, its capacitance changes accordingly. Usually used as a tuning capacitor in a radio receiving circuit. Here are several types as following: 1.11 Mica Trimmer Capacitors (CY) 🔺Material: It consists of a fixed piece and a moving piece. The fixed piece is a metal piece, and a layer of mica flakes is the most medium on its surface. The moving piece is an elastic copper or aluminum piece. Adjust the moving piece and the fixed piece by adjusting the screws on the moving piece, then the distance between the slices changes the capacitance. There are single trimmers and double trimmers.🔺Advantages: The capacitance can be adjusted repeatedly.🔺Application: Used in transistor radios, electronic instruments, and electronic equipment. 1.12 Ceramic Trimmer Capacitors (CC) 🔺Material: Ceramic is used as the medium, and the semicircular silver layer is plated on both the moving plate and the stator. By rotating the moving plate to change the relative position between the two silver plates, the size of the capacitance can be changed.🔺Advantages: Small size, can be adjusted repeatedly, easy to use.🔺Application: Used in transistor radios, electronic instruments, and electronic equipment. 1.13 Film Trimmer Capacitors 🔺Material: Use organic plastic film as a medium, that is, add it between the moving piece and the fixed piece. Adjust the screw on the moving piece, and make the moving piece rotate to change the capacity. Film trimmer capacitors are generally divided into double trimmers and quadruple trimmers. Some sealed double-connected or four-connected variable capacitors have their own thin-film trimmer capacitors, which are installed on the top of the casing, making it easier to use and adjust.🔺Advantages: With small size, light weight, it can be adjusted repeatedly and is easy to use.🔺Application: Used in transistor radios, electronic instruments, and electronic equipment. 1.14 Air Variable Capacitor (CB) 🔺Material: The electrode consists of two sets of metal sheets. One set is the fixed piece, the other is the moving piece, and the air is used as the medium between them. When the rotor is rotated to make it all screw into the stator, its capacitance is the largest, on the contrary, when the rotor is fully screwed out of the stator, the capacitance is the smallest. Air variable capacitors are divided into single-connection and double-connection.🔺Advantages: It is easy to adjust, with stable performance, and not easy to wear.🔺Disadvantage: Bulky.🔺Application: Used in radios, electronic instruments, high-frequency signal generators, and communication electronic equipment. 1.15 Film Variable Capacitors 🔺Material: A plastic film is added between the moving piece and the stator as a medium, and the shell is encapsulated by transparent or translucent plastic, so it is also called a sealed double-connected and four-connected variable capacitor.🔺Advantages: Small size and light weight.🔺Disadvantages: It is easy to wear.🔺Application: Single connection is mainly used in simple radios or electronic instruments; double connection is used in transistor radios and electronic instruments and electronic equipment; quadruple connection is commonly used in AF/FM multi-band radios.   Ⅱ FAQ 1. What are different types of capacitors?Types of CapacitorsCeramic Capacitors.Film Capacitors.Power Film Capacitors.Electrolytic Capacitors.Ceramic capacitors.Film capacitors.Paper capacitors.Electrolytic capacitors. 2. What are the 2 types of capacitor?Capacitors are divided into two mechanical groups: Fixed capacitors with fixed capacitance values and variable capacitors with variable (trimmer) or adjustable (tunable) capacitance values. The most important group is the fixed capacitors. Many got their names from the dielectric. 3. What is the difference between different types of capacitors?The primary difference between the two is that one uses paper while the other uses plastic. Plastic film capacitors hold an advantage over impregnated-paper types in that they have smaller tolerances, high reliability, a long service life, and can continue operating sufficiently while in high temperatures. 4. What devices use capacitor?Capacitors are essential components in a wide range of electronic systems including smart phones, household electric appliances, electric vehicles, and medical devices to name a few. 5. What are capacitors used for?Capacitor, device for storing electrical energy, consisting of two conductors in close proximity and insulated from each other. 6. What is capacitor and its applications?Capacitor is a basic storage device to store electrical charges and release it as it is required by the circuit. Capacitors are widely used in electronic circuits to perform variety of tasks, such as smoothing, filtering, bypassing etc…. One type of capacitor may not be suitable for all applications. 7. Where are capacitors used and why?Capacitors are widely used in electronic circuits for blocking direct current while allowing alternating current to pass. In analog filter networks, they smooth the output of power supplies. 8. How is capacitor used in real life?The most common use for capacitors is energy storage. Additional uses include power conditioning, signal coupling or decoupling, electronic noise filtering, and remote sensing. Because of its varied applications, capacitors are used in a wide range of industries and have become a vital part of everyday life. 9. What are capacitors used for list 5 applications?Applications of capacitors1) Energy storage.2) Pulsed power and weapons.3) Power conditioning.4) Power factor correction.5) Suppression and coupling. 5.1 Signal coupling. 5.2 Decoupling.6) Motor starters. 6.1 Signal processing. 6.2 Tuned circuits.7) Sensing. 7.1 Changing the dielectric.8) Oscillators. 10. What are the advantages of capacitors?Advantages of capacitors include a very high cycle life and charge rates that nearly match discharge rates. Also, supercapacitors can be “floated” for long lengths of time. This means that they will hold their charge (potential energy) for a long period without a large residual decay. 11. Which capacitor is used for high frequency?Mica capacitors have low resistive and inductive components associated with it. Hence, they have high Q factor and because of high Q factor their characteristics are mostly frequency independent, which allows this capacitor to work at high frequency. 12. Where are capacitors used examples?They are used to store energy and then release it when needed.Case 1: Camera flash. A camera flash requires a lot of energy in a short space of time in order to produce a bright enough flash. ...Case 2: Computer emergency shutdown. If a computer loses power it will not be able to shutdown safely. ...Case 3: AC to DC conversion.

Introduction Everyone has heard of FPGA more or less, such as Bitcoin mining, or Microsoft said before that it will use FPGA instead of CPU in the data center. So what exactly is it? Why use it? Compared with CPU, GPU, and ASIC, what are the characteristics of FPGA? FPGA is a chip that can reconfigure circuits and is a hardware reconfigurable architecture. Through programming, users can change its application scenarios at any time, and it can simulate various parallel operations of hardware such as CPU and GPU. By interconnecting with the high-speed interface of the target hardware, the FPGA can complete the low-efficiency part of the target hardware, thereby achieving acceleration at the system level. What Is an FPGA? Catalog Introduction Ⅰ FPGA vs CPU vs GPU vs ASIC Ⅱ Five Advantages of FPGA 2.1 Performance 2.2 Time-to-Market 2.3 Cost 2.4 Stability 2.5 Long-Term Maintenance Ⅲ New Applications of FPGA Ⅳ Development Trend of FPGA Ⅴ FAQ Ⅰ FPGA vs CPU vs GPU vs ASIC The core difference between FPGA and CPU, GPU, ASIC chips, etc. is that the connection and logic layout of the underlying operation unit are not solidified. Users can program the logic unit and switch array through EDA software to configure the function, so as to realize the integration of specific functions.FPGA appears as a semi-custom circuit in the field of application-specific integrated circuits (ASIC), which not only solves the shortcomings of custom circuits, but also improves the limited number of original programmable device gate circuits. Compared with ASIC chips, an important feature of FPGA is its programmable characteristics, that is, the user can specify the FPGA to realize a specific digital circuit through the program. Furthermore, FPGA chips are one of the best choices for small batch systems to improve system integration and reliability. Figure 1. FPGA Basic Structure So why is FPGA so fast? This is all because the computer's CPU(central processing unit) and GPU(graphics processing unit) belong to the von Neumann structure, with instruction decoding and execution, and shared memory. FPGAs, on the other hand, are instruction-free and memory-free architectures that make FPGA chips much more energy-efficient than CPUs or even GPUs. Figure 2. Von Neumann Structure In the von Neumann architecture, since the execution unit (such as the CPU core) may execute any instruction, so an instruction memory, a decoder, an operator of various instructions, and branch and jump processing logic are required. Due to the complex control logic of the instruction stream, it is impossible to have too many independent instruction streams. Therefore, the GPU uses SIMD (single instruction, multiple data) to allow multiple execution units to process different data at the same pace, and the CPU also supports SIMD instruction. The function of each logic unit of the FPGA has been determined during reprogramming, and no instructions are required. Figure 3. Computer CPU If the GPU is used for acceleration, in order to fully utilize the GPU computing, the batch size cannot be too small, and the delay will be on the order of milliseconds. Using FPGA to accelerate, only microsecond-level PCle delay is required. Why is FPGA so much lower latency than GPU? This is basically an architectural difference. FPGAs have both pipeline parallelism and data parallelism, while GPUs have almost only data parallelism (with limited pipeline depth).For example, FPGA chips can change the running hardware design on the chip every few seconds, while chips such as CPU and ASIC are already solidified when they leave the factory and cannot be changed. If ASIC, CPU, GPU, etc. are built buildings, and the routes of rooms, corridors, and stairs in the building have been fixed, while the interior of FPGA is similar to the magic staircase in Hogwarts, which can change the route of room to room at any time. In addition, FPGA does not need to compile the instruction system at the software application level like CPU and GPU. To program FPGA, use hardware description language, and directly compile and burn it into a combination of transistor circuits, that is, directly use transistor circuits to implement user algorithms.The biggest feature of FPGA is its flexibility. It can realize any digital circuit you want and can customize various circuits. Reduce the shackles of special chips, truly tailor-made for your own products, you can flexibly change the design during the design process, and have field programmability, so it is especially suitable for applications that require continuous changes in physical operation logic, such as AI algorithm optimization, data center applications, etc. Architecture Throughput（int ops） Delay Flexibility CPU ~1T N/A Very High GPU ~10T ~1ms High FPGA(Stratix V) ~1T ~1us High FPGA(Stratix 10) ~10T ~1us High ASIC ~10T ~1us Low The FPGA is set up by the RAM stored on the chip to reset its working state, so the on-chip RAM needs to be programmed when working. Users can use different programming methods according to different configuration modes, which can be said to be very flexible and convenient. The FPGA has the following configuration modes:🔺Parallel Mode: Parallel PROM, Flash configures FPGA.🔺Master-Slave Mode: One PROM configures multiple FPGAs.🔺Serial Mode: Serial PROM configures FPGA.🔺Peripheral Mode: The FPGA is used as a peripheral of the microprocessor and programmed by the microprocessor. Computational performance compared with CPU: For example, Stratix series FPGAs perform integer multiplication operations, and their performance is equivalent to that of a 20-core CPU, and for floating-point multiplication operations, their performance is equivalent to an 8-core CPU.Computational performance compared with GPU: FPGA performs integer multiplication and floating-point multiplication operations. There is an order of magnitude difference in performance compared to GPU. The computing performance of GPU can be approached by configuring multipliers and floating-point operation components. Figure 4. CPU and GPU Architecture Diagram The core advantage of FPGA for performing computation-intensive tasks: tasks such as search engine sorting and image processing have strict requirements on the return time limit of results, and it is necessary to reduce the delay of computing steps. Under the traditional GPU acceleration scheme, the data packet size is large, and the delay can reach the millisecond level. Under the FPGA acceleration scheme, the PCIe latency can be reduced to the microsecond level. Driven by long-term technology, the data transmission delay between CPU and FPGA can be reduced to less than 100 nanoseconds.The FPGA can build the same number of pipelines (pipeline parallel structure) for the number of data packet steps, and the data packets can be output immediately after being processed by multiple pipelines. The GPU data parallel mode relies on different data units to process different data packets, and the data units need to be input and output consistently. For stream computing tasks, the FPGA pipeline parallel structure has a natural advantage in latency. FPGA is used to process communication-intensive tasks and is not limited by network cards. It outperforms CPU solutions in terms of packet throughput and delay, and has strong delay stability. Therefore, FPGAs have obvious advantages over CPUs when performing large data processing tasks with high repetition rates.By programming the FPGA, the user can change the internal connection structure of the chip at any time to realize any logic function. Especially in industries with immature technical standards or rapid development and change, FPGA can effectively help enterprises reduce investment risks and sunk costs, and is a functional and economical choice. Figure 5. Computer GPU With the evolution of intelligent market demand, highly customized chips (ASIC SoC) have led to a sharp increase in market risks due to the large scale of non-repetitive investment and long R&D cycle. Relatively speaking, FPGA has advantages in the field of parallel computing tasks, and can replace some ASICs in the field of high performance and multi-channel. The demand for multi-channel computing tasks in the field of artificial intelligence (AI) drives the evolution of FPGA technology to the mainstream. Figure 6. ASIC SoC Ⅱ Five Advantages of FPGA 2.1 Performance Taking advantage of hardware parallelism, FPGAs break the sequential execution model and complete more processing tasks per clock cycle, surpassing the computing power of digital signal processors (DSPs). BDTI(Big Data Test Infrastructure), a well-known analysis and benchmarking company, has published benchmarks that show that in some applications, FPGAs can handle many times more processing power per dollar than DSP solutions. Controlling input and output (I/O) at the hardware level provides faster response times and specialized functionality to meet application needs. 2.2 Time-to-Market Despite increasing time-to-market constraints, FPGA technology offers flexibility and the ability to rapidly prototype. Users can test an idea or concept and complete verification in hardware without going through the lengthy manufacturing process of custom ASIC design. This allows users to make incremental modifications and iterate FPGA designs in hours, saving weeks. Commercial off-the-shelf (COTS) hardware provides different types of I/O connected to user-programmable FPGA chips. The increasing popularity of high-level software tools reduces the learning curve and abstraction layers, and often provides useful IP cores (pre-built functions) for advanced control and signal processing. 2.3 Cost The non-recurring engineering (NRE) cost of custom ASIC design far exceeds the cost of FPGA-based hardware solutions. The huge initial investment in ASIC design shows that OEMs need to ship thousands of chips each year, but more end users need custom hardware capabilities that enable the development of tens to hundreds of systems. The nature of programmable chips means that users can save on manufacturing costs as well as long lead times for assembly. System requirements change from time to time, but the cost of changing the FPGA design is negligible compared to ASCI's huge expense. 2.4 Stability Software tools provide the programming environment, and FPGA circuits are the real "hard" implementation of programming. Processor-based systems often contain multiple layers of abstraction that can schedule tasks and share resources among multiple processes. The driver layer controls hardware resources, while the operating system manages memory and processor bandwidth. For any given processor core, only one instruction can be executed at a time, and processor-based systems face the risk of tightly time-bound tasks taking over each other at all times. FPGAs, on the other hand, do not use an operating system, and have true parallel execution and deterministic hardware that focuses on each task, reducing the chance of stability issues. 2.5 Long-Term Maintenance As mentioned above, FPGA chips are field-upgradable without the time and expense involved in redesigning ASICs. For example, digital communication protocols contain specifications that can change over time, and ASIC-based interfaces can create maintenance and forward compatibility difficulties. Reconfigurable FPGA chips can accommodate future modifications. As a product or system matures, users can enhance functionality without spending time redesigning hardware or modifying board layouts.   Ⅲ New Applications of FPGA At present, the FPGAs mainly produced by Xilinx and Altera with the highest market share, which are all based on SRAM technology, and need to be connected to an external memory to save the program when in use. When powered on, the FPGA reads the data in the external memory into the on-chip RAM, and after completing the configuration, it enters the working state. When power off, the FPGA returns to a white chip, and the internal logic disappears. In this way, the FPGA can not only be used repeatedly, but also does not require a special programmer, but only a general EPROM and PROM programmer. So Actel, QuickLogic and other companies also provide FPGAs with anti-fuse technology, which can only be downloaded once. They have the advantages of anti-radiation, high & low temperature resistance, low power consumption and fast speed. They are widely used in military and aerospace fields. FPGA cannot be erased and written repeatedly, which is troublesome and expensive in the early stage of development. Lattice is the inventor of ISP technology, which has certain characteristics in small-scale PLD applications. Early Xilinx products generally did not involve military and aerospace markets, but now a number of products such as Q Pro-R have entered such fields.In the industrial field, FPGA chips are widely used in the industrial field, and are widely used in video processing, image processing, CNC machine tools and other fields to realize signal control and operation acceleration functions. With the development of intelligence and automation technology, the industrial field is gradually shifting from human resources as the core element to intelligent unmanned factories with automation as the core element.Smart electric vehicles will be the mainstream development direction of the automotive industry in the future. At present, the application of FPGA in automotive cameras and sensors is relatively mature. In the artificial intelligence system of automatic/intelligent driving vehicles, the applicability of FPGA will be the most suitable for processing sophisticated ADAS and autonomous driving. Figure 7. FPGA for Auto In the field of automotive electronic system interface and control, FPGA chips are used to control and drive electric vehicle motor control systems, connect various in-vehicle equipment such as driving systems, instrument panels, radar, ultrasonic sensors, etc. control. In the field of video bridging and fusion, FPGA chips can be used to realize functions such as signal bridging of multiple image sensors, 3D surround view video fusion, reversing auxiliary video, and assisted driving video.In the field of communication, the number of 5G base stations has increased, and the FPGA usage of a single base station has increased, driving the increase in FPGA demand. According to estimates, the FPGA consumption of a 5G single base station is expected to increase from 1-3 blocks in the 4G period to 4-5 blocks in the 5G period. Figure 8. RFSoC FPGA Board Target 5G eFPGA technology is superior to traditional FPGA solutions in terms of performance, cost, power consumption, profitability, etc., and can provide flexible solutions for different application scenarios and different market segments. The economic trend of increasing design complexity and falling equipment costs has stimulated the market demand for eFPGA technology.   Ⅳ Development Trend of FPGA First of all, with the commercialization of the new generation of communication technology, the demand for products such as communication base stations, servers, and intelligent terminals will further expand, thereby driving the increase in the market demand for FPGA chips. At the same time, smart cities, smart factories, and consumer electronics pay more attention to the functionality of various smart IoT devices, which will drive the wide application of FPGA chips in smart IoT devices. With the development of the Internet of Vehicles technology, the scale of the use of FPGA chips in the automotive industry will increase day by day to build a more complete Internet of Vehicles and realize smarter autonomous driving functions. Therefore, with the rapid penetration of 5G, the vigorous development of AI and the increasing trend of automotive intelligence, it is expected that the demand for FPGAs in the three fields of communication, AI and automotive electronics will continue to increase in the future, which will also promote The FPGA industry continues to grow.   Ⅴ FAQ 1. What is FPGA and why it is used?The acronym FPGA stands for Field Programmable Gate Array. It is an integrated circuit that can be programmed by a user for a specific use after it has been manufactured. ... These blocks create a physical array of logic gates that can be customized to perform specific computing tasks. 2. Is FPGA faster than GPU?The difference between GPU and FPGA performance is not a static factor, but it does depend on the size of the data set. A study by Sanaullah and Herbordt [7] revealed that FPGA can compute small samples of 3D FFT tens of times faster than GPU. The difference is less clear when the data set gets bigger. 3. Is FPGA faster than CPU?A FPGA can hit the data cell faster and more often than a CPU can do it meaning the FPGA causes more results to occur during an attack. It all goes faster when an FPGA is used. And as a side benefit, no trace of all this is left on the CPU because it's never touched when an FPGA is used. 4. Are FPGAs efficient?Efficiency and Power: FPGAs are well-known for their power efficiency. A research project done by Microsoft on an image classification project showed that Arria 10 FPGA performs almost 10 times better in power consumption. 5. Is FPGA programming hard?FPGA vendors have touted their wares as ideal replacements for DSPs, CPUs, and GPUs – even for all of them in a single device – but they are notoriously difficult for software engineers to program as they are not anything like a conventional processor. 6. What can you do with FPGAs?Uses for FPGAs cover a wide range of areas—from equipment for video and imaging, to circuitry for computer, auto, aerospace, and military applications, in addition to electronics for specialized processing and more. 7. What is the difference between processor and FPGA?Microprocessor vs FPGA: A microprocessor is a simplified CPU or Central Processing Unit. ... An FPGA doesn't have any hardwired logic blocks because that would defeat the field programmable aspect of it. An FPGA is laid out like a net with each junction containing a switch that the user can make or break. 8. What language is used to program FPGA?VerilogTraditionally, FPGAs are programmed using pro-level hardware-description languages such as Verilog or VHDL. 9. How many times can you program an FPGA?There is effectively no limit to the number of times a device can be reconfigured; the configuration is stored in SRAM, which has no write limit. most Fpgas can be passively loaded from a processor, one word at a time. That processor can get the FPGA image from anywhere. 10. What are the advantages of FPGA?FPGA advantagesLong-term availabilityUpdating and adaptation at the customerVery short time-to-marketFast and efficient systemsAcceleration of softwareReal-time applicationsMassively parallel data processing 11. How do you make an FPGA?FPGA design checklistMake sure you have plenty of time to spare.Find a decent computer.If you can afford it, add a big display.Decide which operating system to use.Consider using a virtual machine (VM).Select an FPGA vendor.Pick out a suitable development board.Select an embedded processor to use. 12. What is FPGA for beginners?FPGA stands for Field Programmable Gate Array. As you may already know, FPGA essentially is a huge array of gates that can be programmed and reconfigured any time anywhere. Huge array of gates is an oversimplified description of FPGA. FPGA is indeed much more complex than a simple array of gates. 13. What is FPGA in Verilog?FPGAs are nothing, but reconfigurable logic blocks and interconnects can be programmed by Hardware Description Language like Verilog/ VHDL to perform a specific functionality. 14. Do we need to program the FPGA once powered off?If you have a SRAM-based FPGA, like the Spartan 3, then you have to program it each time it is powered up. The reason for this is that the SRAM which stores the configuration is volatile and loses the programmed configuration after power is switched off. 15. How is FPGA different from microcontroller?One of the main differences between a microcontroller and an FPGA is that an FPGA doesn't have a fixed hardware structure, while a microcontroller does. While FPGAs include fixed logic cells, these, along with the interconnects, can be programmed in parallel by using HDL coding language.

Ⅰ IntroductionThis article focuses on the electronic component known as the Optocoupler. (For the fiber-optic networking component, please refer to Optical Isolators). This guide covers the fundamentals of optocouplers, their working principles, specifications, and practical examples of how to implement them in your circuits.Optocoupler Related VideoVideo: How an Optocoupler Works and Example CircuitⅡ Photocouplers, Opto-couplers & Opto-isolatorsThese devices are known by a variety of names, including optoisolator, photocoupler, and optocoupler.An optocoupler is a semiconductor device that transmits an electrical signal between two isolated circuits using light. This process ensures there is no direct electrical connection between the input (source) and the output (load), effectively protecting sensitive low-voltage components.While often used interchangeably, there is a technical distinction in the industry:Optocoupler: Typically refers to devices used to transfer analog or digital information between circuits with voltage differentials below 5,000 Volts.Optoisolator: Often refers to devices specifically designed to withstand very high voltage differentials (5,000V to 50,000V+) for safety isolation in power systems.Optocouplers are typically housed in small packages ranging from standard DIP (Dual Inline Package) to tiny SMD (Surface Mount Device) packages. Despite their small size, they play a massive role in linking data, optical encoding, and detecting position transitions on encoder wheels.They are also the core technology inside Solid-State Relays (SSR), allowing low-power logic signals to switch high-power AC or DC loads without any mechanical parts.Figure 1: Typical Photocouplers in DIP packagingⅢ Photocoupler / Optocoupler BasicsAn optocoupler consists of two main internal elements encased in a light-tight body:The Emitter: Usually a Near-Infrared LED (Light Emitting Diode) that converts the electrical input signal into light.The Detector: A photosensitive device (such as a phototransistor, photodiode, or TRIAC) that detects the light and generates an electrical output.These two components are separated by a transparent dielectric barrier (glass, plastic, or air gap). Because the connection is made via light photons rather than electrons, the input and output sides are electrically isolated. This isolation prevents high voltages or rapidly changing voltage spikes on one side from damaging components on the other.Ⅳ Optocoupler SymbolIn circuit diagrams, the optocoupler symbol illustrates its internal functionality. The left side typically shows the LED (Emitter), and the right side shows the receiver (Detector).Figure 2: Optocoupler circuit symbol (Phototransistor output)Common Variations:Phototransistor: The most common type for DC signal switching (shown above).Photo-Darlington: Uses a Darlington pair transistor for much higher gain (sensitivity) but slower switching speed.Photo-TRIAC / Photo-SCR: Used for controlling AC power mains.Figure 3: Photo-TRIAC circuit symbol (used for AC control)Ⅴ Optocoupler Specifications to WatchWhen selecting a component, consult the datasheet for these critical parameters:1. Current Transfer Ratio (CTR)This is the equivalent of "gain" (Beta) in a standard transistor. It is the ratio of the output collector current ($I_C$) to the input LED forward current ($I_F$), expressed as a percentage.Standard Phototransistor: CTR ranges from 10% to 100%.Photodarlington: CTR can range from 500% to 5000% (high sensitivity).Design Note - CTR Degradation: The efficiency of the internal LED decreases over time (aging). A good engineering practice is to design your circuit assuming the CTR will drop by 50% over the product's lifespan.2. Bandwidth and SpeedThis determines the maximum data rate.Phototransistors: Generally limited to about 250 kHz.Photodarlingtons: Slower, often limited to < 20 kHz due to long turn-off times.High-Speed Optocouplers: Devices like the 6N137 use a photodiode + logic amplifier architecture and can handle 10 MHz or more.3. Input Current ($I_F$)This is the current required to light up the internal LED. You must calculate a series resistor to limit this current, typically between 5mA and 20mA for standard devices.4. Isolation Voltage ($V_{iso}$)The maximum voltage difference the component can withstand between the input and output pins without electricity jumping the gap. Common ratings are 2500V to 5000V RMS.Ⅵ How It WorksThe operation is straightforward:Current is applied to the input side, flowing through the internal infrared LED.The LED emits infrared light inside the package. The intensity of this light is proportional to the input current.The light strikes the photosensitive base of the output transistor (or Triac).The photosensitive device "turns on" and conducts current.Figure 4: The internal light pathWhy is the Base pin unconnected?In many 6-pin optocouplers (like the 4N25), the base of the transistor is broken out to a pin (Pin 6). However, in most applications, this pin is left floating (unconnected) because the light serves as the base current. Connecting a resistor from the base to the ground can reduce sensitivity but increase switching speed.Figure 5: Effective isolation between Input and OutputⅦ Benefits and TypesPrimary Benefits:Ground Loop Elimination: Breaking the ground path between two circuits prevents hum and noise (critical in audio and instrumentation).Safety: Protects low-voltage microcontrollers (3.3V/5V) from high-voltage spikes (110V/220V).Level Shifting: Allows a 3.3V signal to switch a 24V or 48V circuit effortlessly.Common Types:Photo-Transistor: General-purpose DC switching.Photo-Darlington: High gain for very low input currents.Photo-SCR / Photo-TRIAC: Designed for interfacing with AC power mains.Logic Gate Output: (e.g., 6N137, H11L1) Includes internal logic buffers for high-speed digital communications.Figure 6: Common output configurationsⅧ Typical ApplicationsMicroprocessor I/O: Protecting GPIO pins on Arduinos or PLCs.Switch Mode Power Supplies (SMPS): Used in the feedback loop to maintain voltage regulation while keeping the mains side isolated from the low-voltage side.Motor Driving: Isolating the control logic from the noisy high-current motor drivers.Example: Triac Optocoupler for AC LoadsBy using a device like the MOC3020, a 5V digital signal can trigger a large external Triac, which in turn controls an AC motor or lamp. Many Triac optocouplers feature Zero-Crossing Detection, which ensures the device only switches when the AC voltage is at zero, significantly reducing Electromagnetic Interference (EMI).Figure 7: A basic DC switching configurationⅨ Differences Between Optocouplers and Solid State Relays (SSR)While they operate on the same principle, the distinction lies in power capability and integration.Figure 8: Solid State Relays (SSRs)Optocouplers: Low power. Used for signal transmission. Usually requires external components (external Power Triacs or MOSFETs) to switch heavy loads.Solid State Relays: High power. They contain an optocoupler plus the high-power switching components and protection circuitry inside a single, larger block. They can switch tens of Amps directly.Ⅹ How to Use an Optocoupler with ArduinoConnecting a load directly to an Arduino is risky. If the load is a motor or a solenoid, "flyback" voltage spikes can destroy the microcontroller. Using an optocoupler like the 4N25 or PC817 resolves this.The Circuit Concept:The Arduino drives the internal LED of the optocoupler. The optocoupler's output transistor acts as a switch for the secondary circuit.Figure 9: 4N25 OptocouplerWiring Guide (4N25 to Arduino):1. Input Side: Connect Arduino Pin -> 220Ω Resistor -> Optocoupler Pin 1 (Anode). Connect Pin 2 (Cathode) to Arduino GND.2. Output Side: Connect the device you want to control. Important: If you are using the optocoupler to send a signal into another digital pin, you must use a Pull-up Resistor on the collector (Pin 5) because the phototransistor can only pull voltage down to ground; it cannot "source" voltage effectively.Figure 11: Basic wiring diagram for isolating a signalⅪ FAQ1. What are the disadvantages of an optocoupler?The main disadvantages are speed and power handling. Standard optocouplers have a relatively slow frequency response compared to digital isolators. Also, the output phototransistor cannot handle high currents directly; it usually requires an external transistor or relay to switch heavy loads.2. Is an optocoupler the same as a relay?Not exactly. While both isolate circuits, a mechanical relay uses a physical electromagnet and moving contacts (clicking sound). An optocoupler uses light and has no moving parts. Optocouplers are faster and last longer but handle much less current than relays.3. How do you use an optocoupler for analog signals?While mostly used for digital switching, linear optocouplers exist. To send audio or analog data, you set up a specific bias current (standing current) through the LED and modulate that current with your signal. Specialized "Linear Optocouplers" use feedback photodiodes to linearize the output.4. How do I ensure the optocoupler switches fully (Saturation)?To use an optocoupler as a solid switch, you must drive it into "saturation." This means ensuring the input current ($I_F$) is sufficient and the output collector load resistor is high enough so that the phototransistor turns completely on. Always check the CTR curve in the datasheet.5. Are optocouplers analog or digital?They are fundamentally analog devices (light intensity varies with current), but they are most commonly used in digital applications (On/Off switching). Specialized high-speed digital optocouplers (logic-output) are available specifically for data transmission. ul { margin-bottom: 20px; } li { margin-bottom: 10px; } .caption { text-align: center; font-size: 14px; color: #7f8c8d; margin-top: -15px; margin-bottom: 25px; font-style: italic; } .note-box { background-color: #e8f6f3; border-left: 5px solid #1abc9c; padding: 15px; margin: 20px 0; font-size: 16px; } .warning-box { background-color: #fff3cd; border-left: 5px solid #ffc107; padding: 15px; margin: 20px 0; } strong { color: #d35400; } .faq-item { margin-bottom: 20px; background: #fff; padding: 15px; border: 1px solid #eee; border-radius: 5px; } .faq-question { font-weight: bold; color: #e67e23; font-size: 18px; display: block; margin-bottom: 10px; }

Introduction In this lesson, we'll look at what a servo motor is and how it works. First, let's define what a servo motor is and look at some of the unique characteristics of the different types of servo motors and their applications. You will also learn how to control Servo Motors with an Arduino and a Raspberry Pi in this blog. Introduction Ⅰ What is a Servo Motor? Ⅱ Servo Motor Related Video: Ⅲ Types of Servo Motors 3.1 AC or DC 3.2 Brushed or Brushless 3.3 Synchronous or Asynchronous Ⅳ Servo Motor Working Principle Ⅴ Applications of Servo Motors Ⅵ Difference Between Stepper Motor and Servo Motor  Ⅶ Servo Motors Control with an Arduino  7.1 Experiment 1 Ⅷ Control with  Raspberry Pi 8.1 PWM (Pulse Width Modulation) 8.2 Components Required 8.3 Circuit Diagram 8.4 Working and Programming Explanation 8.5 Code Ⅸ FAQ   Ⅰ What is a Servo Motor? A servo motor is a self-contained electrical device that rotates machine parts with high efficiency and precision. This motor's output shaft can be moved to a specific angle, position, and velocity that a standard motor cannot. The Servo Motor  combines a standard motor with a sensor to provide positional feedback. The most important component of the Servo Motor  designed and used specifically for this purpose is the controller  . Figure1:Servo Motor      Ⅱ Servo Motor Related Video:   How servo motor works   Servo Motor Video Description: This movie gives an overview of how RC servo motor works and how it's made.   Ⅲ Types of Servo Motors Servo motors are classified into two types based on their application: AC servo motors  and  DC  servo motors. There are three major factors to consider when evaluating servo motors. The first type of consideration is the current type –  AC  or  DC – and the second type of consideration is the type of commutation used, whether the motor uses brushes. The third type of consideration is the motor's rotating field, the rotor, and whether the rotation is synchronous or asynchronous.   3.1 AC or DC Let's start with the first servo consideration. The most fundamental classification of a motor is based on the type of current it will use. When it comes to performance, the primary distinction between  AC and DC motor  s is their inherent ability to control speed. Figure2:DC or AC Servo Motor  With a constant load, the speed of a DC motor  is directly proportional to the supply voltage. The frequency of the applied voltage and the number of magnetic poles determine the speed of an alternating current motor.   Figure3:DC or AC Servo Motor  While both AC and DC motor  s are used in servo systems, AC motors  can handle more current and are more commonly used in servo applications such as robots, in-line manufacturing, and other industrial applications requiring high repetitions and precision.   3.2 Brushed or Brushless The next step is to decide whether to use a brushed or brushless finish. A DC Servo Motor  can be commutated mechanically with brushes, electronically without brushes, or mechanically with a commutator. Brushed motors are less expensive and easier to operate in general, whereas brushless designs are more reliable, have higher efficiency, and are quieter.   Figure4:brushed or brushless Servo Motor  A commutator is a rotary electrical switch that reverses the current direction between the rotor and the drive circuit on a regular basis. It is made up of a cylinder made up of multiple metal contact segments on the rotor. Two or more electrical contacts known as "brushes" made of a soft conductive material such as carbon press against the commutator, making sliding contact with commutator segments as it rotates. Figure5:brushed or brushless Servo Motor  While the majority of servo motors are AC brushless designs, brushed permanent magnet motors are occasionally used as servo motors due to their simplicity and low cost. The permanent magnet DC motor  is the most common type of brushed DC motor  used in servo applications. Figure6:brushed or brushless Servo Motor  Brushless DC motors replace the physical brushes and commutator with an electronic commutation method, typically using Hall effect sensors or an encoder. Figure7:brushed or brushless Servo Motor  AC motors are generally brushless, though some designs do have brushes and are mechanically commutated, such as the universal motor, which can run on either AC or DC power. Figure8:brushed or brushless Servo Motor      3.3 Synchronous or Asynchronous While DC motor  s are generally classified as brushed or brushless, AC motors  are often distinguished by the rotational speed of their synchronous or asynchronous field. If we recall from the AC-DC discussion, the frequency of the supply voltage and the number of magnetic poles determine the speed of an AC motor. This speed is known as the synchronous speed. As a result, in a synchronous motor, the rotor rotates at the same rate as the rotating magnetic field of the stator. Figure9:synchronous or asynchronous Servo Motor  In an asynchronous motor, also known as an induction motor, the rotor rotates at a slower rate than the stator's rotating magnetic field. However, the speed of an asynchronous motor can be varied using a variety of control methods, including changing the number of poles and changing the frequency, to name a few. Figure10:synchronous or asynchronous Servo Motor      Ⅳ Servo Motor Working Principle A servo is made up of a motor (either DC or AC), a potentiometer, a gear assembly, and a control circuit. First and foremost, we use gear assembly to reduce RPM and increase motor torque. Assume that at the initial position of the servo motor shaft, the position of the potentiometer knob is such that no electrical signal is generated at the potentiometer's output port. An electrical signal is now applied to the error detector amplifier's other input terminal. The difference between these two signals, one from the potentiometer and one from other sources, will now be processed in a feedback mechanism and output will be provided in the form of an error signal. This error signal serves as the motor's input, and the motor begins to rotate. The motor shaft is now connected to the potentiometer, and as the motor rotates, so does the potentiometer, generating a signal. As a result, as the potentiometer's angular position changes, so does its output feedback signal. After a while, the position of the potentiometer reaches a point where the output of the potentiometer is the same as the external signal provided. There will be no output signal from the amplifier to the motor input because there is no difference between the externally applied signal and the signal generated at the potentiometer in this condition, and the motor will stop rotating. Figure11:synchronous or asynchronous Servo Motor    Ⅴ Applications of Servo Motors Servo Motors are used in a variety of applications, some of which are listed below:In robotics, the servo motor is used to activate movements, giving the arm its precise angle.The servo motor is used to start, move, and stop conveyor belts that transport the product through multiple stages. As an example, consider product labeling, bottling, and packaging.The servo motor is built into the camera to correct a lens and improve out-of-focus images.In a robotic vehicle, the servo motor is used to control the robot wheels, producing enough torque to move, start, and stop the vehicle as well as control its speed.In a solar tracking system, the servo motor is used to correct the angle of the panel so that each solar panel faces the sun.The servo motor is used in metal forming and cutting machines to provide milling machines with precise motion control.Textiles use servo motors to control spinning and weaving machines, knitting machines, and looms.The Servo motor is used in automatic door openers in public places such as supermarkets, hospitals, and theaters to control the door.   Ⅵ Difference Between Stepper Motor and Servo Motor  Comparison Chart Basis for ComparisonStepper MotorServo MotorBasicStepper motor operates in steps.It is continuous operating machine.System configurationOpen loopClosed loopPower requirementMoreComparatively lessDesignSimpleComplexAbility to responseHighComparatively lowCostInexpensiveExpensiveReliabilityMoreLessNoise and vibrationHighComparatively lessOperating speedSlowFastFeedback mechanismNot existExistHeat generationMoreComparatively lessNumber of polesGenerally 50 to 150Around 4 to 12Life spanMoreLessDamage due to overloadLess prone to get damaged.Comparatively more prone to get damaged.Torque producedHighLowEfficiencyLessMoreTolerance towards moment of inertiaHighLowApplicationsIn gaming, textile, welding machineries, medical and 3D printing equipments, etc.In robotics, antenna positioning systems, automatic doors, cameras, remote controlled equipments, etc. Ⅶ Servo Motors Control with an Arduino  You can connect small servo motors directly to an Arduino  to control the shaft position very precisely. Most servo motors have the following three connections: Black/Brown ground wire.Red power wire (around 5V).Yellow or White PWM wire. In this experiment, the power and ground pins will be connected directly to the Arduino  5V and GND pins. The PWM input will be connected to a digital output pin on the Arduino,  7.1 Experiment 1 Hardware Required1 x TowerPro SG90 servo motor1 x Arduino  Mega25603 x jumper wires   Wiring Diagram The best thing about servo motors is that they can be directly connected to an  Arduino ,  Connect the motor to the Arduino  in the manner shown in the table below: Servo red wire – 5V pin Arduino          Servo brown wire – Ground pin Arduino          Servo yellow wire – PWM(9) pin Arduino  Caution: Do not try to rotate the servo motor by hand, as you may damage the motor.     Figure12: Wiring Diagram Code When the program starts, the servo motor will slowly rotate from 0 to 180 degrees, one degree at a time. When the motor has rotated 180 degrees, it will start rotating in the opposite direction until it reaches the home position. #include //Servo library Servo servo_test; //initialize a servo object for the connected servo int angle = 0; void setup() { servo_test.attach(9); // attach the signal pin of servo to pin9 of arduino} void loop() { for(angle = 0; angle < 180; angle += 1) // command to move from 0 degrees to 180 degrees { servo_test.write(angle); //command to rotate the servo to the specified angle delay(15); } delay(1000); for(angle = 180; angle>=1; angle-=5) // command to move from 180 degrees to 0 degrees { servo_test.write(angle); //command to rotate the servo to the specified angle delay(5); } delay(1000);} Ⅷ Control with  Raspberry Pi In this tutorial, we will use the Raspberry Pi  to control a servo motor. Before we get to the servo, let's talk about PWM because it's the basis for controlling a servo motor.   8.1 PWM (Pulse Width Modulation) PWM is an abbreviation for 'Pulse Width Modulation.' PWM is a technique for obtaining variable voltage from a steady power supply. Consider the circuit below to better understand PWM.   Figure13:PWM   In the figure above, if the switch is closed continuously for a period of time, the LED will be 'ON' during that time. If the switch is closed for half a second and then opened for the next half a second, the LED will be turned on only for the first half a second. The percentage of time the LED is on over the total time is known as the  Duty Cycle , and it can be calculated as follows:   Duty Cycle =Turn ON time/ (Turn ON time + Turn OFF time) Duty Cycle = (0.5/ (0.5+0.5)) = 50% As a result, the average output voltage will be 50% of the battery voltage. When we increase the ON and OFF speed to a certain level, the LED will dim instead of being ON and OFF. This is because our eyes cannot clearly detect frequencies higher than 25Hz. Consider a 100ms cycle with an LED that is off for 30msec and on for 70msec. We will have 70% stable voltage at the output, so the LED will glow continuously at 70% intensity. The Duty Ratio ranges from 0 to 100. '0' denotes complete inactivity, while '100' denotes complete activation. This Duty Ratio is critical for Servo Motor,  This Duty Ratio determines the position of the Servo Motor,    8.2 Components Required We're running Raspbian Jessie on a Raspberry Pi  2 Model B. All of the basic hardware and software requirements have already been discussed, and you can find them in the Raspberry Pi  Introduction; however, we will need: Connecting pins 1000uF capacitor SG90  Servo Motor  Breadboard   8.3 Circuit Diagram Figure14:Circuit Diagram If A1000F is not connected across the +5V power rail, the  PI  may shut down unexpectedly while controlling the servo.   8.4 Working and Programming Explanation Once everything is connected according to the circuit diagram, we can power on the  PI and begin writing the program in PYHTON. We will go over a few commands that we will use in the PYHTON program. We will import a GPIO file from the library, and the function below will allow us to program the GPIO pins on the PI. We're also renaming "GPIO" to "IO," so in the program, whenever we refer to GPIO pins, we'll say "IO." import RPi.GPIO  as IO When the GPIO pins that we are attempting to use are performing other functions. In that case, we'll get warnings while running the program. The following command instructs the PI to disregard the warnings and continue with the program. IO.setwarnings(False) We can refer to the GPIO pins of the PI by either their pin number on the board or their function number. On the board, for example, 'PIN 29' is 'GPIO5'. So we specify whether we want to represent the pin here by '29' or '5'. IO.setmode (IO.BCM) PIN39 or GPIO19 is selected as the output pin. This pin will provide PWM output. IO.setup(19,IO.OUT) After we have set the output pin, we must configure it as a PWM output pin. p equals IO. Power-Wave Modulation (PWM) (output channel, frequency of PWM signal) The above command is for configuring the channel as well as the frequency of the channel." 'p' is a variable that could be anything. We'll use GPIO19 as the PWM "Output channel," and the "Frequency of PWM signal" will be 50, because the SG90's working frequency is 50Hz. The command below is used to initiate PWM signal generation. 'DUTY CYCLE' is used to specify the 'Turn On' ratio, as previously explained. p.start(DUTYCYCLE) The following command is used to create a forever loop, which means that the statements inside the loop will be executed indefinitely.   8.5 Code import RPi.GPIO  as IO        # calling for header file for GPIO’s of PI import time                           # calling for time to provide delays in program IO.setwarnings(False)          # do not show any warnings IO.setmode (IO.BCM)            # programming the GPIO by BCM pin numbers. (like PIN29 as‘GPIO5’) IO.setup(19,IO.OUT)             # initialize GPIO19 as an output p = IO.PWM  (19,50)              # GPIO19 as PWM output, with 50Hz frequency p.start(7.5)                             # generate PWM signal with 7.5% duty cycle while 1:                                                       # execute loop forever                                             p.ChangeDutyCycle(7.5)                   # change duty cycle for getting the servo position to 90º         time.sleep(1)                                      # sleep for 1 second         p.ChangeDutyCycle(12.5)                  # change duty cycle for getting the servo position to 180º         time.sleep(1)                                     # sleep for 1 second         p.ChangeDutyCycle(2.5)                  # change duty cycle for getting the servo position to 0º         time.sleep(1)                                     # sleep for 1 second   Ⅸ FAQ 1. Are servo motors AC or DC? AC servo motors depend on an AC power source whereas DC Servo motors depend on DC power source (like Batteries). AC servo motors performance is dependent upon voltage as well as frequency whereas DC servo motors performance mainly relies upon voltage alone. 2. Can servo motors rotate 360? The position of the servo motor is set by the length of a pulse. ... The end points of the servo can vary and many servos only turn through about 170 degrees. You can also buy 'continuous' servos that can rotate through the full 360 degrees. 3. Which motor is used in servo motor? While the majority of motors used in servo systems are AC brushless designs, brushed permanent magnet motors are sometimes employed as servo motors for their simplicity and low cost. The most common type of brushed DC motor used in servo applications is the permanent magnet DC motor.