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Catalog IntroductionHardware componentsSoftware componentsHardware SpecificationsSoftware SpecificationsReference codeConclusionIntroductionParking is a major issue in today's contemporary, congested cities. Simply put, there are too many vehicles on the road and not enough parking spaces. As a result, efficient parking management solutions are increasingly necessary. As a result, we demonstrate how to set up a parking management system based on IOT that promotes efficient parking space utilization. To demonstrate the concept, we use IR sensors to detect parking space occupancy and a DC motor to simulate gate opening motors. We presently use an AVR microcontroller and a Wi-Fi modem to link the system to the internet. We use IOTGecko for internet connectivity and GUI design for IOT administration. The system determines whether parking spaces are occupied using IR sensors. To open the gate automatically when a car is detected on the fence, it also uses IR technology. The technology reads the number of parking spaces that are available and updates data with the cloud server to enable online parking slot availability checks. Customers can now check the availability of parking spaces online from any place to find parking without fuss. As a result, the system gives users access to a powerful IOT-based parking management system while also helping cities find a solution to their parking issues. An IoT (Internet of Things) based smart parking system is a technology solution that utilizes sensors, cameras, and other IoT devices to streamline the process of finding and reserving parking spots in each area. These systems can be deployed in a variety of settings, including urban areas, airports, shopping malls, and university campuses, to name a few. One of the primary benefits of an IoT based smart parking system is that it helps to reduce the time and frustration associated with finding a parking spot. By providing real-time information about the availability of parking spaces, these systems can direct drivers to open spots, saving them the hassle of driving around aimlessly searching for a place to park. The cameras in the system can also be used to monitor and enforce parking regulations, such as time limits and restricted areas.Hardware componentsThe hardware components of an IoT based smart parking system include sensors, such as infrared (IR) sensors, which are used to detect the presence of a vehicle in a particular parking space. The system may also include DC motors, which can be used to move physical barriers or gates to allow or block access to parking spaces. Other hardware components include an AT mega microcontroller, which serves as the brain of the system and coordinates all the other components, an LCD display, which can be used to provide information to drivers, and a power supply, which powers all the system's components. Software componentsIn addition to hardware components, an IoT based smart parking system also requires a robust and reliable network infrastructure. This may include a Wi-Fi modem, which allows the system to connect to the internet and transmit and receive data in real-time. The system may also include various ICs (integrated circuits), resistors, capacitors, LEDs (light emitting diodes), and diodes, which are used to control and regulate the flow of electricity within the system. The software components of an IoT based smart parking system are equally important. These may include the Arduino compiler, a popular tool for programming microcontrollers, and the C programming language, which is often used to write the code that runs on these systems. Another software tool that may be used is IOTGecko, a platform for building and deploying IoT applications. One of the challenges of implementing an IoT based smart parking system is the cost of the initial investment, as these systems can be expensive to implement. However, many organizations that have implemented these systems have found that the long-term cost savings and benefits of these systems far outweigh the upfront costs.Hardware Specifications1IR sensors2DC Servo motors3AT mega Microcontroller4LCD Display5Power Supply6Wi-Fi Modem/Wi-Fi Module7Resistors8Capacitors9LED’s10Diodes Software SpecificationsArduino CompilerMC Programming Language: CIOTGeckoReference codeThe code is for reference only:  ConclusionIn conclusion, an IoT based smart parking system is a technology solution that utilizes sensors, cameras, and other IoT devices to streamline the process of finding and reserving parking spots. These systems can help to reduce the time and frustration associated with finding a parking spot, improve traffic flow, reduce congestion, and lower the overall cost of parking. While implementing these systems can be challenging, the long-term benefits often make it a worthwhile investment.

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.

Introduction The introduction of grounding technology was originally a protective way to prevent electrical or electronic equipment from being struck by lightning. At the same time, it is also an effective means to protect personal safety. When the phase line (such as poor wire insulation, aging, etc.)  touches the equipment shell for some reason, dangerous voltage will be generated on the equipment shell, thus the generated fault current will flow through the PE line to the ground, thus playing a protective role. With the development of electronic communication and other digital fields, only considering lightning protection and safety in the grounding system is far from meeting the requirements. Electrical Grounding Explained | Basic Concepts Catalog Introduction Ⅰ Basic: Q&A Related to Electrical Ground Ⅱ DC Power Supply Ground 2.1 Basic Overview 2.2 DC Power Supply Ground Analysis with Diagrams 2.3 Ground Bounce for Buck Converters 2.4 Ground Bounce for Boost Converters 2.5 Summery Ⅲ Useful Concepts for Grounding Analysis Ⅳ Conclusion Ⅴ FAQ Ⅰ Basic: Q&A Related to Electrical Ground The signal between each device needs a "ground" as the reference ground of the signal. Moreover, with the complexity of electronic equipment, the signal frequency is getting complicated. Therefore, in the grounding design, special attention must be paid to electromagnetic compatibility issues such as mutual interference between signals. Otherwise, improper grounding will seriously affect the reliability of system operation. Here the following are doubts that may arise in the power grounding. Q1: What is the definition of grounding?A: As for grounding concepts, to line engineers, the term usually means "reference point for line voltage". For system designers, it is often a cabinet or rack. For electrical engineers, it means green safety ground or connection to the earth. A more general definition is "A ground is a low impedance path for current to return to its source", and the key points are "low impedance" and "passage". Q2: What are the common grounding symbols in circuit?A: PE, PGND, FG-protective ground or chassisBGND or DC-RETURN-DC-48V (+24V) power supply (battery) returnGND: working groundDGND: digital groundAGND: analog groundLGND: lightning protection ground Q3: What is the appropriate grounding method?A: There are many ways to ground, including single-point grounding, multi-point grounding and mixed types of grounding. Among them, the single is divided into series single-point grounding and parallel single-point grounding. Generally speaking, single-point grounding is used for simple circuits, while grounding distinction between different functional modules, and multi-point grounding or multi-layer boards (complete ground plane layer) are used in low-frequency (f10MHz) circuits. Q4: Why should the analog ground and digital ground be separated?A: Both the analog signal and the digital signal return to the ground, the digital signal changes fast with large noise, while the analog signal needs a clean ground reference to work. If the analog and digital grounds are mixed, noise can affect the analog signal.According to the above mentioned, the analog ground and the digital ground should be processed separately, and then connected together through thin wires, or together at a single point. The general idea is to try to block the noise on the digital ground from flowing to the analog ground. Of course, this is not a very strict requirement that they must be separated, because it depends on the actual situation. Q5: How to ground the signal on the board?A: Under normal circumstances, it is best to use the nearest ground when designing, and after a complete multi-layer board design, it is very easy to ground common signals. The basic principle is to ensure the continuity of the traces and reduce number of vias, close to ground plane or power plane, etc. Q6: How to ground the interface devices of the board?A: Some single boards have external input and output interfaces, such as serial port connectors, network port connectors, etc, if they are not properly grounded, it will also affect normal work, such as network port interconnection errors, packet loss, etc., and will become an external source of electromagnetic interference, sending the noise inside the board to the outside. Generally speaking, an independent interface ground will be divided, and the connection with the signal ground will be connected by thin traces, and a o small resistance or 0ohm resistor can be connected in series. Thin traces can be used to block signal ground noise from passing to the interface ground. Similarly, the filtering of interface ground and interface power should also be carefully considered. Q7: How to ground the shielding layer in the cable with shielding layer?A: The layer of the shielded cable must be connected to the interface ground of the single board, not the signal ground. This is because there are various noises on the signal ground. If the shielding layer is connected to the signal ground, the noise voltage will drive the common mode current along the shielding. Therefore, cables with unreasonable design are generally the largest noise output source of electromagnetic interference.   Ⅱ DC Power Supply Ground 2.1 Basic Overview In power supply design, safety is often in the first place, and the same is true in switching power supplies. Grounding can protect the personal safety of users and ensure the normal operation of power equipment. So what is the appropriate grounding method in switching power supplies? What are the common ground symbols in circuits? This article will popularize the grounding basic in DC power supplies.DC-DC is a commonly used power supply circuit in electronic hardware design. It has high efficiency in realizing high input voltage and low output voltage. It is widely used, from power adapters, mobile phone chargers, and internal power conversion of electronic equipment to DC-DC circuits. Each semiconductor manufacturer has its own DC-DC chips, and also there are many optional chips. For a well-designed DC-DC circuit, not only the peripheral resistance, capacitance, but also the inductance parameters of the DC-DC circuit should be considered. There are also high requirements for the PCB layout design. This paper proposes a method to guide the grounding in the PCB layout from the perspective of the current flow in DC circuits. 2.2 DC Power Supply Ground Analysis with Diagrams Circuit grounding looks simple in a circuit schematic, but the actual characteristics of a circuit are determined by the layout of its PCB. And the analysis of the grounding point is very difficult, especially for the DC-DC converter circuit, the grounding point of the circuit will gather a large current that changes rapidly. When grounded nodes move, system performance suffers and the system radiates EMI. Here a good understanding of the physical nature of "ground" induced ground noise can provide an intuitive understanding of ground noise reduction problems.The change of the transmission current in the ground loop will generate a magnetic field in the loop. The magnetic field strength is proportional to the current, and the magnetic flux is proportional to the product of the loop area and the magnetic field strength, which is expressed by the formula: Figure 1. Right Hand Rule Suppose there is a sudden break in the current loop, as shown in Figure 2. When the switch is turned off, the magnetic flux disappears, which will generate a large transient voltage along the wire. If part of the wire is a grounding return pin, the voltage referenced to the ground level will have a spike, resulting in a false signal in any circuit that uses that pin as a ground reference. Figure 2. Function of Start Switch The traces on the PCB circuit board are not ideal wires and have resistance. 1 ounce (oz) copper has a resistance of 500 microohms/square, so a 1 amp change in current will only produce a bounce voltage of 500uV/square -- the problem only exists if you use long thin traces or daisy chain grounds or Precision electronic circuits.The best way to reduce ground bounce in a DC-DC switching circuit is to control the magnetic flux variation—minimizing current loop area and loop area variation. The principle of DC-DC circuit buck or boost is to use electronic switches to quickly switch to charge and discharge the energy storage element to achieve voltage conversion, and at the same time change the loop area of the current in the circuit, resulting in ground bounce and electromagnetic radiation.In some cases, as shown in Figure, the current remains constant, while the switching causes a change in the loop area and therefore a change in the magnetic flux. In switching state 1, an ideal voltage source is connected to an ideal current source through an ideal conductor. In addition, current flows in a loop that includes a ground return.In switch state 2, the same current flows in different paths when the switch changes position. The current source is DC and there is no change, but the loop area has changed. A change in the loop area means a change in the magnetic flux, so a voltage is generated. Because the ground loop is part of the change loop. Figure 3. Figure Loop Area In the case of switching changes, the loop area changes. Everywhere along the wire in the lower left, when the current I1 becomes 0, a voltage is generated where the magnetic field disappears. 2.3 Ground Bounce for Buck Converters The buck converter (step-down converter) circuit is very similar to the circuit structure in Figure 3 above, and the circuit of the step-down converter is simplified, as shown in Figure. Figure 4. Step-down Converter Circuit At high frequencies, a large capacitor such as the input capacitor Cin of the step-down converter can be regarded as a DC voltage source. Similarly, an inductor such as the output inductor LBuck can be regarded as a DC current source. These approximations help to visualize understanding and theoretical analysis.As shown in Figure 5, when the switch alternates between the two positions, the change in the path through which the current flows causes a change in the magnetic flux. The large inductor LBuck keeps the output current approximately constant. Similarly, the large capacitor Cin holds the voltage approximately equal to Vin. Since the voltage across the input lead inductance does not change, the input current also remains approximately constant. Figure 5. Effect of Switch on Loop Area Although the input current and output voltage are essentially constant, when the switch is switched from position 1 to position 2, the total loop area rapidly changes by half. Loop area changes imply rapid changes in magnetic flux, causing ground bounce along the loop circuit.In practice, a buck converter consists of a pair of semiconductor electronic switches, as shown in Figure 6. Although the complex procedure increases in each figure, the analysis method for ground bounce caused by changes in magnetic flux remains simple and intuitive. Figure 6. Magnetic Flux Changes Cause Ground Bounce The fact that changes in magnetic flux create voltages along the ground loop raises an interesting question: where is the real ground? Because ground bounce means that, to some ideal point called ground (that point needs to be defined), a bounce voltage is created on the ground return trace. In a power regulator circuit, the real ground should be connected to the low-voltage side of the load. After all, the purpose of a DC-DC converter is to provide a stable voltage and current to the load. All other points on the current loop are not true ground, but the part of ground loop.Since the low-voltage end of the load is grounded and the change in the loop area is the cause of the ground bounce, then reducing the ground bounce and electromagnetic radiation, and optimizing the grounding of the circuit are to minimize the current loop area in the DC-DC circuit. Here is a way to optimize the layout. For example, the location of the input capacitor, output capacitor, and energy storage inductor reduces the current loop area. Figure shows how to carefully place the input capacitor Cin to reduce the loop area and ground bounce. Figure 7. Reduce Ground Bounce Capacitor Cin in Figure bypasses the high-side switch on the top layer of the PCB directly to both ends of the bottom low-side switch, thereby reducing the variation in loop area and isolating it from the ground return. When the switch switches from one state to another, from the bottom of Vin to the bottom of the load, there is no loop area change or switch current change. Therefore no ground bounce occurs in the ground loop.Figure is an unreasonable PCB layout. When the high-side switch is turned on, the DC current flows along the red loop of the outer ring. When the low-side switch is turned on, the DC current flows along the blue loop. It can be seen that this circuit layout produces a large loop change when the switch changes, causing a change in the magnetic flux, resulting in ground bounce and electromagnetic radiation interference. Figure 8. Unreasonable Layout For the clarity, in single-layer PCB routing, even using a second-layer monolithic ground plane cannot solve the bounce caused by grounding. Figure 9 is a simple box to illustrate that the ground plane cannot solve the problem. Here we use a double layer PCB to add a bypass circuit at the top level power line vertical. Figure 9. Ground Floor In the Figure 9 (a), the ground plane is monolithic and uncut. The top layer print current flows through the capacitor, through the via, and to the ground plane. Because AC always flows along the path of least impedance, ground return current returns to the power source around the corners of its path. So when the amplitude or frequency of the current changes, the magnetic field of the current and its loop area change, thereby changing the magnetic flux. The regularity of current flow along the path of least impedance means that ground bounce can occur even with a monolithic ground plane - independent of its conduction.In the Figure 9 (b), a properly cut ground plane limits the return current to minimize loop area, thus greatly reducing ground bounce. Any residual ground bounce voltage developed within the cut return line is isolated from the common ground plane.The PCB layout in Figure 10 uses a double-layer PCB to mount the input capacitor and two switches on islands in the ground plane. This wiring doesn't have to be the best, but it works well and speaks to key points. It should be noted that the loop area surrounded by the red and blue currents is large, but the difference between the two loop areas is small. A small change in loop area means a small change in magnetic flux—small ground bounce. However, in general, keep the loop area small. Figure 10. is just to illustrate the importance of AC current path matching. Figure 10. Converter Layout   Additionally, ground bounce along any ground loop is limited by ground cutting within ground loop islands where magnetic fields and loop areas vary. Also, it may appear at first glance that the input capacitance Cin is not located between the top-level high-side switch and the lower-level low-side switch shown in Figure 10. Although physical proximity can be fine, what really works is the electronic proximity achieved by minimizing the loop area. 2.4 Ground Bounce for Boost Converters A boost converter (step-down converter) is actually a reflection of a buck converter, as shown in Figure 11, where the output capacitor must be placed between the top high-side switch and the bottom low-side switch to minimize loop area change. Figure 11. Changes in Loop Area In the same way that a buck converter places Cvin at a critical position, a boost converter places Cvout at a key position. 2.5 Summery The ground bounce voltage is mainly due to changes in the magnetic flux. In a DC-DC switching power supply, the magnetic flux variation is caused by switching the DC current at high speed between different current loop areas. But careful placement of the buck converter's input capacitors and the boost converter's output capacitors, and a good cut of the ground plane can isolate ground bounce. Pay attention to, it is important to be careful when cutting the ground plane to avoid increasing the loop area for other return currents in the circuit.Another reasonable layout should place the real ground on the bottom layer connecting the load, which will not cause changes in loop area or current. Any other point related to conduction can be called "ground", but it's just a point along the return path.   Ⅲ Useful Concepts for Grounding Analysis If you follow the basic concepts, you will have a clear idea of what will cause ground bounce. Figure 12. shows that two conductors that are perpendicular to each other are not subject to the mutual influence of the magnetic field. Figure 12. Two Conductors Perpendicular to Each Other   The magnetic field lines created around two parallel wires carrying equal currents in the same direction traditionally cancel each other out between the two wires, so the total energy stored by the two wires is less than the energy stored by one wire alone. Therefore, the inductance of PCB wide traces is smaller than that of narrow traces. Figure 13. Two Parallel Wires with Current Flowing in Same Directions   The magnetic field lines generated around two equal conductors carrying equal currents in opposite directions cancel each other out of the two conductors, and strengthen between the two conductors. If the inner loop area is reduced, so does 4the total magnetic flux. This phenomenon can explain why the return current of the AC ground plane always flows under the trace conductors on the top layer of the bath. Figure 14. Two Parallel Wires with Current Flowing in Opposite Directions Figure 15. shows why corners add inductance. A straight wire only sees its own magnetic field, but at the corners, the magnetic field of a vertical wire is also visible. Therefore, the corners store more magnetic field energy, and their inductance is greater than that of straight wires. Figure 15. Add Inductance at the Corners Figure 16. shows that cutting the ground plane under the transmission line conductor increases the loop area by diverting the loop current, thereby increasing the loop size and contributing to ground bounce. Figure 16. Return Current Flows Along the Path of Least Impedance   Figure 17. Effect of Component Orientation   Ⅳ Conclusion Ground bounce has always been a potential problem. For monitors or TVs, it means the image is noisy, for audio equipment it means the noise floor. In digital systems, ground bounce can cause calculation errors -or even system crashes. Careful estimation of parasitic elements and simulation are effective methods for predicting the magnitude of ground bounce.First, when designing the PCB, the low-voltage side of the load should be set to true ground. Then, replace the large inductors and capacitors with current and voltage sources to simplify the circuit dynamics. Observing the current loop under each switch combination, the loops should be made to overlap, and if this is not possible, an island should be carefully cut out in the ground plane to ensure that only islands of DC inflow and outflow are present.In most cases, good grounding performance can be obtained with these efforts. If that doesn't work, the resistance of the ground plane should be considered first, then the displacement currents flowing across all switches and parasitic capacitors entering the return path. In short, no matter what circuit, the principle is the same, that is, to reduce the loop area and its difference when the switch changes.   Ⅴ FAQ 1. Does power supply need to be grounded?While it will likely be fine (I've run many computers in old houses that had no grounding), it's not advised. A static charge will build up, and depending on where it discharges may cause damage to the electronics. 2. What is the purpose of a ground wire?The ground wire offers an additional path for the electrical circuit to flow into the earth so as to not endanger anyone working with the electricity nearby in the event of a short circuit. Without ground wire, your body could instead complete the ground path and may cause shock or electrocution. 3. Which wire is ground on power supply?In a DC circuit, the convention in most of the world is that black is the “ground” and any other color carries a signal or power rail of some sort, with red and yellow being popular for power wiring, but it can really be any color on any particular connector. For example, for a typical PC “ATX” power supply. 4. What is the purpose of a ground?Grounding gives electricity the most effective way to return to the ground via your electrical panel. A grounding wire gives an appliance or electrical device a safe way to discharge excess electricity. 5. Should you ground the negative of a DC power supply?As long as both the negative terminal of the LED and the negative terminal of the battery both have good enough connections to ground then the ground will carry enough current between the two connection to complete the circuit and light the LED. The same applies in the mains electricity supply. 6. How do I know if my power supply is grounded?Insert one probe of the circuit tester into the small slot and the other probe into the large probe. If the circuit tester lights up, you have power to the outlet. Now place one probe in the small slot and the other probe into the "U" shaped ground hole. The indicator should light up if the outlet is grounded. 7. Can you ground yourself by touching PSU?It looks pretty, but it's impossible to ground yourself to a case that has no bare metal. Instead, I just installed my power supply and touched the ground prong every now and then. All that said, if all you're doing is touching a metal part on the computer, you aren't really grounding yourself. 8. Can I tie the neutral and ground together?No, the neutral and ground should never be wired together. This is wrong, and potentially dangerous. When you plug in something in the outlet, the neutral will be live, as it closes the circuit. If the ground is wired to the neutral, the ground of the applicance will also be live. 9. What is ground in DC circuit?Traditionally, "ground" is the lowest potential in a circuit, e.g. the minus side of a battery or DC supply. 10. What happens when electricity goes to ground?The majority of the energy of the lightning discharge is dissipated in the air as it travels from the clouds to the ground through the air. The remainder is dissipated in the ground in the area surrounding the location of the strike, over a fairly short distance. 11. What is difference between earthing and grounding?Earthing and grounding are similar terms. ... The main difference between earthing and grounding is that the earthing refers that the circuit is physically connected to the ground with Zero Volt Potential. But, grounding refers that the circuit is not physically connected to ground, but still has zero potential. 12. Does a DC power supply need a ground?The answer comes from the NEC section 250.162, referring to the grounding of two-wire DC systems, which includes the 5V and 24V outputs, depending on your case. ... So, the short answer for a 24V DC system is no, the output is not required to be connected to ground. 13. How do you ground a DC power supply?You ground the device by connecting a grounding cable to earth ground and then attaching it to the grounding point on the DC power supply. You must provide the grounding cables. The cable lug used on the grounding cable should have a #10 stud hole and accommodate a minimum of 12-AWG wire.

ⅠIntroduction This project mainly introduces how to DIY a Simple Audio Player with  Amplifier LM386 . But before this project, it is very essential to know some basics of LM386. Therefore, the first of this article is about LM386 audio amplifiers and the second part we will have a look at the practical appliance of Simple Audio Player with Amplifier LM386. Catalog ⅠIntroduction Ⅱ Amplifier LM386 Related Video: Ⅲ LM386 Basics 3.1 LM386 Datasheet 3.2 LM386 Pinout 3.3 LM386 Features Ⅳ  Project Introduction 4.1 Hardware Required 4.2 Getting Ready with Your WAV Audio Files: 4.3 Circuit 4.4 Code 4.5 Working of this Arduino Music Player: Ⅴ FAQ How to make an LM386 audio amplifier circuit Amplifier LM386 Video Description: In this Video, We will explore how to use the popular LM386 class AB audio amplifier IC to build a simple mono 1 watt audio amplifier.  Ⅲ LM386 Basics Despite the fact that LM386 audio amplifiers are quite old. They do, however, have a lot of useful information. Assume your audio player has poor sound quality. You want to boost the volume. They are a good option. Because of the low voltage supply and the fact that it works well with a battery.   3.1 LM386 Datasheet You completed an audio circuit  . However, the sound is too faint. Many people use the LM386 to boost the sound to a speaker. The LM386 is a low-power audio amplifier. Also, you should be able to work with a battery,  It has a similar shape to  IC-741  and DIP-8. So, small and simple. Even if it's small, it makes a big sound. But...better. it's If you have previously read the LM386 Datasheet.   3.2 LM386 Pinout Figure1:pinout In DIP-8, we frequently use the LM386. There are only a few pin connections. Other packets are also the same. For example, SOP-8, TSSOP-8, and so on.   3.3 LM386 Features   Ⅳ  Project Introduction Including sounds or music in our project will always make it look and sound much more appealing. If you're working with an  Arduino  and have a lot of free spins, you can easily add sound effects to your project by purchasing an extra SD card module and a standard speaker. In this article, I'll show you how to play music and add sound effects with your  Arduino board, as well as introduce the IC LM386 Amplifier  , which we'll use in this process. We will play the.wav music files stored on an SD card in this project. The Arduino will be programmed to read these.wav files and play the audio on a speak through an LM386 Audio amplifier.   Figure2: Project     4.1 Hardware Required Arduino Due Board8-ohm speaker or headphonesArduino shield with an SD card with cs CS 4 (like the Ethernet shield)Components to build an external audio amplifierLM386 (low power audio amplifier)10 kohm potentiometer10 ohm resistor2 x 10 µF capacitor0.05 µF (or 0.1 µF) capacitor250 µF capacitor   4.2 Getting Ready with Your WAV Audio Files: The audio file to be stored on the SD card must be in.wav format and have 44100 Hz, 16-bit stereo quality. We need audio files in.wav format to play sounds from an SD card using Arduino because the Arduino Board can only play audio files in a specific format, which is wav format. There are many mp3 shields available for use with Arduino to create an Arduino mp3 player. Alternatively, to play mp3 files in Arduino, there are websites that will convert any audio file on your computer into that specific WAV file.   4.3 Circuit The shield is placed on top of the Due, and a micro-SD card is inserted into the slot. The card's root directory contains a.wav file called "test.wav." For a quick test, connect a pair of headphones to the ground and DAC0 while keeping the polarity in mind. To add a speaker to the board, connect an amplification circuit between the DAC0 pin and the speaker. The amplification circuit will boost the speaker's volume,  There are numerous audio amplifiers available, with the LM386 being one of the most common. The following scheme demonstrates how to construct the circuit using the LM386 and a variety of components. You can power the LM386 by connecting the Vs pin to various voltage sources, such as the +5 V on the Arduino Due's 5V pin or an external 9V  battery,  The capacitor is connected to pins 1 and 8 of the LM386 provides the amplifier's gain. The gain is set to 200 with the 10 F capacitor, and 50 without the capacitor. The volume of the amplifier can be adjusted using the potentiometer. Caution: Do not connect the speaker directly to the Arduino Due's pins.   Figure3 : Circuit   Figure4: LM386 mounting on breadboard   4.4 Code   4.5 Working of this Arduino Music Player: Simply press the button connected to pin 2 after programming your Arduino, and your Arduino will play the first song (saved as 1.wav) for you. You can now press the button again to change your track to the next song, 2.wav. Similarly, you can listen to all four songs. You can also play/pause the song by pressing the pin 3 button. Press it once to pause the song and once more to resume it from where it left off. Watch the video below to see the entire process in action (or maybe to relax with some songs). I hope you had a good time with the project. It is now up to your imagination to incorporate them into your projects. You can create a speaking clock, voice assistant, talking robot, voice alert security system, and many other things.   Ⅴ FAQ 1. How many watts is LM386? 700mW, mono, 5- to 18-V, analog input Class-AB audio amplifier. 2. How do you calculate LM386 gain? Voltage Gain Analysis: Without any external components, it has a gain of Gv = 2x15K/(150+1350) = 20 (26 dB). With a capacitor (or shortcutting) between pins 1 and 8 , it has a gain of Gv = 2x15K/150 =200 (46dB). 3. Is LM386 any good? The LM386 is a well-designed, basic workhorse that does a decent job when its hooves are kept clean and it's well-fed. Aside from having a slow op-amp stage by today's standards, it has decent performance. It can also sound horrible if you neglect it. 4. What is an audio amplifier circuit? The circuit of the audio amplifier consists of a transistor a device to apply the input signals and a speaker at the output. The transistors are connected based on the necessity. The important factors that need to be considered while designing a audio amplifier is gain,noise, frequency response and distortion. 5. Which amplifier can be used for audio amplifier? An audio power amplifier (or power amp) is an electronic amplifier that amplifies low-power electronic audio signals such as the signal from radio receiver or electric guitar pickup to a level that is high enough for driving loudspeakers or headphones. 6. What is the need of power amplifier? The function of a power amplifier is to raise the power level of input signal. It is required to deliver a large amount of power and has to handle large current. The characteristics of a power amplifier are as follows − The base of transistor is made thicken to handle large currents.

ⅠIntroduction The most common system is single-phase, which is mostly used in homes, whereas three-phase is commonly used in industrial or commercial buildings where heavy loads of power are required. Catalog ⅠIntroduction Ⅱ Three-phase Power Related Video: Ⅲ Single-phase AC Power Basics 3.1 What is Single-phase AC power? 3.2 Advantages of Single-phase 3.3 Disadvantages of Single-phase   Ⅳ 3-phase Power Explained 4.1 What is 3-phase Power? 4.2 Advantages of Three-Phase System 4.3 Disadvantages of Three-Phase System Ⅴ Why We Need 3-phase Power？ Ⅵ What Are the Differences Between Single-Phase Power and Three-Phase Power? Ⅶ FAQ   Ⅱ Three-phase Power Related Video: Three-Phase Power Explained   Three-phase Video Description: This video will take a close look at three-phase power and explain how it works. Three-phase power can be defined as the common method of alternating current power generation, transmission, and distribution. It is a type of polyphase system, and is the most common method used by electric grids worldwide to transfer power.   Ⅲ Single-phase AC Power Basics Single-phase electric power is the distribution of alternating current electric power using a system in which all of the supply voltages vary in unison. When the loads are mostly lighting and heating, with only a few large electric motors, single-phase distribution is used.   3.1 What is Single-phase AC power? Before delving into that topic, it's a good idea to first understand single-phase alternating current (AC). Single-phase alternating current (AC) power is delivered via a three-wire system consisting of one "hot" wire, one neutral wire, and one ground wire. With alternating current power, the power current or voltage reverses on a regular basis, flowing one way on the hot wire that supplies power to the load and the other way on the neutral wire. During a 360-degree phase change, a full power cycle occurs, and the voltage reverses itself 50 or 60 times per second, depending on the system in use in different parts of the world. It is 60 times or 60 hertz in North America (Hz). It is critical to note that the two current-carrying legs are always 180 degrees apart. Consider the power as riding a wave, specifically a sine wave with a defined frequency and amplitude. During each cycle, the waves on each wire pass through zero amplitude twice (see Figure 1). There is no power delivered to the load during these times. Figure1:Single-phase   These brief interruptions have no effect on residential and commercial building applications such as office environments, but they have serious consequences for the motors that power large machinery, as well as computers and other IT equipment.   3.2 Advantages of Single-phase Single-phase connections are designed for household supplies and residential homes. This is due to the fact that most appliances, such as televisions, lights, fans, refrigerators, and so on, require only a small amount of electricity to function.A single-phase connection works in a straightforward manner. It consists of a compact and lightweight unit in which the flow of electricity through the wires is reduced as the voltage increases.Because of the power reduction, it ensures that the power from a single-phase connection operates at peak efficiency and effectively transmits power.A single-phase connection is best suited for units rated up to 5 horsepower.   3.3 Disadvantages of Single-phase     Ⅳ 3-phase Power Explained Three-phase electric power (abbreviated 3), is a type of alternating current that is commonly used in power generation, transmission, and distribution. It is a type of polyphase system that uses three wires (or four if a neutral return wire is used) and is the most common method used by electrical grids around the world to transfer power.   4.1 What is 3-phase Power? As the name implies, three separate currents are provided by three-phase power systems, each separated by one-third of the time it takes to complete a full cycle. However, unlike single-phase, where the two hot legs are always 180 degrees apart, the currents in 3-phase are separated by 120 degrees. Figure 2 shows that when one line is at its peak current, the other two are not. When phase 1 reaches its positive peak, phases 2 and 3 are both at -0.5. In contrast to single-phase current, there is no point at which no power is delivered to the load. In fact, one of the lines is at a peak positive or negative position at six different points in each phase. In practice, this means that the total amount of power supplied by all three currents remains constant; there are no cyclical peaks and valleys as with single-phase. Many computers and motors used in heavy machinery are built with this in mind. Instead of having to account for the variation inherent in single-phase AC power, they can draw a steady stream of constant power. They use less energy as a result. Consider the difference between a single-cylinder and a three-cylinder engine. Both use a four-stroke engine (intake, compression, power, exhaust). With a single-cylinder engine, you only get one "power" cycle for every four-cylinder stroke, resulting in rather uneven power delivery. A three-stroke engine, on the other hand, produces power in three alternating phases (again separated by 120 degrees), resulting in smoother, more consistent, and efficient power. Figure2:Three-phase 4.2 Advantages of Three Phase System There are numerous reasons why this power is preferable to single-phase power. The single phase power equation is   Figure3: single phase power equation Which is a function that changes over time. In contrast, the three-phase power equation is   Figure4: three-phase power equation Which is a constant function that is independent of time. As a result, the single-phase power is pulsing. This has no effect on low-rated motors, but it causes excessive vibration in higher-rated motors. As a result, three-phase power is preferable for high-tension power loads. A three-phase machine has a 1.5 times higher rating than a single-phase machine of the same size. Because single-phase induction motors have no starting torque, we must provide an auxiliary means of starting, whereas three-phase induction motors are self-starting and do not require any auxiliary means. In the case of a three-phase system, the power factor and efficiency are both higher. Which is a constant function that is independent of time. As a result, the single-phase power is pulsing. This has no effect on low-rated motors, but it causes excessive vibration in higher-rated motors. As a result, three-phase power is preferable for high-tension power loads. A three-phase machine has a 1.5 times higher rating than a single-phase machine of the same size. Because single-phase induction motors have no starting torque, we must provide an auxiliary means of starting, whereas three-phase induction motors are self-starting and do not require any auxiliary means. In the case of a three-phase system, the power factor and efficiency are both higher.   4.3 Disadvantages of 3-phase Power The most significant disadvantage of a three-phase connection is that it cannot handle the overload. As a result, it may cause damage to the equipment, increasing the likelihood of costly repairs. This is due to the high cost of individual components. Because the unit voltage is so high, a three-phase power connection necessitates a significant investment in insulation. Insulation varies with voltage, and wire size is determined by power distribution.   Ⅴ Why We Need 3-phase Power？ The ability to deliver ever-increasing amounts of power is especially important as data centers and server rooms become denser. More powerful computing systems are being crammed into the same spaces that once housed servers that used a fraction of the electrical power that today's computers and networks require. Not long ago, a single IT rack of ten servers would consume a total of five kilowatts (kW). Today, that same rack may house dozens of servers, each drawing 20 or 30 kW. At those levels, efficiency is important, as even a small percentage improvement in power consumption will result in significant dollar savings over time. Another issue is wiring. Take a look at a 15 kW rack. Using single-phase power at 120 volts AC (VAC), it takes 125 amps to power the rack, which would necessitate a wire almost one-quarter inch in diameter (AWG 4) — too thick to work with easily, let alone affordably. Because three-phase is more efficient, it can deliver the same amount of power (and more) while using less wiring. To support the same 15 kW rack with 3-phase power, three wires capable of supplying 42 amps (AWG 10) are required, each less than one-tenth of an inch in diameter.   Ⅵ What Are the Differences Between Single-Phase Power and Three-Phase Power? The following are the key distinctions between a single-phase and three-phase connection. Ⅶ FAQ 1. How is 3phase power generated? Electric power is generated as three phase alternating current (AC) by turning mechanical turbines from the forces of water, steam, or other means in order to turn generators, thereby, converting the mechanical energy into electric energy. In the US, generators turn at 60 revolutions per second or at 60 hertz (Hz). 2. Why does three phase not need a neutral? A neutral wire allows the three phase system to use a higher voltage while still supporting lower voltage single phase appliances. In high voltage distribution situations it is common not to have a neutral wire as the loads can simply be connected between phases (phase-phase connection). 3. How many wires does 3 phase have? four wires Three-phase has four wires: three actives (called phases) and one neutral. The neutral wire is earthed at the switchboard. 4. How do you make 3 phase voltage? In a 3 phase system, there are three equal voltages or EMFs of the same frequency having a phase difference of 120 degrees. These voltages can be produced by a three-phase AC generator having three identical windings displaced apart from each other by 120 degrees electrical. 5. Does three-phase need a ground? Does the National Electrical Code (NEC) require a 480-volt (V), three-phase, 3-wire, delta-connected system to be grounded? No, it is optional. This article examines the NEC's electrical-system grounding provision. 6. What is the symbol for 3 phase? A three-phase system may be arranged in delta (∆) or star (Y) (also denoted as wye in some areas). 7.Is 240V single phase or 3 phase? 240V power is used in the US and parts of the world. In the US 120 / 240V 1 Phase 3 Wire is the standard for homes and 240V 3 Phase Open Delta is the standard for small buildings with large loads. In parts of the world 240V Single Phase 2 Wire is the standard for homes. 8. What is the value of 3 phase voltage? 3 phase system is expressed with line voltages. The line votage is 440 volt. Also the voltage between any one phase and neutral for a 3 phase system is 240 volts. 9. What is single-phase power used for? Single-Phase Power generates electricity to residential homes and domestic supplies, since most appliances require only a small amount of power to function, including fans, heaters, television, refrigerator, and lights. 10. Why does single phase have 2 wires? Two hot wires and one neutral wire provide the power. Each hot wire provides 120 volts of electricity. The neutral is tapped off from the transformer. A two-phase circuit probably exists because most water heaters, stoves and clothes dryers require 240 volts to operate. 11. Can we use 2 AC in single phase? You can, yes. The main MCB has a current rating of at least 25 ampere. If you use 1.5 ac, it has max load current of 7 to 8 amperes for a single ac, and the MCB size is to be selected. 12.Is 240 volt single-phase? Single Phase 120/240 It may also be called Split Phase 240. This configuration consists of 2 voltage legs that are 180 degrees apart. The voltage between the two legs (called phase to phase or line to line) is 240V and the phase to neutral voltage is 120V.  

Ⅰ IntroductionA motion sensor is a kind of security system. And the linchpin of your security system is a motion sensor (or motion detector) as it detects when someone is in your home who should not be there. A motion sensor detects movement in an area with one or more technologies.When a sensor detects motion, it sends a signal to the control panel of your security system, which is connected to your monitoring center. This notifies you and the monitoring center that there is a potential threat in your home.CatalogⅠ IntroductionⅡ Motion Sensor Related Video:Ⅲ What is a Motion Sensor?Ⅳ Types of Motion SensorsⅤ How do Active Ultrasonic Sensors and Passive Infrared (PIR) Work?5.1 Active Ultrasonic Sensors5.2 PIR SensorsⅥ How to Install a Motion Sensor?Ⅶ Other Uses for Motion SensorsⅧ FAQ Ⅱ Motion Sensor Related Video:How PIR Sensor Works and How To Use It with ArduinoMotion Sensor Video Description：In this Arduino Tutorial we will learn how a PIR Sensor works and how to use it with the Arduino Board for detecting motion. Ⅲ What is a Motion Sensor?A motion sensor (or motion detector) is a genre of electronic device that detects and calculates movement. We can often find motion sensors in the home and business security systems,  as well as in phones, paper towel dispensers, game consoles, and virtual reality systems. Unlike many other types of sensors, motion sensors can not be handled and isolated as they are in embedded systems comprised of three major components: a sensor unit, an embedded computer, and hardware (or the mechanical component). Because motion sensors can be customized to perform highly specific functions, these three parts vary in size and configuration. Motion sensors, for example, can be used to activate floodlights, sound audible alarms, activate switches, and even alert the police. Figure1: Motion SensorⅣ Types of Motion SensorsActive Ultrasonic SensorsActive sensors have a transmitter as well as a receiver. This sensor detects motion by measuring changes in the amount of sound or radiation that is reflected back into the receiver. Passive infrared (PIR)A passive infrared sensor detects body heat (infrared energy) by monitoring temperature changes. This is the most common type of motion sensor found in home security systems. Figure2:Passive infrared (PIR) Microwave (MW)This type of sensor emits microwave pulses and detects reflections from moving objects. 1 They have a larger coverage area than infrared sensors, but they are more expensive and susceptible to electrical interference. Figure3:Microwave (MW) Dual technology motion sensorsThis type of sensor emits microwave pulses and detects reflections from moving objects. 1 They have a larger coverage area than infrared sensors, but they are more expensive and susceptible to electrical interference. Figure4: Dual technology motion sensorsEach sensor type operates in a different part of the electromagnetic spectrum (ranging from passive to active). Dual technology motion sensors are less likely to cause false alarms than other types because both sensors must trip to sound an alarm. This is not to say that they never cause false alarms. Less common types of motion detectorsTomographic motion sensors are composed of several nodes. The nodes connect to form a mesh network. When the link between two nodes is broken, these sensors detect the presence of a person or object.Vibration motion sensors detect people and objects by detecting small vibrations caused by movements such as footsteps. Ⅴ How do Active Ultrasonic Sensors and Passive Infrared (PIR) Work?The two most common motion sensor technologies are active ultrasonic sensors and passive infrared sensors, both of which are well-known for their accuracy and dependability.5.1 Active Ultrasonic SensorsActive ultrasonic sensors produce ultrasonic sound waves that are higher in frequency than the human hearing range. These waves are bouncing off nearby objects and returning to the motion sensor. A transducer within the sensor serves as a signal waypoint, sending the pulse and receiving the echo. The sensor calculates the distance between itself and the target by measuring the time between signal transmission and reception. Most motion sensors allow you to adjust the sensitivity, which means it won't trigger if the distance between the sensor and the object is too great. If the received signal falls within the specified parameters, the motion sensor will activate, alerting you that someone or something is close to the sensor.Motion sensors installed at entry points such as windows and doors can be programmed to sound a burglar alarm. Door and window sensors are specifically designed to detect an intruder, so you should not experience false alarms or excessive notifications.Ultrasonic sensors are capable of detecting objects regardless of color, surface type, or material type (i.e., metallic vs. non-metallic). They can detect translucent objects as well, though this is typically reserved for industrial applications.Figure5:Active ultrasonic sensors 5.2 PIR SensorsPIR sensors are more complicated than active ultrasonic sensors, but the results are the same.Walls, floors, stairwells, windows, cars, dogs, trees, people—you name it—emit heat. Temperature can be detected using infrared waves. Infrared motion sensors detect the presence of a person or object by measuring the temperature change in a specific area. 5.3 Example of PIR SensorsTo demonstrate how this works, we'll use a motion detection camera, though any PIR motion sensor will do.A PIR camera contains two sensors. When no one is present, the PIR camera detects ambient IR emitted by background objects such as walls and doors. When a person (or animal, object, etc.) moves in front of the camera, the first sensor detects their heat signature, causing the camera to activate, triggering your alarm, and sending you an alert. If the object moves out of the camera's field of view, the second sensor will activate, noting the sudden drop in temperature.These temperature changes are used by a PIR motion sensor to detect the presence of a person or object. PIR sensors, like active ultrasonic sensors, can be configured to ignore small changes in IR, allowing you to walk around your home or business without setting off alarms all day and night. Ⅵ How to Install a Motion Sensor?Typical motion sensors have a range of up to 80 feet, which means that a single sensor will most likely not cover a long hallway or an open workspace. You can have your security system installed by a security company such as Bay Alarm. Our installers will examine the layout of your space to determine the best location for motion sensors. Our goal, as with security cameras, fire alarms, and burglar alarm installations, is to make your home or business as secure as possible, with devices and components strategically placed.After the sensors have been installed, a security agent will integrate them with your burglar alarm system. Using one of two apps: SureHome by Bay Alarm or Bay Alarm Access, you'll have quick access to your entire security system from your phone.If you decide to do your own security, make sure to follow the instructions that come with the sensor. Here are some pointers for installing motion detectors in your home or business: Step1:Take your motion detector out of the box.Your motion sensor kit should include instructions as well as mounting hardware. If your device has separate batteries, insert them into your motion sensor now. Step2:TDecide on a locationCorners are ideal because they allow you to position infrared sensors to cover the most ground. Most motion sensor designs have angled edges with screw holes to fit neatly into a room's corner.Mount your motion detector high on the wall to get the best coverage—but avoid putting it over a large piece of furniture, like a bookshelf or entertainment center, because it will limit the passive infrared energy range.Mount your motion sensor opposite the main entrance—this applies in every room or hallway where you place these sensors so they can detect intruders right away. Step3:Mount the sensorBecause passive infrared sensors are lightweight, you won't need drywall anchors or studs. A standard screwdriver will suffice, but an electric screwdriver or drill will expedite the process.Most motion detectors include a mounting bracket that detaches from the main body of the device, allowing you to screw it into the wall first, then clip the motion sensor back in. This also makes removing the motion detector from the wall during maintenance easier. Other infrared sensors may necessitate a complete disassembly before mounting. Step3: Connect your sensor to your systemConnect your motion sensor to your system according to the manufacturer's instructions. Most DIY systems will walk you through this process, frequently using the main keypad or a mobile app to configure and adjust your motion detectors.TIPS: Z-Wave-enabled smart motion sensors connect to your phone for easy access and notifications. Whether you're just getting started with your smart home build or you already have dozens of connected devices, Z-Wave-enabled motion sensors are a worthwhile addition. Step4: Adjust your motion detection settingsWhen you arm your system, most motion detectors have three main settings:In instant mode, any movement sets off an alarm.In entry delay mode, the sensor operates on a delay; even if it detects motion, you have approximately 30–60 seconds to disarm the system before an alarm is triggered.Interior follow-up mode operates on an entry delay, but only when the door contact triggers first—it sounds an instant alarm if it detects motion in the home without the door contact triggering. Step6: Maintain your motion detectorDust and debris can accumulate on the screen of your motion sensor over time, interfering with the infrared energy and making it less effective at motion detection. Use a dry or slightly damp microfiber cloth to clean it at least once every couple of months.If you decide to paint a wall near your motion sensor, make sure to first remove the device. If paint gets on a passive infrared motion sensor, it must be replaced. Additional tips for installing motion sensorsTake into account the size of your pets.Overhangs reduce range.Do not obstruct the infrared.Not all motion sensing light switches are created equal. Ⅶ Other Uses for Motion SensorsMotion sensors are useful for more than just home security. Many industrial fields use them on assembly lines to count the number of products and to shut down dangerous equipment if someone gets too close.Here are a few other uses for motion sensorsTo automate the opening and closing of doorsTo activate and deactivate automatic water faucets and toiletsWhen a person enters a room, lights are turned on.ATM display controlAt ticket vending machinesFor certain parking meter Ⅷ FAQ1. Which motion sensor is best?Best Motion SensorsPhilips. Hue Smart Motion Sensor. A solid choice if you are looking for a motion sensor for indoor use that's also intuitive. ...First Alert. Motion Sensing Light Socket. ...SadoTech. Wireless PIR. ...Chamberlain. Wireless Motion Sensor. ...1byone. Safety Driveway Patrol.2. Are motion sensors effective?Motion sensors are proven to be effective at leading to apprehensions. ... Motion sensors can be more cost-effective for rooms with many windows that would require several sensors to protect. A motion detector can alert you immediately if there is movement is detected.3. What can set off a motion detector?What can set off a motion detector? Moveable objects such as balloons, curtains, decorations, and pets can set off motion detectors. How to prevent this: Consider positioning motion sensors above waist level so pets can move around freely, and away from curtains and other items that may move or drift.4. Do motion detectors work in the dark?The short answer is yes. Motion sensors do work in complete darkness, as none of the motion sensors mentioned above are reliant on using images to detect motion. Instead of images, PIR motion sensors detect changes in the level of received infrared. Likewise, ultrasonic motion sensors also do not require images.5. How long do motion sensors last?On average, a motion detector light will stay on for up to 20 minutes. That amount of time is extended each time a sensor detects fresh movement, so it is possible for a motion detector light to stay on for much longer than 20 minutes at a time.6. Does motion sensor have camera?Most smart security cameras are motion sensor cameras. This means that they have a smart sensor built-in – and that's the key to your smart camera always being ready to record when something happens.7. What is the difference between PIR and motion sensor?As the name implies, motion sensors detect moving objects outside or even inside your home. They are often tied to lights, alarms, security cameras, and most recently, smart doorbells. ... PIR or Passive Infrared motion sensors are designed to reliably detect people, large pets & other large warm moving objects.