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The diode and the negative end of the power supply are connected in series to monitor the current, and the fixed range digital multimeter (DMM) is used to detect the current. This simple design example can realize the current monitoring from a number of μA to 100mA in a single range. This design example has proved to be very useful and simple. Only 3 to 4 modules are needed to monitor the current from the μA over to 100mA in a single range.   Home Energy Monitor Project: Current   As defined by the diode formula IF≅I0 × exp (eVF/kT), the voltage on the diode increases with the logarithmic current flowing through it. Where IF is a forward current, IO is a reverse saturation current, the charge is (1.602 × 10 ~ (-19) C) V _ F is a forward voltage T is the temperature (K), k is the Boltzmann constant (1.380 × 10 ~ (-23) J/K). Depending on the purpose, the following formulas can be extracted: VF∝logIF（temperature fixed）       Catalog   I Shunt Diode II Adding Extra Diodes III. LTspice IV Conclusion FAQ     I Shunt Diode Now let ' s look at a diode with a measuring instrument . When the current is low , it indicates the milliampere ( mA ) level current that flows through the meter rather than the diode; while in a large current it displays the voltage on the diode, and the logarithm of the current thus derived ( imagining the diode as a self-adjusting shunt ) . Therefore the bottom of the meter scale is therefore quite linear and the top has enough logarithmic properties and the middle is a transition phase , so the entire range is very useful. As shown in Fig.1, using a Schottky rectifier, a 100μA/1.7kΩ meter and an appropriate series resistor can monitor the current from 10 μA to over 100mA within a single range, and the indicated speed is limited to the pendulum speed of the meter. Fig. 1 Schottky rectifier, 100 μ A / 1.7 kΩ meter and suitable series resistance This simple circuit often has more problems than the number of components, in addition to the high-precision calibration process, the circuit also has two main drawbacks: series voltage drop and temperature stability. The diode voltage drop is as high as 400mV, so it is best to use a new or charged battery when monitoring, otherwise your measured components may show that the battery is low. Or treat the circuit as a convenient low-voltage test circuit that might add a short-circuit switch.   II Adding Extra Diodes At the bottom of the scale, almost all current flows through the instrument, which is limited by the machine and magnetic temperature coefficients, and the measured temperature coefficient is very low. But at large currents, a voltage drop can be seen on the diode, which will drop at a rate of about 2mV/K, as predicted by the diode formula. This not only affects the slope of low of logarithm, but also affects the transition point from linear to logarithmic. In addition, the meter windings account for a large part of the total series resistance, and the TCR of copper at room temperature is 3930 ppm/kg. Fig.2 shows the relation curves of deviation and current of 1N5817 at 0℃, 25℃ and 50℃. These curves take into account the TCR of the measuring circuit and the temperature coefficient of the diode, but ignore the self-heating effect of the latter, but there is no problem at relatively stable temperature. Fig. 2 Deviation and current curve Self-heating mainly exists in D1 will have no impact on current. Suppose the current flowing through is 100mA, the voltage drop D1 is 400mV—that's 40mW. According to the manual, the basic thermal resistance of a D0-41 1N5815 with a slightly longer pin and a large amount of radiating copper is 50 K/W. When these data are taken into account, the temperature rise of the node is only 2℃ at 100mA, which is equivalent to the reduction of VF by about 4mV, or the error of about 1% at full scale. Try to keep the diode to a short pin and high thermal quality, noting that there may be high transient currents during conduction, as these can lead to errors until the temperature of the node cools again. Fig. 3 An improved version of the offset temperature coefficient Fig. 4 The bias and current curve after adding a diode Fig. 4 shows the curve of the circuit. Note that most of the curve is now in logarithmic form, and that extra diode effectively suppresses the initial linear region. However, the selection of this diode is critical because the forward voltage of D2 should be slightly lower than that of D1, but other features should match.   III LTspice D1 using 10MQ060N and D2 using BAT54—this is the first pair of components emulated. Both are cheap, modeled by LTspice and are therefore recommended components. A pair of 10MQ060N works almost consistently (but a pair of BAT54 is inconsistent). In most of the time, this group combines with other components showing worse temperature variations and strange indications, so it is necessary to  model the circuit before building it. If the sensitivity and resistance of the instrument are appropriate, R1 can be omitted. On the same thermal properties, the D1 and D2 can track mutual temperature changes. Silicon P-N junction diodes generally have a very straight (log IF) / VF relation, while Schottky's straight line is not. This is because their structures have higher series resistance, are more closed to linear than logarithmic at very low currents, and have protection loops to control the potential gradient of P-N diodes that are parallel to Schottky nodes. Therefore, in practice, the exact logarithmic law will change with the current and the type of component. Although a used diode may be fine for the first pair, due to the inevitable inaccuracy of the circuit, the double diode design still needs to be carefully selected. Schottky diodes can provide more reference resources. 100 μ A /1700 Ω indicators, which are very common, very tightly connected, very useful, and their linear and structure are well consistent with units, just match the 35mm × 14mm aperture, so select them. The calibration points used in Fig.5 are generated by arranging a series of combinations of monitors, batteries, fixed and variable resistors, and the DMM series. Existing test scales are marked at the appropriate points and then removed and scanned, which are used as templates for the final layout.  The simulation results are used to generate the reference point in Fig.5 (left), and the results well reflect the actual operation, although the multimeter is poor. These scales can save time, but are not as accurate as they are newly made (obviously these measuring structures need different scales), and R1 can be calibrated slightly (the instrument is set at ±20%). Both scales consider the non-linearity of the instrument structure. Fig.5 The calibration point (right) of the monitor, battery, fixed and variable resistor, and DMM combination IV Conclusion Whatever, now that these circuits are embedded in most of my development projects and even in production testing devices, they are effective in finding a variety of faults and problems, from power lines short-circuiting to the pull-up pins of miscoding. In order to facilitate the monitoring of the current, it is necessary to connect the appropriate diode with the negative end of the power supply and monitor its forward voltage drop. After some simple calibration, you can monitor the supply current in full sync with the other parameters you want to detect.   FAQ   1. What is a shunt diode? In electronics, a shunt is a device that creates a low-resistance path for electric current, to allow it to pass around another point in the circuit. ... The origin of the term is in the verb 'to shunt' meaning to turn away or follow a different path.   2. What is shunt and its uses? shunt is a device which allows electric current to pass around another point in the circuit by creating a low resistance path. A shunt (aka a current shunt resistor or an ammeter shunt) is a high precision resistor which can be used to measure the current flowing through a circuit.   3. How does a shunt diode work? The shunt regulator operates by maintaining a constant voltage across its terminals and it takes up the surplus current to maintain the voltage across the load. One of the most common examples of the shunt regulator is the simple Zener diode circuit where the Zener diode acts as the shunt element.   4. What are the disadvantages of shunts? a. It has poor efficiency for large load currents. b. It has high output impedance. c. The output DC voltage is not absolutely constant because both VBB and VZ voltages decrease with increase in room temperature.   5. Where is shunt used? The shunt is used in the galvanometer for measuring the large current. It is connected in parallel to the circuit of the galvanometer. The galvanometer is the current sensing devices. The direction of flow of current inside the circuit is determined by the pointer of the galvanometer.   6. Why shunt is always connected in parallel? A shunt resistance should be connected in parallel to the galvanometer so as to keep its resistance low. Such low resistance galvanometer ( ammeter) is used in series with the circuit to measure the strength of current through the circuit.   7.How is shunt current calculated? How to Calculate a Shunt: a. Write down the Ohm's law expression of "V = I * R" where "V" is the voltage drop across shunt resistor, "I" is the current flowing through shunt and "R" is the shunt resistance. b. Substitute value of voltage "V" and current "I" in the Ohm's law expression.   8. What size shunt do I need for battery monitor? A 100 amp shunt would be plenty if you are only using 12v devices like water pump, furnace blower and lights. We have an inverter and pass up to 200 amps sometimes. The shunt that came with our monitor is good for 500 amps. It doesn't hurt to have a shunt larger than you need.   9. Why shunt is used in galvanometer? Since galvanometer is a very sensitive instrument that it can not measure the heavy currents . to do so A shunt is connected with parallel with galvanometer to convert it into ammeter. ... so after that it can measure heavy currents in the circuit.   10. Is a shunt a resistor? A shunt is a low-ohm resistor that can be used to measure current. Shunts are always employed when the measured current exceeds the range of the measuring device.

Warm hint: The word in this article is about 1000 words and reading time is about 5 minutes     This article introduces you some basic and simple rectifiers and their waveforms and working principle and more.   Catalog I. Introduction 1.1 Composition of DC Stabilized Power Supply 1.2 Basic Concepts II. Detail & Analysis 2.1 Half-Wave Rectifier 2.2 Full-Wave Rectifier 2.3 Bridge Rectifier 2.4 Capacitor Filter 2.5 Inductor Filter FAQ   I. Introduction   1.1 Composition of DC Stabilized Power Supply FIG.1   2. Basic Concepts   AC voltage (current): both amplitude and direction change periodically with time. FIG.2 Sinusoidal Voltage/Current Waveform (AC): alternating voltage/current whose amplitude and direction both change sinusoidally and periodically over time. It is often called AC for short.   Effective value: the direct voltage/current thermally equivalent to the alternating voltage/current is called the effective value of the AC (voltage or current).   Peak value: the maximum instantaneous value of AC (voltage or current).   Frequency: the number of times that AC (voltage or current) changes periodically every second.   Direct voltage/current: voltage/current whose value and direction do not change with time. In fact, the direction can be guaranteed not to change over time, but it is impossible for the value to act the same way all the time. So the alternating voltage/current whose direction is always the same and the numerical value changes over time can be explained as a superposition of DC (voltage or current) and AC (voltage or current) whose amplitude and direction change with time. II. Detail & Analysis   2.1 Half-Wave Rectifier The circuit diagram and the waveforms of half-wave rectifier are shown as the following figures. FIG.3 Average value: FIG.4 Effective value: Turns ratio: According to this, the required output voltage can be obtained by selecting the appropriate N1 and N2.   2.2 Full-Wave Rectifier The following figures are the circuit diagram and the waveform of full-wave rectifier. FIG.5 FIG.6 Average value: Effective value: Transformer: The number of turns of the primary winding is N1, and the number of turns of the secondary winding is N2a=N2b. Turns ratio: According to this, the required output voltage can be obtained by selecting the appropriate N1, N2a and N2b.   2.3 Bridge Rectifier The following figures are the circuit diagram and the waveform of bridge rectifier. FIG.7 FIG.8 Average value: Effective value: Transformer: The number of turns of the primary winding is N1, and the number of turns of the secondary winding is N2. Turns ratio: According to this, the required output voltage can be obtained by selecting the appropriate N1 and N2.   2.4 Capacitor Filter The following figures are the circuit diagram and the waveform of capacitor filter. FIG.9 Filtering principles: a~b: u2=uc=u0, the capacitor C is charged in a sine wave; b~c: u2≈uc = u0, the capacitor C discharges in an exponential curve, but the sinusoidal waves of u2 basically coincide. c~d: u2＜uc=u0, the capacitor C continues to discharge exponentially, and u2 to drop in a sine wave. FIG.10 The effects of RL and C on filtering are shown in the following figure. FIG.11 （1）Basic knowledge of capacitors   Definition:   Basic equations:  Energy equation:  FIG.12 （2）Charging the capacitor Where  It is a time constant, and the initial values of current is  FIG.13 （3）Discharging the capacitor Where It is a time constant, and the initial values of current is FIG.14 （4）Output voltage   After the filtered voltage waveform is linearized, the following approximate waveform is obtained: FIG.15 Based on the relationship of similar triangles, there is And  So we have When There is  FIG.16 Rectifier diode: The current and the conduction angle of the rectifier diode in the capacitor filter circuit are shown in the following figure: FIG.17 Where iD is the current of the rectifier diode when the current is switched on, and io is the current in the load.   2.5 Inductor Filter In heavy current load, if a filter capacitor is used, the capacitance of it and the inrush current of the rectifier both will be very large. But if an industrial-frequency inductor is in series with it for filtering after the rectification, then we can solve these problems very well. The following figure is the circuit diagram of the inductor filter. FIG.18 From the energy point of view, the effects of the inductive filter and the capacitive filter are the same. Therefore, the volt-ampere characteristics of the inductive filter is similar to that of the capacitive filter, see the figure below. FIG.19 The quantitative analysis of inductive filter is more complex, so we should do it with the help of the previous analyzed results for the capacitive filter. If  then we have When the inductor filter is used, the waveform of the terminal voltage and current of the inductor and the conduction angle of the rectifier diode are shown in the following figure. Because the rectifier diode is connected in series with an inductor, the conduction angle of it can reach 180°. Therefore, in situations where harmonics are not demanding, we can use inductive filter to meet PFC (Power Factor Correction) requirements. FIG.20 （1）Basic concepts of inductor FIG.21 Definition:  Basic equations: Energy equation: （2）When inductor stores energy   After the switch is closed, here we have According to the initial conditions, the solution is Where It is a time constant, and the initial voltage is FIG.22 （3）When inductor releases energy FIG.23 After the switch is closed, here we have According to the initial conditions, here we have: Where It is a time constant, and the initial voltage is FIG.24 How Amplifiers Work: Rectifiers and Filter Capacitors   FAQ   1. What are the types of rectifiers? The Different Types of Rectifiers: a. Single Phase & Three Phase Rectifiers. b. Half Wave & Full Wave Rectifiers. c. Bridge Rectifiers. d. Uncontrolled & Controlled Rectifiers.   2. What is Rectifier used for? A rectifier is an electrical device that converts alternating current (AC), which periodically reverses direction, to direct current (DC).   3. What is an example of rectifier? Thyristors are commonly used in place of diodes to create a circuit that can regulate the output voltage. Many devices that provide direct current actually generate three-phase AC. For example, an automobile alternator contains six diodes, which function as a full-wave rectifier for battery charging.   4. Is Zener diode a rectifier? A Zener diode is a special type of rectifying diode that can handle breakdown due to reverse breakdown voltage without failing completely. Here we will discuss the concept of using diodes to regulate voltage drop and how the Zener diode operates in reverse-bias mode to regulate voltage in a circuit.   5. What is the working principle of rectifier? Principle: A junction diode offers a low resistance to current in one direction(when forward biased) and a high resistance in the other direction(when reverse biased). Thus, the diode acts as a rectifier.   6. Why zener diode is not used in Rectifier? No, we don't prefer to use a Zener Diode in a rectifier circuit because for a rectifier circuit a high maximum peak inverse voltage is required. Unlike the normal p-n junction diode, a Zener diode has a low peak inverse voltage. This is an undesirable property for the rectifier circuit.   7. What are the signs of a bad Rectifier? You'll note signs right away like poor starts, fluctuating meter readings, and dimmed headlights. around 13 volts, the bike will start to drain the battery. When this happens, it's only a matter of time before the engine stops completely.   8. What causes a rectifier to fail? Ground connections are important for good voltage, and if there is faulty voltage, the regulator rectifier can run hot. Bad grounding, corroded battery connection and poor or loose battery connections will cause faulty voltage.   9. Will a bad rectifier cause no spark? A bad regulator/ rectifier will result in a dead battery, and once the battery is competely dead you will not get a spark.   10. What is the difference between diode and rectifier? A diode is a switching device, while a rectifier is generally used for the conversion of AC voltage to DC voltage. ... A diode allows the flow of current only when it is forward biased. The diode blocks the reverse flow of current. A rectifier, on the other hand, consists of a transformer, a diode, and a filter circuit.   You May Also Like: Transformers Basics: Construction, Types, Materials and Design Characteristics and Functions of Diodes Switched Mode Power Supply Tutorial: Principles & Functions of SMPS Circuits

  After 20 years, your life may be like this:The electronic skin on your pulse can monitor your heart rate and blood sugar at any time to realize intelligent pulse detection;The electronic skin on your throat can "voice" for the deaf and mute by feeling the pressure changes produced by the movement of the throat muscles;Your whole body may become a network center, and the sensors in your body will connect with the outside world...All this seems very far away, but these technologies are quietly gestating, and are very likely to become disruptors of new technologies.Flexible Electronics: The Future of TECHNow is the era of smart phones, but the current smart electronic products are still rigid electronic devices. In the future, mankind is about to enter a new era, the era of flexible electronics. Flexible electronic devices that are as soft as human skin will be the next development trend of the electronics industry, and may even subvert human life. Catalog I What is Flexible electronics?II Applications of flexible electronics2.1 Flexible electronic display2.2 Thin film solar panels2.3 RFID2.4 Electronic skinIII ConclusionFAQ  I What is Flexible electronics? The concept of flexible electronics started in the 1980s, when people tried to replace inorganic semiconductors such as silicon with organic semiconductors, so that organic electronic devices have flexible characteristics.Flexible electronic technology is a brand-new electronic technology revolution. It is an emerging electronic technology that makes organic and inorganic materials electronic devices on flexible, malleable plastic or thin metal substrates. It has a wide range of fields in information, energy, medical treatment, and national defense.  Applications of flexible electronics In addition to integrating electronic circuits, functional materials, micro-nano manufacturing and other fields of technology, flexible electronic technology also spans industries such as semiconductors, packaging, testing, materials, chemicals, printed circuits, and display panels. Not only that, it can also help the transformation and upgrading of traditional industries, such as plastics, printing, chemicals, and metal materials.By improving its performance and industrial added value, flexible electronics will frequently appear in human life, bringing revolutionary changes to the industrial structure and future life. As technology upgrades, flexible electronics materials research and development and rich application products have emerged.II Applications of flexible electronicsWith the development of flexible electronic technology, various electronic products have emerged. Just as microelectronics technology provides a technology platform for large-scale integrated circuits and computer chip technologies, flexible electronic technology provides a brand-new technological platform for the research and development of new products. 2.1 Flexible electronic displayThe flexible electronic display is a brand-new product developed on the flexible electronic technology platform. Unlike traditional flat-panel displays, such displays can be repeatedly bent and folded, thus bringing great convenience to our lives.For example, all visual materials, including books, newspapers, magazines, and video files, can be presented on this display and can be viewed anytime, anywhere. Although current popular MP4 players and personal digital assistants (PDAs) can meet such use needs, the display screen cannot be bent and folded, and can only be read and viewed in a small screen area. And video, visual effects are greatly constrained. In contrast, flexible electronic displays have unparalleled advantages. They are like newspapers. When they are needed, they are unfolded. When they are used, they are curled or even folded. This guarantees the convenience of portability while giving full consideration to the visual effects.Flexible electronic displaySamples of flexible electronic displays have been successfully developed and it is believed that it will be a long way from entering the market. It is worth mentioning that flexible electronic displays use more lightweight organic materials instead of inorganic materials, so their weight is lighter than traditional displays, and this feature helps to improve their portability. In addition, the use of high molecular organic materials offers possibilities for reducing costs. In addition, the flexible electronic display has the characteristics of a thin thickness, and its thickness can be much smaller than that of the popular liquid crystal display. Therefore, another name of the flexible electronic display is a paper-like electronic display.2.2 Thin film solar panelsThin film solar panel is another specific application of flexible electronics technology. In today's world, energy has become a topic of global concern. China not only faces energy shortages but also faces environmental pollution. As a clean energy source, solar energy can effectively alleviate the contradiction of energy shortage under the premise of zero environmental pollution.As the most common way to use solar energy, solar panels can cover a large area at the lowest cost to effectively use solar energy. At present, thin film amorphous Sili-Con solar panels have been successfully developed and marketed. Thin film solar panel Thin-film solar panels based on flexible electronic technology can meet high-power generation needs, such as the use of thin-film solar panels in solar power plants in sunny desert areas.In addition, it can also make full use of its flexible and lightweight features to integrate it into clothing. Putting on such clothes to walk or exercise in the sun, the power of small appliances (such as MP3 players and laptops) that are carried around can be supplied by the thin-film solar panels on the clothes, thus achieving the purpose of saving and environmental protection.2.3 RFIDRadio frequency identification (RFID) technology can be used to complete information input and processing, fast and convenient operation, and rapid development without manual contact, and is widely used in production, logistics, transportation, medical, food, security and other fields. RFID systems usually consist of transponders and readers.The electronic tag is one of many forms of transponder, and can be understood as a transponder with a thin film structure, which has the characteristics of convenient use, small size, thin and light, and can be embedded in the product. More and more electronic tags will be used in future RFID systems.Flexible Electronics in RFIDIn this response to Covid-19, flexible electronic technology has played a huge role in body temperature measurement.Group body temperature measurement has problems such as huge number of monitoring people, cumbersome temperature measurement work, and difficulty in continuous temperature recording. Wearable temperature measuring stickers made by introducing flexible electronic technology can record and analyze the body temperature data of the target population. In this way, potential threats can be discovered and eliminated through long-term monitoring, thereby helping management departments to achieve personnel management monitoring.2.4 Electronic skinAnother important application of flexible electronics is electronic skin. Electronic skin, also called skin-like electrons, is basically characterized in that various electronic components are integrated on a flexible substrate to form a skin-like circuit board, which has high flexibility and elasticity like skin and can be used in many other applications. electrical equipment.It can be said that the potential of flexible electronic skin is great. With the popularization of technologies such as smart medical care, virtual reality, and artificial intelligence, the demand for wearable devices has surged, and flexible electronic skin is a perfect combination of wearable devices. Think about an electronic component installed on the body and used as a skin, isn't it sci-fi?Electronic skinIII Conclusion Folding computers, folding mobile phones, and wearable digital products are in the ascendant. With the development of science and technology, flexible electronic devices have received more and more attention from the society. Such devices can still work under bending, folding, twisting, compression or stretching conditions. In the future, flexible electronic equipment will have a very broad development space in the fields of energy, medical, information and communication.Pieces of work brought by flexible electronics are interpreting the integration of innovation and tradition in the era of the Internet of Everything, and the era of science and technology connecting everything is approaching.You can boldly imagine that in 20 years, your life might be like this:In the morning, the flexible electronic skin watch on your body wakes you up and reports the quality of your sleep. Put on your glasses, and the day’s schedule has been displayed for you on the transparent screen. After washing, the robot has prepared breakfast for you and your family; After going out, the smart watch on your wrist shows that the air quality is excellent; the smart assistant called "Flying" for you and has parked outside the house, waiting for you to start your day's itinerary... FAQ 1. Why are electronics flexible?The key advantages of flexible electronics, compared with current silicon technologies, are low-cost manufacturing (e.g. ink-jet printing and roll-to-roll imprinting) and inexpensive flexible substrates (e.g. plastics). ... In principle, flexible electronics is ideal for integration. 2. Where are flexible electronics used?Consumer electronics devices make use of flexible circuits in cameras, personal entertainment devices, calculators, or exercise monitors. Flexible circuits are found in industrial and medical devices where many interconnections are required in a compact package. 3. How could Flexible Electronics benefit the consumer?Among the benefits of flexible electronics (compared to traditional, rigid alternatives) are size, weight, portability, and energy efficiency. Above all, they make previously impossible designs and technologies (such as wearable devices) possible. 4. When was flexible electronics invented?1960s. Flexible electronics have a long history. The first flexible device was made in the 1960s by thinning crystalline silicon solar cells for use in extraterrestrial satellites. Today, smart credit cards carry bendable microchips which are made using stretchable Silicon. 5. What are flexible electronics made of?Flexible Electronics: generally refers to a class of electronic devices built on conformable or stretchable substrates, usually plastic, but also metal foil, paper and flex glass. 6. What are the two major approaches of making flexible electronics?(1) Transfer and bonding of completed circuits to a flexible substrate(2) Fabrication of the circuits directly on the flexible substrate  7. What makes flexible electronic display attractive?One property of flexible electronics which deserves to be highlighted is their robustness. This makes a great difference for applications such as wearables, notebooks and other consumer electronics which traditionally feature glass-based displays or sensors. 8. How flexible electronics are made?Compared with conventional microelectronics, flexible electronics does not require extrinsic packages such as ceramics. Instead, flexible circuits and packages can be manufactured and integrated together using only plastics. ... These layers can then be stacked together to complete the flexible electronic systems. 9. Why are flexible electronics important?Among the benefits of flexible electronics (compared to traditional, rigid alternatives) are size, weight, portability, and energy efficiency. Above all, they make previously impossible designs and technologies (such as wearable devices) possible. 10. Why do we need flexible materials?Not only does flexible packaging use less material than its rigid counterparts, leading to a lower overall packaging cost, it also creates less waste. Fres-co states that flexible packaging formats create 50 percent less waste than rigid ones, while also reducing greenhouse gas emissions and BTU consumption. 

IntroductionThe Raspberry Pi is a small and powerful computer that you can use to learn programming through fun, practical projects. It is designed for encouraging people in computing and creating easier access to computing education. Pi is a microcomputer and its size is like a credit card. Its system is based on Linux and has all functions such as video and audio. With the release of Windows 10 IoT, we will also be able to use the Raspberry Pi on Windows.Raspberry Pi - All You Need To KnowCatalogIntroductionⅠ Who Invented the Raspberry Pi?Ⅱ Different Pi Versions2.1 Early Stage2.2 Pi Model B vs Pi Model B+2.3 Pi 22.4 Pi 2 Model B vs Pi Model B2.5 Pi 3 Model B2.6 Pi 4 Model B vs Pi 3 Model B+2.7 Pi 4 Model B Rev1.2 (8GB RAM Version)Ⅲ What can I do with Raspberry Pi?Ⅳ Raspberry Pi Programming Language4.1 Python4.2 C Language4.3 Java/BlueJ4.4 PERL4.5 ScratchⅤ Guide for Beginners: Use Raspberry Pi to Control LED Lights5.1 Model Selection5.2 Accessories5.3 Electronic Components5.4 System Installation5.5 SSH Login In5.6 Install Node5.7 Light LED5.8 LED Control Script5.9 HTTP ServerⅥ FAQⅠ Who Invented the Raspberry Pi?The Raspberry Pi was developed by the Raspberry Pi Foundation, an British charity. In March 2012, Eben Upton of the University of Cambridge officially launched the world’s smallest desktop computer, also known as a card computer, which has all the basic functions of a computer. This is Raspberry Pi. The purpose of this foundation is to promote the education of computer science and related subjects in schools and make computers interesting. The foundation expects that this computer will continue to be developed and applied to more fields in the world.The early concept of Raspberry Pi in 2006 was based on ATmega644 microcontroller. It is an ARM-based microcomputer motherboard, with SD/MicroSD card as the memory hard disk. There are 1/2/4 USB ports and a 10/100 Ethernet port around the card motherboard (type A does not have a network port), which can be connected keyboard, mouse and network cable, as well as a TV output interface for video analog signals and an HDMI high-definition video output interface. All the above components are integrated on a motherboard that is only slightly larger than a credit card. It has all the basic functions of a PC and only needs to be connected to the TV. And the keyboard can perform many functions such as spreadsheets, word processing, games, high-definition video and so on.The Raspberry Pi is produced through three companies with production licenses Element 14/Premier Farnell, RS Components and Egoman. The Raspberry Pi Foundation provides ARM-based distributions of Debian and Arch Linux for the public to download. It is also planned to provide support for Python as the main programming language, support for programming languages such as Java, BBC BASIC (via RISC OS image or "Brandy Basic" clone of Linux), C and Perl. Ⅱ Different Pi Versions2.1 Early StageIn the early days of the Raspberry Pi, there were two types, model A and model B. The main differences between them.Model A: 1 USB, no wired network interface, power 2.5W, 500mA, 256MB RAM.Model B: 2 USB, support wired network, power 3.5W, 700mA, 512MB RAM. In addition, the Raspberry Pi B model provides a computer board, power supply, keyboard, case or connection, but no RAM.In July and November 2014, the Raspberry Pi launched two models, B+ and A+, respectively. The main difference: Model A has no network interface, so the four USB ports are reduced to one. In addition, compared to Model B, Model A has reduced RAM capacity and has a smaller size. Model A can be said to be a cheap version of Model B, but the new model Model A also supports the same MicroSD card reader as Model B, 40-pin GPI port, Broadcom BCM2385 ARM11 processor, 256MB of memory and HDMI output port.In terms of configuration, model B+ uses the same BCM2835 chip and has 512MB RAM as model B. But compared with the previous generation, the B+ version has lower power consumption and more interfaces. Model B+ has increased the general-purpose input and output pins to 40, and the USB interface has also increased from 2 to 4. In addition, the power consumption of model B+ has been reduced by about 0.5W to 1W. The old SD card slot has been replaced with a more beautiful push-in microSD card slot, and the audio part uses a low-noise power supply. From the appearance point of view, the USB interface has been moved to the side of the motherboard, the composite video has been moved to the position of the 3.5mm audio port, and four independent mounting holes have been added.2.2 Pi Model B vs Pi Model B+In July 2014, the Pi Model B+ was released, still using the BCM2835 processor and the same system software as the previous generation. The RAM is still 512MB. But improvements have been made in the following key points:Figure 1. Raspberry Pi Model B1) More GPIO pins, a total of 40 pins. (The old version is 26 pins)2) 4 USB ports, and the hot swap and overcurrent protection have been improved.3) Use Micro SD slot not the SD.4) Lower power consumption, reducing power consumption by 0.5 to 1W.5) Audio optimization, the audio circuit uses a dedicated low-noise power supply.6) A more concise appearance, the B+ aligns the USB interface with the edge of the circuit board, removes the AV interface, and makes 4 fixing holes on the motherboard.2.3 Pi 2Figure 2. Raspberry Pi 2It is compared to previous generations.1) CPU single thread speed is increased by 1.5 times (up by 1.5x).2) Sunspider running score increased 4 times (4x faster).3) Multi-core video decoding rate based on NEON is increased by 20 times (20x faster).4) The overall multi-threaded CPU score of SysBench is 6 times (6x) that of the old version.2.4 Pi 2 Model B vs Pi Model BFigure 3. Raspberry Pi 2 Model B1) Equipped with a 900MHz quad-core ARM Cortex-A7 CPU, the performance is expected to be 6 times that of the previous B+ version.2) 1GB LPDDR2 SDRAM, twice the previous B+ version.3) Fully compatible with the Pi 1 generation.Since the CPU has been upgraded to the ARM Cortex-A7 series, the Raspberry Pi 2 will support the full range of ARM GNU/Linux distributions, including Ubuntu and even Windows 10.2.5 Pi 3 Model BFigure 4. Pi 3 Model BIn February 2016, the Raspberry Pi 3 Model B was released.1) Equipped with ARM Cortex-A53 1.2GHz 64-bit quad-core ARMv8 CPU.2) Add 802.11b/g/n wireless network card.3) Add low-power Bluetooth 4.1 adapter.4) The maximum drive current is increased to 2.5A.2.6 Pi 4 Model B vs Pi 3 Model B+Figure 5. Pi 4 Model B1) Equipped with Broadcom BCM2711, Quad core Cortex-A72 (ARM v8) 64-bit SoC @ 1.5GHz.2) VideoCore VI GPU, supports H.265 (4Kp60 decode), H.264 (1080p60 decode, 1080p30 encode), OpenGL ES 3.0 graphics.3) 1GB/2GB/4GB LPDDR4 memory.4) Full throughput Gigabit Ethernet (PCI-E channel).5) Support Bluetooth 5.0, BLE.6) Two USB 3.0 and two USB 2.0 ports.7) Dual micro HDMI output, support 4K resolution.8) The microSD storage system adds double data rate support.9) The previous version of the microUSB power supply interface has been changed to a USB Type-C interface in Pi 4 Model B.10) Increase driving current to 3A.2.7 Pi 4 Model B Rev1.2 (8GB RAM Version)On May 28, 2020, the Raspberry Pi Foundation announced the launch of the new Raspberry Pi 4B SKU, which is the 8GB RAM version. In order to make full use of it, Raspberry Pi also developed a dedicated 64-bit operating system based on Debian. In other respects, compared with the previous version, the power supply problem has been improved.Figure 6. Pi 4 Model B Rev1.2TMHW's test on the Pi 4B 8GB version shows that in terms of web performance, 7zip compression, and APP opening speed, 8GB does not even increase but decrease compared to 4GB. In addition, in a 32-bit system, the available RAM is 7.8GB, and a 64-bit system is reduced to 7.6GB. Ⅲ What can I do with Raspberry Pi?Just like any other desktop or portable computer running a Linux system, there are many things you can do with the Raspberry Pi. Of course, it is inevitable that there is a little difference. Ordinary computer motherboards rely on hard drives to store data, but for Raspberry Pi, SD cards are used as "hard drives", and you can also connect an external USB hard drive. Use Raspberry Pi to edit documents, browse the web, play games, etc. That is to say, it has a wide range of uses. So it is also a good choice to make it an excellent multimedia center. For example, the Pi can be used to play video, and it can even be powered through the USB interface of the TV.Figure 7. Raspberry Pi 4Ⅳ Raspberry Pi Programming Language4.1 PythonThe Pi in Raspberry Pi stands for Python. It has become one of the most famous programming languages used for coding. After all, it has been in continuous use for the past 20 years. Python has an easy-to-read syntax, which is very suitable for novices in the field. Now, it is widely used in modern applications, windows and online applications.4.2 C LanguageC is one of the most widely used computing languages in the world. It is widely used to create operating systems and even simple programming languages. As we all know, Raspberry Pi runs on Linux system, in fact, it is also written with C. Therefore, it is easily compatible with all Linux and Unix systems including Pi.4.3 Java/BlueJWhen it was first released, Java was hailed as the first language that allowed programmers to write code for any platform or operating system. Regardless of whether the platform is a windows machine or a Unix machine. You can run the program without rewriting the code. Once the code is compiled, it can be run anywhere. Java runs on the Raspberry Pi, but cannot be developed on it. By 2013, BlueJ was released. Once installed, it can be programmed in Java on the Raspberry Pi.4.4 PERLPERL is a high-level programming language. It can be conveniently used on the Raspberry Pi when building an automated process or analyzing and debugging its output. Perl has a better library and ecosystem. It is the default setting of Raspberry Pi. Through a simple meta-analysis of the quality of existing libraries, PERL can be updated to a better version, because the default library may be incomplete or of low quality.4.5 ScratchScratch is the second programming language that suitable for Raspberry Pi. Because this coding language is included with the Raspberry Pi kit. It is a visual programming tool. With it, you can create animations and games. The latest version allows programmers to control Raspberry Pi's GPIO (General Purpose Input and Output) pins. Ⅴ Guide for Beginners: Use Raspberry Pi to Control LED Lights5.1 Model SelectionRaspberry Pi is a tiny computer integrated on a circuit board. Currently, there are two latest (1) Raspberry Pi 3 Model B(2) Raspberry Pi zero (zero w)Although the latter is cheap, it lacks a lot of interfaces (for example, only one USB port), the CPU and memory are relatively low-capacity, and the accessories are also few. Therefore, it is recommended to buy the third-generation B-type. But zero w can also meet most of the needs.5.2 AccessoriesThe Raspberry Pi itself is just a host. If you want to run it, there must be accessories.(1) Power SupplyA mobile phone charger with a Micro USB interface can be used as a power source, but the output must be 5V voltage and at least 2A current. It’s okay to use a power bank as a power source.Figure 8. Micro USB(2) Micro SD CardThe Raspberry Pi does not have a hard drive, and the Micro SD card is the hard drive. The minimum capacity is 8G, and 16G and 32G cards are recommended.Figure 9. Micro SD(3) DisplayThe Raspberry Pi has HDMI output, and the display must have it. If there is an HDMI to VGA adapter cable, then the VGA monitor will also work. Here I use a 7-inch LCD monitor.Figure 10. LCDHowever, the monitor is only needed when installing the system, and SSH can be used to log in later.(4) Wireless Keyboard and MousePi has built-in Bluetooth, so USB or Bluetooth wireless keyboard and mouse can be used.Figure 11. Wireless Keyboard and MouseJust like the monitor, if the Pi has been installed with the system and only used as a server, the wireless keyboard and mouse are not required.5.3 Electronic ComponentsIn addition to accessories, the following experiment also requires some electronic components.(1) Breadboard (one piece)(2) Electrical Cable (several)Note that the connection cable must be female to male.Figure 12. Electrical Cable (Female)Figure 13. Electrical Cable (Male)In addition, it is best to prepare some cables with male to male.(3) LED Diodes (several)(4) 270Ω Resistors (several)5.4 System InstallationIf the merchant has already installed the system, you can skip this step, otherwise you need to install the operating system.The official operating system is Raspbian, which is a customized version of the Debian system.The official also provides an installer NOOBS. It is recommended to install Raspbian through it, which is relatively simple.Download NOOBS:1) Format the Micro SD card into FAT format (operation guide).2) Unzip NOOBS.zip to the root directory of the Micro SD card.3) Insert the Micro SD into the slot at the bottom of the Raspberry Pi, turn on the power, and start the system.4) Under normal circumstances, follow the prompts on the screen and press Enter all the way to install the system.5.5 SSH Login InAfter installing the system, the Pi can access the Internet (Wifi or network cable). At this time, you need to check its LAN IP address, you can use the following command.    $ sudo ifconfigThen, change the system settings and turn on SSH login (default is forbidden).Then, login the Raspberry Pi from another computer SSH. The following command is executed on another computer in the LAN.    $ ssh pi@192.168.1.5In the above code, 192.168.1.5 is the address of my Raspberry Pi, so you need to replace it with yours. The default user of the Raspberry Pi is pi, and the initial password is raspberry. Under normal circumstances, you can log in to it. Then, you can perform various server operations, such as changing the password.    $ passwdThe following experiments need to add users to the gpio user group.    $ sudo adduser pi gpioThe above code means adding user pi to the gpio user group.5.6 Install NodeIn order to run Node scripts, Raspberry Pi must install Node. You can refer to this.    $ curl -sL https://deb.nodesource.com/setup_8.x | sudo -E bash -    $ sudo apt install nodejsUnder normal circumstances, Node 8.x has been installed successfully.    $ node -v    v8.1.05.7 Light LEDPi provides a set of external IO interfaces, called GPIO (general-purpose input/output).Figure 15. GPIO PinsThe definition of its 40 pins is shown in the figure below.Figure 16. Raspberry Pi 40 PinsNote that the first pin (3.3V) in the upper left corner is a square, and the other pins are round. Turn the Raspberry Pi over, and you can see that one corner of the GPIO is square. In this way, you can confirm which pin eye is 3.3V.Through GPIO, the Pi can be connected with other electronic components. Next, according to Jonathan Perkin's article, connect LED diodes.Figure 17. Raspberry Pi BackA breadboard is needed here. In essence, a breadboard is just a few wires with many holes that can be connected to the wires.Figure 18. Connect with BreadboardThe + pole and the-pole are two vertical wires, the row marked with the numbers 1, 5, and 10 is a horizontal wire. The wires are not connected to each other, and the left and right halves of the breadboard are also not connected to each other.Then, connect the Raspberry Pi, breadboard, LED lights, and resistors according to the diagram below.Figure 19. Parts ConnectionIn the above figure, the red wire represents the positive electrode of the current, which is connected from the first pin (3.3V) of the GPIO to the breadboard. The black wire represents the negative electrode of the current, which is connected from the 6th pin (ground) of the third row of the breadboard. It does not matter which hole they connect to the breadboard, but it must be ensured that a complete circuit can be formed (the direction of the arrow in the figure above). Note that LED diodes also have positive and negative poles, with the long pin indicating the positive pole and the short pin indicating the negative pole. The resistor has no positive and negative poles.After the connection is complete, turn on the power and the LED should light up.5.8 LED Control ScriptNext, we use the Node script to control the LED.First, unplug the positive wire from pin 1 (3.3V) and plug it into pin 11 of row 6 (GPIO 17 in the figure above). The current of this pin can be controlled by the script.Then, create a new experiment directory on the Pi, and install the Node module rpio that controls GPIO.    $ mkdir led-demo && cd led-demo    $ npm init -y    $ npm install -S rpioNext, create a new script led-on.js.    // led-on.jsvar rpio = require('rpio');    // Turn on pin 11 (GPIO17) as output    rpio.open(11, rpio.OUTPUT);    // Specify the output current of pin 11 (HIGH)    rpio.write(11, rpio.HIGH);Run this script and you can see the LED bulbs light up.    $ node led-on.jsCreate a new led-off.js script, just change one line (see here for the complete code).    // led-off.js    //...    // Designate Pin 11 to stop output current (LOW)    rpio.write(11, rpio.LOW);Run this script and the LED bulb should be off.    $ node led-off.jsWith these two scripts, it is easy to make the LED blink. Create a new led-blink.js script.    // led-blink.js    var rpio = require('rpio');    rpio.open(11, rpio.OUTPUT);    function blink() {      rpio.write(11, rpio.HIGH);      setTimeout(function ledoff() {        rpio.write(11, rpio.LOW);      }, 50);    }    setInterval(blink, 100);The above script makes the LED blink 10 times per second.    $ node led-blink.js5.9 HTTP ServerMany things can be done by controlling the LED, such as setting up an HTTP server. Whenever someone visits, the LED will blink.First, install a server module in the directory just now.    $ npm install -S serverThen, create a new script server.js.    // server.js    var server = require('server');    var { get } = server.router;    // ...    server({ port: 8080 }, [      get('/' ,  ctx => {        console.log('a request is coming...');        blink();      }),    ]);    console.log('server starts on 8080 port');Run this script.    $ node server.jsThen, open a command line terminal, access port 8080, and the LED will flash.    $ curl http://localhost:8080After reading the tutorial, you can try it yourself. For example, if you write a test case script, the LED will stay light as long as the test fails, or you can assemble an 8-bit adder. Ⅵ FAQ1. What is Raspberry Pi and how does it work?The Raspberry Pi is a tiny computer about the size of a deck of cards. It uses what's called a system on a chip, which integrates the CPU and GPU in a single integrated circuit, with the RAM, USB ports, and other components soldered onto the board for an all-in-one package.2. What is the Raspberry Pi used for?The Raspberry Pi is a low cost, credit-card sized computer that plugs into a computer monitor or TV, and uses a standard keyboard and mouse. It is a capable little device that enables people of all ages to explore computing, and to learn how to program in languages like Scratch and Python.3. Can Raspberry Pi replace PC?Of course, the Raspberry Pi can't replace most professional desktops, but in general, it can run almost all programming languages and frameworks, from Python to Fortran.4. What do I need to use a Raspberry Pi?What you will need:A Raspberry Pi computer with an SD card or micro SD card.A monitor with a cable (and, if needed, an HDMI adaptor)A USB keyboard and mouse.A power supply.Headphones or speakers (optional)An ethernet cable (optional)5. Which Raspberry Pi is best for beginners?Best Raspberry Pi Starter KitsCanaKit Raspberry Pi 3 B+ Starter Kit 32GB EVO+ Edition Premium Black Case.Vilros Raspberry Pi 3 B+ Complete Starter Kit with Clear Case and 16GB SD Card.Smraza Raspberry Pi 3 B+ Starter Kit, Compatible Pi 3 Model B Case, 16GB SD Card, 2.5 A Power Supply.6. What projects can you do with Raspberry Pi?Best Raspberry Pi Projects for 2021Google Enabled Magic Mirror.Solar-Powered Pi.Game Console.Remote-Controlled 3D Printer.Language Translator.Satellite Tracking Globe.PC Hardware Stats Monitor.Security Camera.7. Which is cheaper Arduino or Raspberry Pi?The two most popular among them are: Arduino and Raspberry Pi. Arduino is based on the ATmega family and has a relatively simple design and software structure. Raspberry Pi, basically is a single-board computer.8. Which programming language is used for Raspberry Pi?Python. One of the most widely used programming languages on the Raspberry Pi is none other than Python. Python has an easy, beginner-friendly syntax (arrangement of words, phrases, in sentences) and a wide adoption rate among the community, giving access to libraries, frameworks, and tools to help users get started.9. Can a Raspberry Pi run Windows?The Raspberry Pi 4 can handle Microsoft Edge, the calculator app, and more, all via the power of Windows 11. It can even run Minecraft, albeit in an undesirable state.10. Can you watch Netflix on Raspberry Pi?Although there are some Android images for the Raspberry Pi, Linux distributions (distros) for the Pi are more stable. And with newfound Widevine DRM support, the Raspberry Pi can comfortably stream Netflix, Hulu, Disney+, HBO Max, and Spotify.11. Can you hack with Raspberry Pi?The Raspberry Pi also runs Raspbian, the official OS of the Raspberry Pi. This Debian-based OS can also be used to learn basic Linux and hacking tools, although it requires much more customization before it's suitable for this.12. Which is better for beginners Arduino or Raspberry Pi?The Arduino board is much simpler to use in comparison to Raspberry Pi. The Arduino board can easily be interfaced with analog sensors and other electronic components using only a few lines of code. ... The coding in Arduino is also easier than Raspberry Pi, the latter requiring knowledge of Linux and its commands.13. How do I put codes into my Raspberry Pi?Open IDLE by selecting the Raspberry Pi logo in the top-left, and click Programming > Python 3 (IDLE). You should be presented with the Python interactive interpreter. To write a program, go to File > New File. Enter in your code.14. Can I run Android on Raspberry Pi?First Look: You Can Now Run Android 12 on Your Raspberry Pi 4 Computer. Even if your smartphone doesn't run Android 12 yet, you can now use Google's latest mobile operating system on a Raspberry Pi 4, 400 or CM4 computer.15. What is the advantage of Raspberry Pi over Arduino?Raspberry Pi is 40 times faster than Arduino, with PI, you can send mails, listen music, play videos, run internet etc. Also as we have stated earlier that it has memory, processor, USB ports, Ethernet port etc. and it doesn't require external hardwares for most of the functions.16. How do I use Raspberry Pi with IOT?Connecting the Raspberry Pi to the Outside World - GPIO PinsTo connect the GPIO to external sensors, you can: Connect the sensors directly to the GPIO pins using jumper wires. Connect the GPIO pins to a ribbon cable, which in turn connects it to a breadboard.17. Which is more powerful Raspberry Pi or Arduino?Given those differences you might think a Raspberry Pi is so much more powerful and capable than Arduino, so you should use that. ... Raspberry Pi has 8. Individual I/O pins in Arduino can drive 40mA while Raspberry Pi GPIO pins can each drive a maximum of 16mA18. How many devices can connect to Raspberry Pi?There is a limit of 30 simultaneously connected devices on Pi 4 - the hardware supports 32 device address slots but one address is kept free for unconfigured devices and one address is reserved by the internal USB2. 0 hub for the USB2. 0 ports.19. How many pins are there on Raspberry Pi board?40 pinsOf the 40 pins, 26 are GPIO pins and the others are power or ground pins (plus two ID EEPROM pins, which you should not play with unless you know your stuff!).20. How much RAM does the Raspberry Pi has?The Raspberry Pi 2 has 1 GB of RAM. The Raspberry Pi 3 has 1 GB of RAM in the B and B+ models, and 512 MB of RAM in the A+ model. The Raspberry Pi Zero and Zero W have 512 MB of RAM. The Raspberry Pi 4 is available with 2, 4 or 8 GB of RAM.21. Why is Raspberry Pi 4 so expensive?Due to supply shortages, the Raspberry Pi Foundation can no longer afford to produce them at that price, and so have had to increase the price to $45. ... To help mitigate this price increase, the company is reintroducing the 1GB version of the RPi 4, which was retired in February 2020.22. How do you do Pi in Google Sheets?Creating the PI Symbol with the CHAR FunctionThe amazing CHAR function, which converts numbers into characters per the Unicode table, can output the symbol for pi in your Google Sheet.

Are you struggling to choose the right hardware for your next high-performance computing project? With the rapid advancements in technology, the lines between FPGAs, ASICs, and GPUs are becoming increasingly blurred, making the decision more complex than ever. Whether you're developing a cutting-edge AI application, a high-frequency trading system, or a power-efficient IoT device, selecting the optimal processing unit is crucial for success. In fact, a recent study shows that hardware selection can impact project performance by over 60% and development costs by up to 200%. This comprehensive guide will demystify the world of FPGAs, ASICs, and GPUs, providing a detailed comparison of their performance, cost, power consumption, and flexibility. We'll explore their unique strengths and weaknesses, delve into real-world applications, and provide a clear roadmap to help you make an informed decision. By the end of this article, you'll have the knowledge and confidence to choose the perfect hardware for your specific needs.Understanding the Basics: FPGA, ASIC, and GPU ExplainedBefore we dive into a head-to-head comparison, let's establish a foundational understanding of each technology. Think of them as different types of tools in a workshop, each designed for specific tasks.What is a GPU (Graphics Processing Unit)?Originally designed to accelerate the rendering of graphics for video games and professional visualization, Graphics Processing Units (GPUs) have evolved into powerful parallel processing engines. Their architecture, consisting of thousands of smaller cores, makes them exceptionally good at handling massive amounts of data and performing the same operation repeatedly. This makes them ideal for tasks that can be broken down into smaller, independent calculations.A modern Graphics Processing Unit (GPU)Key Characteristics:High Throughput: GPUs can execute thousands of concurrent threads, making them perfect for data-intensive tasks.Parallel Processing Power: They excel at handling complex mathematical calculations simultaneously, which is why they are the workhorses of deep learning and scientific simulations.Vibrant Ecosystem: Supported by major players like NVIDIA and AMD, GPUs benefit from mature software libraries and development tools like CUDA and OpenCL, making them relatively easy to program for a wide range of applications.Pro Tip: While powerful, GPUs are notoriously power-hungry. For large-scale deployments, the operational cost of power and cooling can be a significant factor.What is an FPGA (Field-Programmable Gate Array)?Imagine a chip that you can rewire and reconfigure after it has been manufactured. That's the magic of a Field-Programmable Gate Array (FPGA). FPGAs are made up of a vast array of programmable logic blocks and a hierarchy of reconfigurable interconnects. This allows designers to create custom digital circuits tailored to their specific needs, offering a unique blend of hardware-level performance and software-like flexibility.A Field-Programmable Gate Array (FPGA) development boardKey Characteristics:Flexibility and Reconfigurability: FPGAs can be reprogrammed in the field to adapt to new standards, fix bugs, or add new features, providing a significant advantage in rapidly evolving applications.Low Latency: By creating a custom data path, FPGAs can achieve extremely low latency, making them ideal for real-time applications like high-frequency trading and industrial automation.Power Efficiency: For certain workloads, FPGAs can be more power-efficient than GPUs because the hardware is tailored to the specific application, eliminating unnecessary overhead.What is an ASIC (Application-Specific Integrated Circuit)?An Application-Specific Integrated Circuit (ASIC) is the epitome of specialization. As the name suggests, an ASIC is a chip designed for a single, specific purpose. Unlike FPGAs, once an ASIC is manufactured, its function is set in stone. This lack of flexibility is compensated by unparalleled performance, power efficiency, and cost-effectiveness at scale.An Application-Specific Integrated Circuit (ASIC)Key Characteristics:Peak Performance and Efficiency: Because ASICs are custom-designed for a specific task, they offer the highest possible performance and the lowest power consumption.Cost-Effective at Scale: While the initial design and manufacturing costs (Non-Recurring Engineering or NRE) are extremely high, the per-unit cost of ASICs is very low in high-volume production.Compact Form Factor: ASICs can integrate a lot of functionality into a small chip, making them ideal for consumer electronics like smartphones and other mobile devices.Important Note: The high NRE costs of ASICs, which can run into millions of dollars, make them a risky proposition. A single bug in the design can render the entire batch of chips useless, requiring a costly and time-consuming redesign.In-Depth Comparison: FPGA vs. ASIC vs. GPUNow that we have a basic understanding of each technology, let's put them head-to-head in a detailed comparison across the most critical metrics for any project: performance, power consumption, flexibility, cost, and development time.A high-level comparison of FPGA, ASIC, and GPU characteristics.Performance and EfficiencyWhen it comes to raw performance, the answer isn't always straightforward and often depends on the specific workload.ASICs are the undisputed kings of performance for their designated task. Because they are custom-built, every part of the chip is optimized for a single function, leading to the highest possible throughput and the lowest latency. For example, in Bitcoin mining, ASICs significantly outperform both GPUs and FPGAs.GPUs excel at parallel processing tasks. Their architecture, with thousands of cores, is perfect for applications that can be broken down into many small, identical operations, such as training deep learning models or rendering complex graphics. However, their performance can suffer in tasks that require more complex, sequential logic.FPGAs offer a unique balance of performance and efficiency. By allowing for the creation of custom hardware data paths, they can achieve higher performance and lower latency than GPUs for certain applications, especially those that are not easily parallelized. While they can't match the raw performance of an ASIC for a specific task, their flexibility allows them to be optimized for a wider range of applications.Performance comparison of different hardware for AI inference tasks.Power ConsumptionIn today's energy-conscious world, power consumption is a critical factor, especially in large-scale data centers and battery-powered devices.ASICs are the most power-efficient of the three. Their custom design eliminates any unnecessary logic, resulting in the lowest possible power consumption for a given task. This is why they are the preferred choice for mobile devices and other power-sensitive applications.FPGAs are generally more power-efficient than GPUs. By tailoring the hardware to the specific application, they can avoid the power overhead of the general-purpose architecture of a GPU. This makes them a great choice for edge computing and other applications where power is a concern.GPUs are the most power-hungry of the three. Their high-performance capabilities come at the cost of significant power consumption, which can be a major operational expense in large-scale deployments.Flexibility and CustomizationFlexibility is a key consideration, especially in rapidly evolving fields where algorithms and standards are constantly changing.FPGAs are the clear winners in terms of flexibility. Their ability to be reprogrammed in the field allows for easy updates, bug fixes, and adaptation to new requirements. This makes them ideal for applications where the final specifications are not yet set in stone or where the ability to adapt to future changes is important.GPUs offer a good degree of flexibility through software programming. Their mature ecosystem of development tools and libraries makes it relatively easy to develop and deploy a wide range of applications. However, their hardware architecture is fixed, which limits their ability to be optimized for specific tasks.ASICs are the least flexible of the three. Once an ASIC is manufactured, its function is permanent. Any changes or updates require a complete redesign and a new manufacturing run, which is both time-consuming and expensive.CostThe cost of each technology varies significantly, and the best choice often depends on the production volume and the project budget.ASICs have a very high upfront cost, primarily due to the Non-Recurring Engineering (NRE) costs, which can run into millions of dollars. However, for high-volume production, the per-unit cost is extremely low, making them the most cost-effective solution for mass-market products.FPGAs have a moderate per-unit cost and no NRE costs, making them a good choice for low to medium-volume production. The development tools can be expensive, but they are a one-time purchase.GPUs have a moderate to high per-unit cost, depending on the performance level. They have no NRE costs, and the development tools are generally free. This makes them a good choice for a wide range of applications, from individual developers to large-scale data centers.Development TimeTime-to-market is a critical factor in today's fast-paced world, and the development time for each technology can vary significantly.GPUs have the shortest development time. Their mature software ecosystem and high-level programming languages make it relatively easy to get started and develop applications quickly.FPGAs have a longer development time than GPUs. They require specialized hardware description languages (HDLs) like Verilog or VHDL, which have a steeper learning curve. However, the development time is still significantly shorter than for ASICs.ASICs have the longest development time, often taking a year or more. The design process is complex and requires a team of specialized engineers. Any mistakes in the design can lead to costly and time-consuming respins.Comparison TableFeatureGPU (Graphics Processing Unit)FPGA (Field-Programmable Gate Array)ASIC (Application-Specific Integrated Circuit)PerformanceHigh (for parallel tasks)High (customizable)Very High (for specific task)Power EfficiencyLowMediumVery HighFlexibilityMedium (software)Very High (hardware)Low (fixed)Cost (per unit)Medium-HighMediumLow (at high volume)NRE CostNoneNoneVery HighDevelopment TimeShortMediumLongReal-World Applications: Where Do They Shine?Understanding the theoretical differences is one thing, but seeing how these technologies perform in real-world applications is where the rubber meets the road. Let's explore some of the key areas where FPGAs, ASICs, and GPUs are making a significant impact.AI and Machine LearningThe field of Artificial Intelligence is one of the most exciting and rapidly growing areas of technology, and it's a battleground where all three of these technologies are competing for dominance.The diverse hardware landscape of AI and Machine Learning applications.GPUs are the current champions of deep learning training. Their ability to perform massive parallel computations makes them ideal for training the complex neural networks that power today's AI applications. Companies like Google and Facebook rely on massive GPU clusters to train their models.FPGAs are carving out a niche in AI inference at the edge. Their low latency and power efficiency make them perfect for real-time applications like autonomous driving, where quick decisions are critical. Microsoft is using FPGAs in its data centers to accelerate AI inference, and they are also being used in a variety of other edge devices.ASICs are the ultimate solution for high-volume, power-sensitive AI applications. Companies like Google have developed their own custom ASICs, called Tensor Processing Units (TPUs), to accelerate their AI workloads. These custom chips offer the best performance and power efficiency for their specific AI models.Cryptocurrency MiningCryptocurrency mining is another area where the choice of hardware has a dramatic impact on profitability. The goal is to perform as many calculations as possible while consuming the least amount of power.A comparison of different cryptocurrency mining hardware setups.GPUs were the go-to choice for mining in the early days of cryptocurrencies like Bitcoin and Ethereum. Their parallel processing capabilities made them much more efficient than CPUs. While they are still used for mining some altcoins, they have been largely superseded by more specialized hardware for Bitcoin mining.FPGAs offered a significant improvement in performance and power efficiency over GPUs for mining. Their ability to be programmed for specific mining algorithms made them a popular choice for a time. However, their reign was short-lived as ASICs entered the scene.ASICs are now the dominant force in Bitcoin mining. These custom-designed chips are optimized for the SHA-256 algorithm used by Bitcoin, and they offer a level of performance and efficiency that GPUs and FPGAs simply cannot match. The development of mining ASICs has led to an arms race, with companies constantly developing new and more powerful chips.How to Choose the Right Technology for Your ProjectChoosing between an FPGA, ASIC, and GPU can be a daunting task, but by carefully considering your project's specific requirements, you can make an informed decision. Here’s a step-by-step guide to help you navigate the selection process.Project Requirements ChecklistBefore you make a decision, answer the following questions about your project:What is your primary performance metric? Are you optimizing for throughput, latency, or both?What are your power constraints? Is your device battery-powered, or will it be deployed in a data center with ample power?How flexible do you need to be? Are the algorithms and standards for your application still evolving, or are they fixed?What is your budget? Do you have the resources for a high upfront NRE cost, or do you need a solution with a lower initial investment?What is your time-to-market? How quickly do you need to get your product to market?What is your expected production volume? Are you building a handful of prototypes or millions of units?When to Choose a GPUChoose a GPU if:Your application involves a high degree of parallel processing, such as deep learning training or scientific simulations.Time-to-market is a critical factor, and you need to leverage a mature software ecosystem.You are developing a desktop or data center application where power consumption is not the primary concern.You need a flexible solution that can be easily reprogrammed for different tasks.When to Choose an FPGAChoose an FPGA if:Your application requires low latency and real-time processing, such as high-frequency trading or industrial automation.You need a power-efficient solution for an edge computing application.The algorithms or standards for your application are still evolving, and you need the flexibility to update the hardware in the field.You are developing a low to medium-volume product and want to avoid the high NRE costs of an ASIC.When to Choose an ASICChoose an ASIC if:You are developing a high-volume product, and per-unit cost is a critical factor.Your application requires the highest possible performance and the lowest possible power consumption.The function of your device is fixed and is not expected to change over time.You have the time and resources for a long and complex design and verification process.Common Pitfalls to AvoidUnderestimating the NRE costs of ASICs: The upfront costs of designing and manufacturing an ASIC can be staggering. Make sure you have a clear understanding of all the costs involved before you commit to this path.Overlooking the power consumption of GPUs: While GPUs offer impressive performance, their high power consumption can be a major operational expense. Be sure to factor this into your total cost of ownership.Ignoring the learning curve of FPGAs: FPGAs require specialized hardware description languages, which can have a steep learning curve. Make sure you have the right expertise on your team before you choose this option.Frequently Asked Questions (FAQ)Is an FPGA faster than a GPU?It depends on the application. For tasks that can be highly parallelized, a GPU is generally faster. However, for tasks that require low latency and custom data paths, an FPGA can be significantly faster. For example, in high-frequency trading, FPGAs are often preferred for their ability to execute trades in nanoseconds.What is the main advantage of an ASIC?The main advantage of an ASIC is its performance and power efficiency for a specific task. Because it is custom-designed, it can be optimized to a degree that is not possible with general-purpose hardware like GPUs or FPGAs. This makes ASICs the ideal choice for high-volume products where performance and power are critical, such as smartphones.Can I use a GPU for tasks other than graphics?Absolutely! The parallel processing power of GPUs makes them suitable for a wide range of applications beyond graphics, including scientific computing, data analysis, and machine learning. This is often referred to as General-Purpose GPU (GPGPU) computing.Is it difficult to program an FPGA?Programming an FPGA is more complex than programming a GPU or CPU. It requires knowledge of Hardware Description Languages (HDLs) like Verilog or VHDL. However, the development tools have become more user-friendly in recent years, and high-level synthesis (HLS) tools allow developers to use languages like C++ to program FPGAs, which is lowering the barrier to entry.Why are ASICs so expensive to design?The high cost of ASIC design comes from the Non-Recurring Engineering (NRE) costs, which include the cost of designing, verifying, and testing the chip, as well as the cost of creating the photomasks for manufacturing. This process requires a team of highly skilled engineers and can take a year or more to complete. Any error in the design can result in a costly respin of the chip.ConclusionThe debate over FPGA vs. ASIC vs. GPU is not about which technology is definitively “best,” but rather which is the right tool for the job. As we’ve seen, each has its own unique strengths and weaknesses, and the optimal choice depends on the specific requirements of your project. GPUs will likely continue to dominate the world of high-performance parallel computing, especially in deep learning training. ASICs will remain the go-to solution for high-volume, power-sensitive applications where performance is paramount. And FPGAs will continue to shine in applications that require a combination of low latency, power efficiency, and flexibility.Looking ahead, the future of computing is likely to be heterogeneous, with systems that combine all three technologies to achieve the best of all worlds. We are already seeing this trend in data centers, where FPGAs are being used to accelerate networking and storage, while GPUs are used for AI and machine learning. As technology continues to evolve, we can expect to see even more innovative combinations of these powerful processing units.So, what’s the next step for you? Armed with the knowledge from this guide, you are now ready to take a closer look at your project requirements and make an informed decision. Don’t be afraid to experiment and prototype with different technologies to see which one works best for you. The right choice will not only improve the performance of your application but also save you time and money in the long run.

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.