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Warm hints: The word in this article is about 4000 words and  reading time is about 20 minutes.SummaryThe clock is the most important and special signal in the entire circuit. The movement of most of the devices in the system is performed on the edge of the clock. This requires that the delay of the clock signal is very small, otherwise it may cause an error in the timing logic. Therefore, it is very important for the design of FPGA to determine the factors of system clock and the delay of clock to ensure the stability of design. CoreClock in FPGA designPurposeDetermining the influencing factors of clock to ensure the stability of designEnglish nameField Programmable Gate ArrayCategoryDigital electronic circuitFunctionCreating digital circuitsFeatureTotally up to the designer to create a bit fileCatalogsCatalogsⅠ. What is Setup time and Hold timeⅢ. Analyzing with the help of timing diagram3. The composition of the state machine1. Synchronization between single bits and each pulse transmitted has at least 1 cycle width1. Setup timeⅣ. How to increase the clock working frequencyⅤ. An example showing a good method for state machine design2. The input pulse could be less than a synchronous circuit under a clock cycle width 2. Hold time1. Changing the line type for circuit wiringⅥ. The introduction of state machine Ⅱ. A basic model of synchronous design using a single clock2. Splitting the combinational logicⅦ. What we should pay attention when designing the clock in FPGA  IntroductionⅠ. What is Setup time and Hold timeThe clock is the most important and special signal in the entire circuit. The movement of most of the devices in the system is performed on the edge of the clock. This requires that the delay of the clock signal is very small, otherwise it may cause an error in the timing logic. Therefore, it is very important for the design of FPGA to determine the factors of the system clock and the delay of the clock to ensure the stability of the design.Learn how a clock drives all sequential logic in FPGA, from Flip-Flops to Block RAMs; The clock tells you how fast you can run your FPGA;This video demonstrates how to properly deal with multiple clock domains inside your design.1. Setup timeSetup time(Tsu) is defined as the minimum amount of time before the clock's active edge that the data must be stable for it to be latched correctly. Any violation may cause incorrect data to be captured, which is known as setup violation.2. Hold timeHold time(Thd) is defined as the minimum amount of time after the clock's active edge during which data must be stable. Violation in this case may cause incorrect data to be latched, which is known as a hold violation. Note that setup and hold time is measured with respect to the active clock edge only.Figure 1 Shows setup time and hold timeFigure 2 If data will change in tsu then it will cause setup violation and if data will change in thd then it will cause hold violation  DtailⅡ. A basic model of synchronous design using a single clockIn the same module of FPGA design, it often contains the combinational logic and the sequential logic. In order to guarantee the data in this logic interface can be processed steadily, then figuring out the concept of setup time and hold time is very important. Then we could be able to think about this following question:Figure 3 Shows a basic model of synchronous design using a single clockTco: Delay of the data output of the trigger;Tdelay: Delay of the combinational logic;Tsetup: The trigger's setup time;Tpd: Delay of the clock (negligible).T: clock cycleT3: D2 setup timeT4: D2 hold timeIf the first trigger D1 has a maximum setup time of T1max and a minimum of T1min, the combinational logic has a maximum delay of T2max and a minimum of T2min. The question is what conditions setup time T3 and hold time T4 of the second trigger D2 should be met, or what the maximum clock cycle given T3 and T4. This is the thing must be carefully considered in the process of design, because only by clarifying this issue can we ensure that the delay of the  combinational logic designed meets the requirements.Ⅲ. Analyzing with the help of timing diagramNow let us analyze this question with the help of timing diagram: let the input of the first flip-flop be D1, the output be Q1; the input of the second flip-flop be D2, the output be Q2;Given the clock is uniformly sampled on the rising edge, for ease of analysis we would discuss two cases, the first one: Assume that the delay of the clock Tpd is zero, which in fact, is often met in the FPGA design where the unified system clock it is generally adopted and the clock be input through the global clock pin, therefore the internal clock delay can be completely ignored. In this case, it is not necessary to consider the hold time, because each data maintains one clock tick while there is also delay line, that is, the delay based on CLOCK is much smaller than the delay based on data, so the hold time can meet the requirement. The setup time is what we should care about. If the setup time D2 meets the requirement, the timing diagram should be as shown as Figure 4.Figure 4 Shows the timing chart that meets the requirementsFrom the figure 4 we can see:T-Tco-Tdelay>T3That is Tdelay< T-Tco-T3During the setup time D2, the signal can reach D2 through the combinational logic D1, i.e. the data is already in Tsup before the second CLK arrive.Then it meets the requirement of setup time, where T as the clock period, the second flip-flop can pick up D2 on the rising edge of the second clock in this case. {D1 => setup time => hold time => trigger data output delay => combinational logic delay => D2 => ...}If the delay time of the combinational logic is too largeT-Tco-Tdelay < T3 (Tcox<D2 setup time)Then it will not meet the requirements. The second trigger will pick up an unstable state on the rising edge of the second clock, as shown in Figure 5, then the circuit will not work properly.Figure 5 The delay time of the combinational logic is too large to meet the requirementsSo you can deriveT - the Tco - T2max > = T3This is the setup time for D2.From the timing diagram above, it also can be seen that the setup time and hold time of D2 are not related to the setup and hold time of D1, except the combinational logic in front of D2 and the data transmission delay of D1. This is also a Very important conclusion, which shows that the delay has no additive effect.However, if there is a delay in the clock instead, the hold time must be considered in this case, together with the setup time. Most clocks with large delays are designed using asynchronous clocks, which is difficult to guarantee the data synchronization, so it is rarely used in actual designs. At this point, if the setup time and hold time all meet the requirements, you will see the output timing as shown in Figure 6.Figure 6. Clock has a delay but meets the timingIt can be easily seen from figure 5 that the Tpd is relaxed for the setup time, so the setup time of D2 must meet the requirements:Tpd+T-Tco-T2max>=T3 (T3 is the setup time of D2, T2max is the maximum delay of  combinatorial logic, Tpd is the clock delay)As shown in the FIG. 6, since the sum of setup time and hold time is a stable clock period (T), if the clock has a delay and the data delay is small, then the setup time will increase inevitably,  and the decrease of hold time goes with it. If it is reduced to not meet the requirement of hold time D2 , the correct data cannot be collected.That is T-(Tpd-Tco-T2min)T-(Tpd+T-Tco-T2min)>=T4 i.e. Tco+T2min-Tpd>=T4 (D2 hold time )From the formula above we could also figure out that if Tpd = 0, that is to say the delay of the clock is 0, then the same requirements goes with Tco + T2min> T4, however in practical applications the delay of T2 i.e. the delay of line is much larger than the trigger's hold time T4, it becomes not necessary to take the hold time into consideration.Figure 7 The clock has a delay and the hold time does not meet requirementsIn summary, if you do not consider the delay of the clock, the only thing you need to care about is the setup time, or the hold time instead. Then let us think about in FPGA design, how to increase the working clock in the synchronous system. AnalysisⅣ. How to increase the clock working frequencyFrom the above analysis, we can see that the requirements of setup time T3 for the D2 in the synchronization system is as follows:T-Tco-T2max>=T3So it is easy to derive:T>=T3+Tco+T2maxwhere T3 is the setup time Tset of D2, and T2 is the delay time of the combinational logic. In a design, T3 and Tco are both fixed values determined by the device, the only factor that we could control is the input delay of the combination logic T2. Therefore, by reducing T2 as much as possible, the clock working frequency can be increased. In order to achieve the reduction of T2 in the design, there are different comprehensive methods we can use.1. Changing the line type for circuit wiringAltera devices, for example, there are many bars in the quartus timing closure floorplan, so we can slice and dice them into rows and columns: Each bar represents 1 LAB, each LAB has 8 or 10 LEs in. The relationship of their routing delay is as follows: the same LAB (fastest) < the same row and column < different row and column. We could add appropriate constraints to the synthesizer (this should be given appropriate, generally 5% margin adding, for example, if the circuit works at 100Mhz, then adding constraints to 105Mhz is sufficient, because the excessive constraint could do a bad effect instead, and greatly increases the integration time) to make the relevant logic circuit wiring be placed as close as possible, thereby reducing the routing delay.2. Splitting the combinational logicSince the general synchronous circuits are more than a?single?stage latch (as shown in Figure 9), and to make the circuit stable, the clock period must meet the maximum delay requirement, and the maximum?delay of the longest path can be shortened before the operating frequency of the circuit be increased.As shown in Figure 8, we can decompose the larger combinatorial logic into smaller blocks and insert flip-flops in the middle, which can increase the operating frequency of the circuit. This is also the basic principle of the so-called "pipelining" technology.For the upper part of Figure 9, its clock frequency is subject to the delay of the second larger combinational logic. By appropriately distributing the combinational logic, excessive delay between the two flip-flops can be avoided and speed bottlenecks can be eliminated.Figure 8 Splitting combination logicFigure 9 Transferring Combination LogicHow to split the combinatorial logic in design, the better method should be accumulated in practice, but some good design ideas and methods also need to be mastered. We know that at present most of the FPGAs based on 4-input LUTs, if an output criteria corresponding is more than four inputs, then the multiple LUT cascade will be needed, thus introducing the delay of one-stage combinational logic. That is we want to reduce the number of combinational logic, the logic is nothing more than to make the input conditions as few as possible, so that less multiple LUT cascade need to be use, thereby reducing the time delay caused by combinational logic.The pipelining that we usually hear is a way to increase the operating frequency by splitting a large combinational logic (in the middle of which a singer or multiple stages of D flip-flops are inserted, thereby reducing the number of combinatorial logic between registers) to a smaller one. For example, a 32-bit counter, with a very long carry chain, will inevitably reduce the operating frequency, so we can split it into a 4-bit and a 8-bit one, whenever the 4-bit counter counts to 15 and triggers an 8-bit one, which enable the counter to be split and increases the operating frequency.Just as the same, large counters are generally moved out of the state machine, because if they, with usually more than 4 inputs, are used as state transition criteria with other conditions, they will increase the multiple LUT cascade, and then increasing the combination logic.Taking a 6-input counter as an example, we wanted to make a state transition after the counter counted to 111100, now because we put the counter out of the state machine, when it counts to 111011, a signal of "enable" is generated and then trigger the state transition, which obviously reduces the combinatorial logic.3. The composition of the state machineThe state machine generally contains three modules:An output moduleA module that determines what the next state isA module that saves the current stateThe logic used to form these three modules is also different. The output module usually contains both combinatorial logic and sequential logic; the module that determines the next state is usually composed of combinatorial logic; and the module that saves the current state is usually composed of sequential logic. The relationship between these three modules is shown in Figure 10.Figure 10 The composition of the state machineⅤ. An example showing a good method for state machine designThat is why when writing the state machine, the state machine is always divided into three parts according to these three modules. The following example shows a good method of state machine design: -----------------------------------------------------*/module arbiter2 (                    clock , // clock                    reset , // Active high, syn reset                    req_0 , // Request 0                    req_1 , // Request 1                    gnt_0 ,                    gnt_1                );//-------------Input Ports-----------------------------input    clock ;input    reset ;input    req_0 ;input    req_1 ;//-------------Output Ports----------------------------output    gnt_0 ;output    gnt_1 ;//-------------Input ports Data Type-------------------wire    clock ;wire    reset ;wire    req_0 ;wire    req_1 ;//-------------Output Ports Data Type------------------reg        gnt_0 ;reg        gnt_1 ;//-------------Internal Constants--------------------------parameter     SIZE = 3 ;parameter     IDLE = 3'b001 ,            GNT0 = 3'b010 ,            GNT1 = 3'b100 ;//-------------Internal Variables---------------------------reg        [SIZE-1:0] state ;        // Seq part of the FSMwire    [SIZE-1:0] next_state ;    // combo part of FSM //----------Code startes Here------------------------assign    next_state = fsm_function(req_0, req_1);//------------fsm_function--------------//function [SIZE-1:0] fsm_function;input     req_0;    //parameterinput     req_1;    //parameterbegin    case(state)        IDLE :                if (req_0 == 1'b1)                    fsm_function = GNT0;            else if (req_1 == 1'b1)                fsm_function = GNT1;            else                fsm_function = IDLE;        GNT0 :             if (req_0 == 1'b1)                fsm_function = GNT0;            else                fsm_function = IDLE;        GNT1 :            if (req_1 == 1'b1)                fsm_function = GNT1;            else                fsm_function =IDLE;        default : fsm_function = IDLE;        endcaseendendfunction always@(posedge clock)begin    if (reset == 1'b1)        state <= IDLE;    else        state <= next_state;end//----------Output Logic-----------------------------always @ (posedge clock)begin    if (reset == 1'b1)         begin        gnt_0 <= #1 1'b0;        gnt_1 <= #1 1'b0;        end    else         begin        case(state)            IDLE :                 begin                gnt_0 <= #1 1'b0;                gnt_1 <= #1 1'b0;                end            GNT0 :                 begin                gnt_0 <= #1 1'b1;                gnt_1 <= #1 1'b0;                end            GNT1 :                 begin                gnt_0 <= #1 1'b0;                gnt_1 <= #1 1'b1;                end            default :                 begin                gnt_0 <= #1 1'b0;                gnt_1 <= #1 1'b0;                end        endcase        endend // End Of Block OUTPUT_Endmodule Ⅵ. The introduction of state machineState machines are usually written in three segments to avoid excessive combinational logic.All we mentioned above shows how we could use the way of pipelining to split the combinational logic, but in some cases it is difficult for us to do that, and then what should we do?The state machine is such an example that we cannot add assembly line in the state decoding combinational logic. If there is a design of state machine with dozens of states, there is no doubt that its state decoding logic will be very large and this will be the critical path in the design. So what should we do?Just the same way, reducing the combinatorial logic. We can analyze the output of the state, reclassify and redefine them into a group of small state machines. By selecting the input (case statement) and triggering the corresponding small state machine, we can achieve a large state machine splitting into several small state machines. In the ATA6 specification (hard disk standard), there are about 20 kinds of input commands, and each piece of command corresponds to a variety of states. It is unthinkable to do it with a large state machine (nesting), however in the contrary, if you use the case statement to decode the command and trigger the corresponding state machine, in this way the module can run very fast.The key to increasing the operating frequency is to reduce the time delay from register to register, and the most effective method for reduction is to avoid large combinational logic, that is, to try to meet the four-input condition, reducing the number of LUT cascades, that’s mean that we could increase the working frequency by adding constraints, using a way of pipelining and splitting states.Ⅶ. What we should pay attention when designing the clock in FPGA1.Try to use only one clock in a module, and a module here means a module or an entity. In the design of multi-clock domain, it is better to have an extra special module for the isolation of clock domain. This allows the synthesizer to get a better results.2. Unless it is a low-power design, otherwise do not use the gated clock (gllobal Clock buffer such as IBUFG within FPGA) to control the input of clock edge of flip-flop, but use combinational logic and other timing logic (such as frequency divider) to generate signals used as the input of clock edge of flip-flop---all this is to reduce the instability of the design.3. Do not use the signals divided by counter as the clock of other modules, but  with the help of clock enable(CE). Otherwise, this clock-like manner is extremely unfavorable to the reliability of the design, and greatly increases the complexity of the static timing analysis .Ⅷ. Synchronization Between Different Clock DomainsIf two modules in a design using two respective operating clock, then at their interfaces there would emerge a phenomenon which called as Asynchronous Patterns. In order to ensure data correct processed, the two modules must be synchronized.There are usually two cases of different clock domains here (discrete clock source):1. the frequency of two clocks is different;2. the two clocks share a same frequency, but they are actually two separate clocks with no relation to the phase.Just as shown in the following two figures:Figure 11 The frequencies of two clocks are completely differentFigure 12 The frequencies of the two clocks are the same, but the phases are irrelevantThe data transmission between two clock domains usually adopts different synchronization methods according to different bit widths.1. Synchronization between single bits and each pulse transmitted has at least 1 cycle widthThis kind of synchronization is mainly used for the synchronization of some control signals. As shown in Figure 13 below:Figure 13 One bit synchronizer designThe following points are required to be explained for this synchronization:(1) synchronous circuit of figure 12 is actually called "one bit synchronizer", it can only be used for one bit asynchronous signal which must be wider than that of the Current stage’s clock, otherwise it may be unable to adopt this asynchronous signal.(2) why is the circuit in figure 13 can only be used in one bit asynchronous signals?When two or more asynchronous signals (control or address) simultaneously get into the current time domain and take control the circuit of current time domain, problems arise if these signals are all synchronized using the same circuit in FIG. 13. Skews has arisen between two or more asynchronous signals (control or address) due to connection delays or other delays, and then the skew is greatly enlarged via the synchronizer in Figure 13 when getting into the current time domain, or competition may caused and finally leading to an error in the time domain circuit.Figure 14 Problem-passing multiple control signals between clock domainsIf the asynchronous data bus is to enter the current time domain, the circuit in Figure 13 cannot be used either, because data change very randomly and the width of 0 or 1 has nothing to do with the clock pulse of the current time domain, so the circuit in Figure 13 may be unable to adopt the correct data.(3) Please note that the second trigger is not used for avoiding the occurrence of "metastable state", on the contrary, it can prevent the transmission of metastable state. In other words, once the first flip-flop becomes metastable (possibly), due to the second flip-flop, the metastability will not be transmitted to the circuit following.(4) The first-stage trigger has a metastable state, which means it will require a recovery time to stabilize again, or it is also called Withdrawal from metastable state. The recovery time plus the establishment time of the second-stage flip-flop (say more precisely, maybe also minus the clock skew) is less than or equal to the clock period, which can be easily satisfied. This is means thees two stages of flip-flop should be put together as close as possible, without any combinatorial logic between them or excessive skews to the clock, and then the second-stage flip-flop can adopt data stably and preventing the transmission of metastable state.(5) FF1 is the sampling output of FF2, so of course, what is output by FF1 is  what output by FF2, everything is the same except one cycle of delay. Note that “meta-stableit” means that once the data of FF1 enters, its electrical level would be indefinite and maybe incorrect. So although this method can prevent transmission of metastable state, it does not guarantee the data after the two-stage flip-flop is correct. Therefore, this kind of circuit always has a certain amount of fault-tolerance. This applies only to a some error-insensitive cases, but for other sensitive circuits, dual-port RAM or FIFO are better choices.2. The input pulse could be less than a synchronous circuit under a clock cycle width How is that possible? Has it not less than the original clock? For this case, the Feedback shown in Figure 15 below may usually be taken into consideration. The analysis of this circuit is as follows: Assume that the input data is high level, because the first flip-flop FF1 is high-level cleared, then all outputs should also be high and correctly adopted. On the other hand, if the input is low-level, data of FF1 would be forced to clear and the output level is zero, which ensures the correctness of the output.Figure 15 Synchronous circuit--input pulse may be less than one clock cycle width  Book SuggestionBuilding Embedded Systems: Programmable Hardware 1st ed. EditionThis is a book for embedded-system engineers and intermediate electronics enthusiasts who are seeking tighter integration between software and hardware. Those who favor the System on a Programmable Chip (SOPC) approach will in particular benefit from this book. Students in both Electrical Engineering and Computer Science can also benefit from this book and the real-life industry practice it provides.--Changyi GuDigital Integrated Circuit Design Using Verilog and Systemverilog 1st Edition, Kindle EditionFor those with a basic understanding of digital design, this book teaches the essential skills to design digital integrated circuits using Verilog and the relevant extensions of SystemVerilog. In addition to covering the syntax of Verilog and SystemVerilog, the author provides an appreciation of design challenges and solutions for producing working circuits. --Ronald W. MehlerPower Converters with Digital Filter Feedback Control 1st Edition, Kindle EditionThis book builds a bridge for moving a power converter with conventional analog feedback to one with modern digital filter control and enlists the state space averaging technique to identify the core control function in analytical, close form in s-domain (Laplace). It is a useful reference for all professionals and electrical engineers engaged in electrical power equipment/systems design, integration, and management.--Keng C. Wu Relevant information "Discussion on the influencing factors of clock in FPGA design"About the article "Discussion on the influencing factors of clock in FPGA design", If you have better ideas, don't hesitate to  write your thoughts in the following comment area. You also can find more articles about electronic semiconductor through Google search engine, or refer to the following related articles.To Solve the Problems of Cloud Skyrocket--Edge ProcessingFPGAs Power Facial Recognition Technology Was Issued by NECNew Software for C2000 MCUs Eliminates the FPGA in industrial designsCustomisable Ethernet switch designed for embedded applicationsMouser signs Intel FPGA board firm ReFLEX CES

Radio Frequency Identification (RFID) technology has been developed rapidly in recent years. The key is an automatic identification technology which uses radio waves to communicate. Compared with the traditional recognition technology, it has the advantages of fast recognition, large data storage and data updatable.  This is a video about brief introduction to RFIDThe basic principle of the data communication is the electromagnetic coupling between the reader and the electronic tag affixed to the object. This article will take the RFID technology as the research object, analyzing the basic definition of RFID, the components of the system, the working principle, operating frequency, the main application examples and development trend of RFID technology. In this article, we will make some intorduction to RFID and analyze how it will develop in the future.  CatalogI What is RFID?II Structure of RFID system2.1 Basic components of RFID2.2 RFID middlewareIII Basic working principle of RFID   technologyIV RFID operating frequency4.1 Low frequency 4.2 High Frequency4.3 Ultra-high frequency4.4 Active RFID technologyV RFID practical application examples5.1 Necessity of applying RFID technology   to retail logistics5.2 Why to use RFID technology instead of   existing technology5.3 Application of RFID technology in   retail industryVI Development trend of RFID application   system6.1 More powerful system compatibility6.2 System networking6.3 Greater system data volume6.4 High frequency systemFAQI What is RFID?Radio Frequency Identification (RFID) technology, also known as electronic tag, is a communication technology that uses radio signals to identify specific targets and read and write related data. And there is no need to identify the mechanical or optical contact between the system and the specific target. It can achieve fast reading and writing, non-visual recognition, mobile recognition, multi-target recognition, locating and long-term tracking management. The recognition work is not affected by bad environment, and it can achieve fast reading speed, read information safe and reliable. Therefore, RFID technology has a wide range of application prospects. Radio frequency identification is a non-contact automatic identification technology. It can automatically identify the target object and obtain the relevant data through the radio frequency signal. The identification work can be applied to all kinds of bad environment. RFID is a simple wireless system with only two basic devices. It is used to control, detect and track objects. The system consists of an interrogator and many transponders.Due to the rapid development of RF technology, transponders are also called smart tags or tags. The RFID reader can communicate wirelessly with the electronic tag through the antennas, and can read and write the tag identification code and memory data. A typical reader includes a high-frequency module, a control unit and a reader antenna. II Structure of RFID system2.1 Basic components of RFIDRFID system mainly includes four parts: electronic tag, reader, antenna and application software. The following picture is the block diagram of the system:RFID system structureFrom the above diagram, we can see that there are input and output of data in the module of reader and electronic tag, and the energy and clock are also transmitted in the two modules.2.1.1 ReaderReader is a device for reading (or writing) tag information that can be designed to be hand-held or fixed type. Hand-held is a smaller type used by supermarket cashiers; Fixed is a stationary reader placed by a logistics company at the door when goods are stored in a warehouse. As soon as the object swept by, the scan was completed in an instant.Reader working model2.1.2 AntennaAntenna is used to transmit RF signals between tags and readers.2.1.3 TagsTags are made up of coupling elements and chips. Each tag has a unique electronic code attached to an object to identify the target object. The following picture is the query tag diagram of readers. Reader query tag diagram2.1.4 Application softwareApplication software is a part of RFID system, which is software developed for different needs. It can read, write and control electronic tags through readers, and process and count the collected data. 2.2 RFID middlewareIn the application program, the API can connect to the RFID reader and retrieve the data from the RFID tag through the universal application program interface which can be provided by middleware. RFID middleware acts as a bridge between RFID tags and applications.In this way, even when the FRID reader category or application changes, the application still doesn't need to make any changes. It just need to configure the middleware accordingly. This can reflect the flexibility and importance of middleware.Practical application of RFID middlewareThe benefits that the application of RFID middleware can be brought to an enterprise are as follows:- According to their own business requirements and actual usage, enterprises can import the required data into the application software by self-configuring the RFID middleware parameters, which can fully reflect the flexible characteristics of RFID middleware.- The import of RFID data only needs to change the setting of RFID middleware when some changes occur in enterprise application software.- If you need to increase the number of RFID readers, then enterprises only need to do some related RFID middleware settings. It doesn’t need to change any related procedures, which reduce unnecessary trouble, and save time.- It shortens the implementation cycle of RFID application, and enterprises can directly import the relevant data of RFID.  III Basic working principle of RFID technologyA complete RFID system is composed of three parts: reader, tag with transponder and application software system. Its working principle is: Reader sends out the energy of a radio wave at a specific frequency to drive the transponder, and the circuit will send out the internal data. At this time, the reader will receive the data in order and interpret them, then send it to the application for some corresponding processing.RFID working principleThe information exchange between the reader and the transponder is usually half-duplex communication mode. In this case, the reader can provide the passive transponder with energy, timing and other related contents by coupling. In practical application, the object recognition information can be collected, processed and transmitted remotely through Ethernet and so on. Transponder is the main information carrier of its system. At present, most of the transponders in the market are composed of coupling elements (including coils, microstrip antennas, etc.) and passive application units composed of microchips. The reader can control and process the information center according to the structure and technology of RFID system information. Its reader is usually composed of a transceiver module, a coupling module, an interface unit and a control module. IV RFID operating frequencyAt present, the operating frequencies of RFID products are divided into low frequency, high frequency, ultra high frequency and so on. RFID products with different frequencies will have different characteristics. 4.1 Low frequency (125KHz ~ 135KHz)Related operation at this frequency is mainly done by inductive coupling. There is a transformer coupling between the inductor coil and the reader coil. The voltage which can be induced in the antenna of the inductor can be rectified by the action of the relative alternating field of the reader. Features:- Apart from some related effects of metal materials, the general low-frequency system can penetrate any material, but it will not reduce its maximum possible reading distance.- Readers working at low frequencies have no special licensing restrictions on the entire planet.- Low-frequency products have different packaging forms. The disadvantage of the best package is that it is too expensive, but it has a service life of more than 10 years.- The frequency of the sensor working in low frequency ranges from 120KHz to 134 kHz. The wavelength of this band is about 2500m. 4.2 High frequencySensors at this frequency will no longer need a coil to wrap it up. Antennas can be made by etching or printing. The related operations of sensors are usually done by load modulation. That is, by turning on and off the load resistance on the inductor, the voltage on the reader antenna will be changed, which can realize the amplitude modulation of the antenna voltage with the remote inductor. If people use data to control load voltages on and off, the data can be transmitted quickly from the sensor to the reader.Features: - Apart from metallic materials, the wavelength of this frequency can pass through most materials, but it will reduce the reading distance. Sensors often need a distance away from the metal.- Although the magnetic field region at this frequency decreases rapidly , a relatively uniform read - write region can be produced.- The system has good anti-collision property and can read many electronic tags at the same time.- Sensors usually exist in the form of electronic tags. 4.3 Ultra-high frequencyThe ultra-high frequency system will transmit energy by electric field. The energy of the electric field will not decrease rapidly. The reading distance of UHF is relatively long, and the passive system can reach about 10m. It is mainly realized by capacitive coupling.Features: - This frequency band has a good reading distance, but it is difficult to define the reading region.- It has a particularly high rate of data transmission and can read a large number of related electronic tags in a very short time.- The radio waves in the UHF band cannot pass through many kinds of application materials, especially water, dust and other substances. For high-frequency electronic tags, however, the tags need not be separated from metals.- Tag antennas are usually in two forms: long stripes and tags. The antenna has two different shapes: linear and circular polarization. It is designed to meet the needs of different applications in the market. 4.4 Active RFID technologyActive RFID is characterized by large amount of data transmission, long communication distance, high reliability, low transmitting power and good compatibility. Compared with passive RFID, it has obvious technical advantages.The basic ideas of RFID technology are: By adopting advanced technical means, people can automatically identify and manage all kinds of objects and equipment in different states.As a new kind of automatic identification technology, RFID technology has a great potential space for development in China, and it has been applied and developed in radio technology. V RFID practical application examplesIn this chapter, we will mainly expound the logistics analysis of retail industry based on RFID technology.5.1 Necessity of applying RFID technology to retail logisticsThe benefits of using RFID technology are not limited to the benefits of retail itself. With the use of RFID technology to create a new revenue stream, government institutions can reduce the loss and enhance the safety and security. At the same time, logistics companies, library systems can also reduce inventory costs.The application of RFID technology in retail can obtain the following benefits:   - Increase project securityTag items only allow objects to be tracked in a specified range or device. RFID technology can also improve the efficiency of inventory management. After all, inventory management is often a time-consuming and exhausting business for retailers.  - Serialization DataEach item has its unique identification number, so it is convenient to distinguish it from other items.  - Real time information flowThe changing state of a project can be quickly updated throughout the supply chain.  - Reduced manual participationRFID technology can track objects automatically without manual counting , data acquisition and bar code scanning , which can save labor cost and human error. The RFID technology provides a real-time visualization technology that allows inventory managers to monitor inventory supplies in real time. This reduces inventory costs and keeps inventory at an optimal level, which avoids shortage and other phenomena at the same time. 5.2 Why to use RFID technology instead of existing technologyThe question now is: why did retail change existing technology by adopting RFID? RFID technology is very similar to the existing bar code technology and non-contact memory. The use of new technologies can bring financial benefits (such as saving money) and can solve some practical problems that can not be solved by the existing technology. Compared with other automatic recognition techniques, RFID has significant advantages. 5.3 Application of RFID Technology in Retail industryRFID technology has been used in the retail industry such as smart shelf. The smart shelf is a kind of shelf which can prevent the phenomenon of product shortage. The shelf combines the RFID reader. Each unit shelf has a RFID tag that allows readers to track the inventory of their products. The main purpose of smart shelf is to support the replenishment at any time and to keep the shelves never out of stock, thus it has been widely used in retail industry and libraries. On one hand, it provides customers with information about the products; on the other hand, it provides inventory information for retail owners and can accurately locate the goods. The purpose of these applications is to offer better and more effective service to them. The use of these technologies will not be limited. It can make customers feel more effective and easier to shop.VI Development Trend of RFID Application systemIt can be predicted that future RFID systems will have the following technological trends: 6.1 More Powerful System CompatibilityAt present, because of the disunity of standards, products from many manufacturers are incompatible with each other. Therefore, it is required that the system should have a very strong compatibility, so that it can deal with the products of multiple manufacturers. 6.2 System NetworkingIn many applications, the data collected by different systems need to be processed uniformly, and then provided to users for use, which requires the management of RFID systems on a networked basis. The aim is to realize the remote control management of the system. 6.3 Greater System Data VolumeThe future RFID system will deal with a large amount of data, so it is necessary for the system to have a stronger data storage capacity and data processing capacity. 6.4 High frequency systemThe UHF RFID system has many advantages compared with the low frequency system, such as small size, long recognition distance, repeatable reading and writing, and no forgery. Therefore, with the decrease of manufacturing cost, the application of UHF system will be more extensive.  FAQ 1. What is RFID used for?Radio Frequency Identification (RFID) is the wireless non-contact use of radio frequency waves to transfer data. Tagging items with RFID tags allows users to automatically and uniquely identify and track inventory and assets. 2. What is RFID and how it works?RFID is a method of data collection that involves automatically identifying objects through low-power radio waves. Data is sent and received with a system consisting of RFID tags, an antenna, an RFID reader, and a transceiver. 3. What RFID means?Radio Frequency Identification (RFID) refers to a wireless system comprised of two components: tags and readers. The reader is a device that has one or more antennas that emit radio waves and receive signals back from the RFID tag. 4. Is RFID harmful to human?It is a non-ionizing type of radiation, but some researches show that it could have a negative impact on the human body in a long-term period [11, 12]. So, for the safety reasons, manufacturers of the RFID systems have limited the range of the RFID antennas used in their systems. 5. Is RFID tag and FASTag same?FASTag is a device that employs Radio Frequency Identification (RFID) technology for making toll payments directly while the vehicle is in motion. FASTag (RFID Tag) is affixed on the windscreen of the vehicle and enables a customer to make the toll payments directly from the account which is linked to FASTag. 6.What is RFID and its advantages?RFID technology automates data collection and vastly reduces human effort and error. RFID supports tag reading with no line-of-sight or item-by-item scans required. RFID readers can read multiple RFID tags simultaneously, offering increases in efficiency. 7. Why is RFID bad?Some negative effects are that its deadly, if RFID tags combine with static electricity you can die. Another negative effect is that the government is slowly taking away surviving resources and giving ultimatums, such as if you don't get the RFID tracking chip your public assistance will be terminated. 8.What are the disadvantages of RFID?a. Materials like metal & liquid can impact signal.b. Sometimes not as accurate or reliable as barcode scanners.c. Cost – RFID readers can be 10x more expensive than barcode readers.d. Implementation can be difficult & time consuming. 9.How do I charge my RFID FASTag?In order to recharge your FASTag sticker, just hit the Add Money option in your Paytm app. FASTag will automatically reserve some amount from your wallet, which can be used at toll plazas later. Do note that FASTag can be used only after 20 mins of adding money to the Paytm Wallet. 10. Can I use existing RFID for FASTag?If a vehicle already has an RFID tag, it might already be activated. When you buy the vehicle, RFID tag payment was also done. It might also have a minimum balance of INR 100 or 200 as is required by the bank. You can recharge it with your Customer ID or Wallet ID of FASTag. 11. How does RFID work without power?Passive RFID tags have no power of their own and are powered by the radio frequency energy transmitted from RFID readers/antennas. The signal sent by the reader and antenna is used to power on the tag and reflect the energy back to the reader. 12. What are the types of RFID tags?RFID tags can be grouped into three categories based on the range of frequencies they use to communicate data: low frequency (LF), high frequency (HF) and ultra-high frequency (UHF). Generally speaking, the lower the frequency of the RFID system, the shorter the read range and slower the data read rate. 13.How do I know if I have an RFID chip?The best way to check for an implant would be to have an X-ray performed. RFID transponders have metal antennas that would show up in an X-ray. You could also look for a scar on the skin. Because the needle used to inject the transponder under the skin would be quite large, it would leave a small but noticeable scar. 14. Does RFID require power?Active RFID tags possess their own power source – an internal battery that enables them to have extremely long read ranges as well as large memory banks. Typically, active RFID tags are powered by a battery that will last between 3 - 5 years, but when the battery fails, the active tag will need to be replaced. 15. What is the difference between a QR code and RFID?QR codes must always be “read-only”, whereas RFID tags can be “read-write”, depending on the radio frequency that's being used. ... So, not only are RFID tags futuristic and have more uses than QR tags, they also have many more applications. The read range is far superior for an RFID tag.  

Expo electronica--21st International Exhibition of electronic componentsFrom Apr. 17th to 19th in 2018, the EXPO ELECTRONICA,the 21st International Exhibition of electronic components,modules and systems will be held in CROCUS EXPO,MOSCOW,RUSSIA. As an exhibitor of the exhibiton, Kynix Semiconductor sincerely invites you to visit this exhibition. It is believed that you can have a better understanding of our company and we can form a stabler partnership.Following are some information about the EXPO ELECTRONICA. OverviewAs one of the largest international exhibition of electronic components,modules and systems both in terms of the number and importance of its exhibitors in Russia,ExpoElectronica exhibitions holds the title of the “Best exhibition in Russia” on the subject of electronics and accessories in all categories according to the Russian National Exhibition Rating. ExpoElectronica is an effective business platform to attract new clients and increase sales of electronic components, modules and systems to existing clients in Russia. Over 400 companies from 20 countries will take part in 2018 exhibition. More than 11 000 specialists from different regions of Russia and foreign countries are expected to visit the exhibition. expoelectronica-plan Exhibition profileSemiconductors;PCBs; Sensors and control devices; Micro- and nanosystems; Passive components; Displays; Electromechanics and connector technology; Embedded systems; Power suppliers; Electronics manufacturing services (EMS); Wireless components and modules; Automation systems; Microelectromechanical systems; Testing and measurement; Circuit design services; Software; LED products and components; NEW! Industry 4.0 solutionsAddressMoscow, 65-66km MKAD (International Exhibition Centre "Crocus Expo")ThemeBest exhibition in RussiaVenuepavilion 3, 65-66 km Moscow City Ring (MKAD), Moscow, RussiaScaletotal exhibitions area was 14 661 sq.mVisitorsOver 400 companies from 20 countries and more than 11 000 specialists from different regions of RussiaDateApril 17 (Tue.) - 19 (Thu.), 2018Well-Know ExhibitorsState Corporate ‘Rostechnologii’, Roselectronics , RAO ‘UES of Russia’, RUSNANO, Almaz-Antey, Zelenograd Innovation and Technology Centre (ZITT), Skolkovo Innovation Center and other.Russia represented electornic organisationsAngstrem, Micron, Svetlana, Meteor plant, JSC Moscow Electrolamp Plant, scientific research institute of gas-discharge devices Plasma, NPP Istok, NPP Pulsar and other.Our Booth Number D411 How to get to EXPO ELECTRONICAUrban transport:  Myakinino metro station (Arbatsko-Pokrovskaya line) - exit to Pavilion 3.By car: On the outer side of MKAD (66 km) - exit to the territory of Crocus City after the Volokolamsk highway, the index "Crocus City". On the inner side of the Moscow Ring Road (66 km) - the exit under the bridge in front of the Volokolamsk highway, the "Crocus City" signpost.ExpoElectronica mapAbout kynixKynix Semiconductor has founded over 10 years since 2008. These 10 years have witnessed our company's trials of becoming a better and better distributor and supplier in electronic components industry.In 2009, our company established the International Sales Department and became members of TBF and HKInventory. In 2010, we established cooperative relationships with accredited testing organizations like CECCLab, White Horse Lab, AAA...In 2013, we established a strategic partnership with dozens of well-known electronic components manufacturers including TI.In 2015,we reached an electronic components supply strategic partnership with Foxconn.Also ,our B2B trading platform was launched officially,whose members have exceeded 15,000 in 2017. Our partners in electronics field have increased to 700 up to now.In 2017, We attended Korea Electronic Show(KES), we won a lot of new partners and opened up kynix’s world market. Our advantages1.Strong operation system2. Good warehouse management3. Cooperation with advanced international testing companies4. Cooperation with international high standard logistics companies like UPS, DHL, TNT, FedEx5. Competitive supply from SumSung / Micron / BroadCom / Freescale / Atmel / Cypress and etc... After-sales ServicesGurantee1.Each product from Kynix has been given a  warranty period of 1 YEAR .During this period , we could provide free technical maintenance if there are any problems about our products.2.If you find quality problems about our products after receiving them , you could test them and apply for unconditional refund if it can be proved.But it's just on this premise that the product is not used and the packing is not damaged .Commitment to QualityKynix has always been laying emphasis on the quality of its products and maintaining a sound cooperative relation with electronic components manufacturers since its founding. It has been conducting quality-monitoring system following the rigid rules in terms of the quality of the product, delivery, and it's after-sales service.  It is claimed by Kynix that all products sold are 100% authentic. Each product has been tested carefully before being sent to the customer. It is our aim to be responsible for our customers and make them satisfactory. The 2017 Electronic Shows We have attened:In 2017,we attened the Korean Electronic Show whic held from 17 October to 20th October 2017 at the COEX Korea Exhibition Center in Seoul, Korea. Under the theme--Where the Creative Things are, there are more well-known exhibitors such as UNION SEIMITSU CO., LTD.; SILICONE VALLEY CO., LTD.; SANYO DENKI (THAILAND) CO.,LTD.; MORNSUN took part in KES. 2017 Korea Electronic ShowIt is  kynix’s honor to witness KES’s great success.We gained great benefits from KES.Over 10 thousand visitors from all the world saw kynix’s stand and asked about electronic semiconductors every day between exhibition period. What's more,we made cooperations with over 60 partners in the exhibition including Sumsung and LG. Kynix gained great benefits from KES ContactIf you have any questions, please contact us through our emails! Hope the exhibition finishes perfectly! We will be there and waiting for your coming! Want hintOpening hours of the EXPO ELECTRONICA is :April 17 from 10:00 to 18:00 on April 18 from 10:00 to 18:00 on April 19 from 10:00 to 16:00For a free visit you need to register and  receive an e-ticket at https://www.expoelectronica.ru . Without registration, the entrance fee is  500 rubles. 

Warm hints: The word in this article is about 2600 words and  reading time is about 15 minutes. In this article, we will mainly introduce the classification, performance, and development trends of electrical connectors. Connectors, as key components of current or signal connections, are also an important part of the industrial system. Not only in aircraft, rockets, connectors are also used in microphones and televisions, which all come in various forms. It builds bridges between circuits or other components that act as current or signal connections. Catalogs I. What Is A Connector?II. Classification of Electrical ConnectorIII. Basic Performance of ConnectorsIV. The Basic Structure of ConnectorV. Development trend of Electronic Connector Technology in the FutureFAQ  I. What Is A Connector?  Connectors, an electro-mechanical device, generally refers to electrical connectors. That is, a device connects two active devices and transmits current or signal.(Connector)Connectors are a kind of component that electronic engineers often come into contact with. Its function is very simple: to bridge the communication between the blocked or isolated circuits in the circuit, so that the current can circulate. The connector is an indispensable part of an electronic device. If you look at the path of the current flow, you will always find one or more connectors. The form and structure of connectors vary greatly, which is depending on the object, frequency, power, environment, etc. For example, connectors for on-court lights and hard drives, and connectors for rocket ignition are very different. But no matter what kind of connector is, it should ensure that the current flowing smoothly, continuously, and reliably. In general terms, the connector is not just used to connected current. With the rapid development of optoelectronic technology, the carrier of signal transmission in optical fiber system is light, glass and plastic also replaced the wire in the ordinary circuit. However, connectors are also used in optical signal pathways, which act the same as circuit connectors.   (Connector)The birth of the connector came from the manufacturing technology of fighter planes. Aircraft in battle had to be refueled and repaired on the ground, and the duration of stay on the ground was an important factor in the victory or defeat of a battle. Therefore, in World War II, the US authorities are determined to reduce ground maintenance time and increase the combat time for fighter jets. They first unitized the various control instruments and machine parts, and then connect them with the connectors to form a complete system. During repair, the faulty units are taken apart and the new units are replaced and the plane will soon be able to fly into combat. After the war, AT-T Bell Labs successfully developed the Bell telephone system, followed by the rise of industries such as computers, communications, and so on, which gives more opportunities for the development of connectors derived from stand-alone technology. II. Classification of Electrical Connector Due to the increasing diversity of connectors and the emergence of new structures and applications, it is difficult to classify and name the connectors by using a fixed pattern. Here we will discuss the classification of connectors on different basis.   1. By nature of useExternal connectors (for external housing), internal connectors (for internal housing). 2. By level of connectors> Level 1  DEVICE TO PACKING : Refers to the connection between IC chips and pins(Level 1)> Level 2 COMPONENT LEAD TO CIRCCUITRY: Refers to the connection between components and PC boards(Level 2)> Level 3 BOARD To BOARD: Refers to the interconnection of PC boards(Level 3)> Level 4 SUBASSEMBLY TO SUBASSEMBLY: Refers to the connection of subsystems to subsystems(Level 4)> Level 5 SUBASSEMBLY TO I/O PORT: Refers to the connection between subsystems to I/O port(Level 5)> Level 6 SYSTEM TO SYSTEM: Refers to the connection between system to system(Level 6) 3. By Processing MethodCrimp Type, I.D.C Type, Solder Type, Z.I.F Type 4. By Usage ModeWire to Board connector, Board to Board Connectors, Wire to Wire connector, socket, Input / output connector 5. By FormsPCB board connector, Flat cable connector, Coaxial cable connector, Embedded connector, Axial connector, Circular connector, Angular connector, Connectors for printed wiring boards 6. By StructureGeneral connector, Waterproof connector, Environment-resistant connector, Airtight connector, Refractory connector 7. By Operating FrequencyLow frequency connector, High frequency connector(Bounded at 3MHz) 8. By the Universality and Related Technical StandardsLow frequency circular connector, Rectangular connector, Printed circuit connector, RF connector, Fibre connector  (This video illustrates various types of electrical connectors or "Terminals" how they are used and how to connect them.) III. Basic Performance of Connectors The basic performance of the connector can be divided into three major categories: mechanical performance, electrical performance and environmental performance. 1. Mechanical performanceAs far as the connection function is concerned, the insertion force is an important mechanical performance. Insertion force is divided into insertion force and withdrawal force (withdrawal force is also called separating force), whose requirements are different. The maximum insertion force and the minimum separating force are stipulated in relevant standards, which indicates that the insertion force should be small from the application (thus having the structure of low insertion force LIF and no insertion force ZIF), but if the separating force is too small, the contact reliability will be affected. The insertion force and mechanical life of the connectors are related to the coating quality (sliding friction coefficient) of the contact structure (positive pressure) and the alignment accuracy (alignability). 2. Electrical performanceThe main electrical performance of connectors include contact resistance, insulation resistance and dielectric strength. > Contact resistance: High quality electrical connectors should have low and stable contact resistance. The contact resistance of connectors ranges from a few mOhms to tens of mOhms. > Insulation resistance: Insulation resistance is an index of insulation performance between contacts of electrical connectors and between contacts and shells, and its order of magnitude ranges from hundreds of megohms to thousands of megohms. > Dielectric strength: Also called withstand voltage or dielectric voltage, which refers to the ability to withstand rated test voltage between connector contacts or between contacts and housing. > Other electrical performanceElectromagnetic interference (EMI) leakage attenuation is used to evaluate the shielding effect of electromagnetic interference (EMI) of connectors, which is generally measured in the frequency range of 100MHz~10GHz. For RF coaxial connectors, there are also electrical indexes such as characteristic impedance, insertion loss, reflection coefficient, VSWR, etc. Because of the development of digital technology, in order to connect and transmit high-speed digital pulse signal, a new type of connectors, i.e. high-speed signal connectors, have emerged. Correspondingly, in addition to the characteristic impedance, some new electrical indexes have appeared, such as crosstalk, delay skew and so on. 3. Environmental performanceCommon environmental performance includes temperature resistance, moisture resistance, salt spray resistance, vibration and shock resistance, etc. > Temperature resistanceAt present, the maximum operating temperature of connectors is 200℃ (except for a few special high-temperature connectors), and the lowest temperature is-65 ℃). As the current produces heat at the point of contact, resulting in temperature rise when the connector is working. Therefore, it is generally believed that the working temperature should be equal to the sum of ambient temperature and contact temperature rise. In some specifications, the maximum allowable temperature rise for connectors at rated operating currents is classified. > Moisture resistanceThe invasion of moisture will affect the insulation performance of connectors and corrode the metal parts. The constant hygrothermal test conditions are as follows: relative humidity 90%~95% (according to the product specification, up to 98 ℃), temperature 40 ±20 ℃, the test time is prescribed by the product, minimum 96 hours.  > Salt spray resistanceWhen the connector works in an environment containing moisture and salt, its metal structure and contact surface treatment layer may produce electrochemical corrosion, which will affect the physical and electrical performance of the connector. In order to evaluate the ability of electrical connectors to withstand this environment, a salt spray test was prescribed. The connector is suspended in a temperature-controlled test box and ejected with compressed air with a specified concentration of sodium chloride solution to form a salt fog atmosphere. The exposure time is prescribed by the product specification for at least 48 hours. > Vibration and shock resistance They are the important performance of electrical connectors, especially in special application environments such as aviation and aerospace, rail, and road transport. It is an important index to test the mechanical structure of the electrical connector and the reliability of electrical contact. It is clearly stipulated in the relevant test methods. The peak acceleration, duration, impulse waveform, and the time of electrical continuity interruption should be specified in the impact test. > Other environmental performanceAccording to the operation requirements, the other environmental performance of electrical connectors includes leak proofness(Air leakage, liquid pressure), liquid impregnation(the ability of a specific liquid to resist the evil habit) and low pressure, etc.   IV. The Basic Structure of Connector The basic structure of connector includes: contacts, insulator, housing, accessories. (Basic Structure)1. ContactsContact is the core part of the connector to complete the function of an electrical connection. the contact pair is usually made up of positive contact and negative contact, which is electrically connected through the insertion of negative and positive contacts.Positive contacts are rigid parts with cylindrical shapes (round pins), Square column shape (square pins), or flat shapes (inserts). Positive contacts are generally made of brass and phosphor bronze. 2. InsulatorThe insulator, also known as the base or mounting panel (insert), is used to arrange the contacts according to the required position and spacing, and to ensure the insulation between the contacts or between the contacts and the housing. Good insulation resistance, voltage resistance, and processability are the basic requirements of insulator selection. 3. HousingHousing, also called a shell, is the cover of connectors. It provides mechanical protection for built-in insulating mounting panels and pins, and alignment when plugs and sockets are plugged in, thereby securing connectors to the device. 4. AccessoriesAccessories are divided into structural accessories and mounting accessories. Structural accessories are such as rand, positioning keys, dowel pins, guide pins, connecting rings, cable clamps, sealing rings, gaskets, etc. Mounting accessories are blots, nuts, screws, spring coil, etc. Coils, etc. Most of the accessories have standard parts and general parts.  V. Development Trend of Electronic Connector Technology in the Future Connectors, as a key component of current or signal connections, are also an important part of the industrial system. With the rapid development of personal mobile terminals, home intelligent appliances, information and communication industry, transportation and new energy industry, aerospace technology, artificial intelligence, medical electronic devices, and other fields, there are higher requirements for connectors in function, appearance, performance, and use environment. 1. Development trend of miniaturization and integrationIn order to meet the requirements of portable, digital and multifunctional electronic machines, as well as production and assembly automation, electronic connectors must adjust their product structure. Products are developed to small size, low height, narrow distance, multi-function, long life, surface installation, and other directions. Miniaturization means that the center spacing of electronic connectors is smaller, and the high density is the realization of a large core number. The miniaturization of consumer electronics requires miniaturization of components, thinness, and high performance, which also promotes the development of connector products towards miniaturization and small spacing. The miniaturization of components requires higher technical requirements. This requires a strong industrial mold base to effectively support. 2. Development trend of intellectualizationToday is a world of rapid information, no matter what kind of information or technology, people are demanding more and more. With the rapid development of information and communication data, wireless interconnection has come into our daily life. From the application of smartphones, smart wearable, UAVs, unmanned reality, intelligent robot, and so on, the development of electronic connector with IC chip and control circuit is an inevitable trend. This will enable the electronic connector to master the use of electronic devices more intelligently and improve the performance of the connector itself to achieve intelligent wireless bridging. 3. Development trend of high performanceHigh-speed transmission means that modern computers, information technology, and networking technology require the time scale rate of signal transmission to reach the MHz band and pulse time to sub-millisecond, so a high-speed transmission electronic connector (connector) is required.  In order to adapt to the development of millimeter-wave technology, RF coaxial electronic connector has entered the millimeter-wave working frequency band. High current is also an important development direction of many electronic connectors. In the modern high-tech industry, there are many connectors that are used under extreme environmental conditions.  Under the conditions of ultra-high temperature, low temperature, vibration, dampness, and heat, corrosive environment, electronic connectors can be used effectively and normally. This makes connectors more demanding in the selection of raw materials, structural design, processing techniques, new high-temperature-resistant materials, and the new electroplating coating processes.  FAQ 1. What are the 3 types of connectors?Electrical connectors are classified into three types based on their termination ends: board-to-board connectors, cable/wire-to-cable/wire connectors, and cable/wire-to-board connectors. Six levels of interconnection are normally seen in electrical connectors. 2. What are electrical connectors called?Twist-on connectors are also known as wire nuts, wire connectors, cone connectors, or thimble connectors. 3. What is the use of electrical connector?An electrical connector is an electromechanical device used to join electrical conductors and create an electrical circuit. Most electrical connectors have a gender – i.e. the male component, called a plug, connects to the female component, or socket. 4. Which tool is used to attach connectors to wires?PLIERS. ⟹Pliers are tools for gripping and cutting wires or connectors. 5. How many types of electrical connections are there?There are three categories of electrical connectors: light-duty, medium-duty, and heavy-duty. Each category heading refers to how much voltage the connector can handle. A light-duty electrical power connector can carry up to 250 volts (V) of a low current. 6. What are different types of connectors?Types of Connectors:Box-to-box or input/output.Wire-to-board.Chip-to-package.Package-to-board.PC board-to-board. 7. What is a connector?A connector is essentially the social equivalent of a computer network hub. Connectors usually know people across an array of social, cultural, professional, and economic circles, and make a habit of introducing people who work or live in different circles. 8. Why do we use connectors?Connectors are an important tool for writing proficiently in English. Their purpose is to join information together within a sentence. Using connectors correctly will help ensure the meaning of your sentences are clear for readers to understand. 9. How many types of electrical connections are there? There are three categories of electrical connectors: light-duty, medium-duty, and heavy-duty. Each category heading refers to how much voltage the connector can handle. A light-duty electrical power connector can carry up to 250 volts (V) of a low current. 10.What is the most popular type of connector?In the USA for networking and audio/video, the three most popular styles are LC, SC, and ST. LC and SC tend to be the most commonly used styles. Today, ST connectors are seeing more limited usage. You May Also Like:As the Development of Technology ,Connectors Should be Linghter,Smaller and SmarterHeavy Duty Connectors from TE Connectivity Offer A Range of Connectivity Solutions for InstallationHybrid Connector Combines Floating Contact Alignment with High Speed Transmission

This article is mainly to talk about the latest development of electric vehicle power management technology. Electric vehicle systems consist of electric motors, power converters, and energy storage devices such as lithium-ion batteries. This new architecture system must be optimized to maximize system efficiency, enabling the car to achieve maximum travel distance on a single charge. These developments in electronic technology have created conditions for reducing the emissions from transportation. Save our planet and keep the earth away from pollution! This is a consensus voice among scientists and people of insight around the world to reduce greenhouse gas emissions. Vehicles powered by fossil fuel combustion engines are the culprit. Although there are many alternative technologies to promote car travel, the only feasible solution at present is: electric cars.   Catalog   I Electric vehicles (EV) and hybrid electric vehicle (HEV) II Silicon carbide (SiC) power supply for electric vehicles III GaN power supply for electric vehicles IV Utilizing hybrid vehicle transmission system to reduce greenhouse gas emissions V Automotive inverter VI Dual-voltage battery system VII Delphi integration and wiring VIII Electric wheel drive system IX Conclusion FAQ I Electric vehicles (EV) and hybrid electric vehicle (HEV) An electric vehicle (EV) runs on a battery, as does a hybrid electrical vehicle (HEV), except that it also uses a fossil-fueled internal combustion engine as an aid. The technologies that power these cars need to be successful and have a bright future. Energy efficiency is the key. Therefore, intelligent power management mechanisms are needed to maximize the efficiency of converting battery energy into wheel mechanical driving force, thereby increasing single-charge charging. Travel distance, while not increasing carbon emissions, is ideally a significant reduction in carbon emissions. This video describe the operational characteristics of a hybrid vehicle drive train: Introduction to hybrid-electric vehicle energy monitor   II Silicon carbide (SiC) power supply for electric vehicles The weight, size, and cost of an electric vehicle, and the distance travelled by a single charge, are directly related to the efficiency of the power conversion system. SiC power components are ideal for working in the high temperature environments that are common in automobiles. Let us take a closer look at the role of silicon carbide power components in improving system efficiency. Lighter weight means longer mileage. A typical way to reduce the weight, cost, and size of a power conversion system is to increase the switching frequency of the switching regulator. We know that the size and weight of active components such as inductors, capacitors, and transformers can be reduced when operating at higher frequencies. Embrace the silicon carbide (SiC) solution. Although silicon (Si) power devices can also operate at high frequencies, the advantage of SiC is the ability to handle much higher voltages than Si. SiC is a wide band gap semiconductor device, and a wider band gap means a higher critical electric field (a critical electric field is a blocking voltage in an off state). The high voltage capability of wide bandgap (WBG) SiC devices allows them to have lower on-resistance, resulting in faster switching speeds and unipolar operation. Part of the principle is that their carrier frequencies need to be accelerated to much higher speeds (more High kinetic energy) to overcome wider band gaps. Although gallium arsenide (GaAs) and gallium nitride (GaN) also have high critical electric fields and are also improved devices for high-power solutions, SiC has other advantages, such as higher maximum operating temperatures. High Debye temperature, high thermal conductivity (in polycrystalline SiC), rapid switching and high resistivity saturation with low resistivity in the electric field, facilitated generation of lower silica (SiO2) The production cost, as well as the higher threshold energy brings more robust radiation resistance. SiC devices have many key applications in electric vehicles. The existing electric traction drive can convert 85% of the electrical energy into mechanical energy to drive the wheels. This efficiency is quite high, but SiC can also help improve efficiency. The power converter can benefit from improved efficiency because it transfers battery power to the engine and can be used in the battery charger circuit and any needed auxiliary power (Figure 1). Figure 1. SiC power devices have many uses in electric vehicles The SiC power supply that converts 750V to 27V for low-voltage electric vehicles is a good example of using SiC power devices to improve the efficiency of electric vehicles. This architecture increases efficiency from 88% to a staggering 96%, reduces size and weight by 25%, and does not require fans to cool excess heat compared to Si solutions. Table 1 shows some important applications of SiC power devices for electric vehicles. The reference information mentioned in the table can be found by referring to Reference 1 at the end of this article. Table 1. Some SiC applications in the electric vehicle electronics architecture III GaN power supply for electric vehicles Gallium nitride (GaN) also contributed to the improvement of the power supply of electric vehicles. IGBTs widely used in motor drive and DC/DC control have been silicon-based products. These designs typically have switching times on the order of 10kHz to 100kHz, while GaN devices can switch nanoseconds and can easily operate in a 200°C automotive environment. Like SiC, GaN devices can also reduce the size of inductors, capacitors, and transformers in power supply architectures due to their higher switching speeds. They can also reduce the overall size and weight due to the shrinking size of passive components. We will analyze their efficacy based on the chemical composition of electric vehicle batteries, such as lithium-based chemistry and NiMH with high energy density. As described in the previous SiC device section, the efficiency of the power conversion architecture also needs to be improved in order to enable longer distances for a single charge. The switching speed and minimum on-resistance of silicon devices have reached their maximum limit, and GaN seems to be a viable solution that exceeds these limits. Experiments show that if the switching frequency can be increased by 5 times, the inductor and capacitor can be reduced to one-fifth the size. Today's GaN technology can support very high speeds. GaN power devices perform quite well in four key areas: high temperature operation, higher breakdown voltage, low on-resistance, and nanoscale switching speeds for higher operating frequencies. GaN is similar to SiC in terms of these advantages. There are two differences between them: LEDs and RF transistors always use GaN; many silicon manufacturing processes are compatible with GaN processes, which reduces wafer costs and processes compared to the higher substrate costs of SiC. cost. Since the reliability problem was solved as early as 2003, today's technology has achieved the first batch of GaN high electron mobility transistor (HEMT) devices already in production. These are normal conduction devices, so the gate voltage of 0V will become conductive, and any voltage less than 0V will turn the device off. The SiC substrate was used early. Once the Si substrate is perfectly integrated with GaN, the production cost can be significantly reduced. The new cascaded architecture implemented in 2014 changed the ever-changing devices into normally-off devices. Since then, the drive technology has made great progress, the integration is getting higher and higher, and the power inverter has also made significant progress. GaN devices also perform well in battery chargers for electric vehicles, which consist of AC/DC converters plus DC/DC converters. This combination is a power factor controller (PFC) (Figure 2). Figure 2: A typical electric vehicle power architecture With GaN, coupled with higher switching speed GaN HEMTs, smaller passive devices can be realized. At higher frequency conditions, using a smaller inductor can make the ripple current of the power supply architecture lower, improve the power factor, and get a capacitor with a smaller size and lower cost. Lower ripple currents also have less stress on the capacitors, increasing their reliability and lifetime. Over the past few years, the reliability of GaN has been raised to a very high standard, which is the key to the use of GaN in automobiles. IV Utilizing hybrid vehicle transmission system to reduce greenhouse gas emissions At present about 72% of traffic emissions are generated by cars driving on the road. Improving the design of the hybrid powertrain drive system to increase its efficiency is the primary means of reducing emissions. One approach is to increase the efficiency of the DC-link voltage control architecture, which means that first it is necessary to increase the power converter efficiency of the series hybrid electric vehicle drive system. The DC-link is usually connected to three drive systems: a primary power supply consisting of a three-phase rectifier; a secondary power supply consisting of a dual active bridge (DAB) DC/DC converter; and a propulsion load consisting of a three-phase inverter ( Figure 3). They relate to tandem hybrid cars. Figure 3: Block diagram of the drive train of a hybrid vehicle In a design topology where the DC-link and battery voltages are not equal, an intermediate DC/DC converter solution is required. The paper "Voltage Control Methods for Improving Efficiency of Power Circuits in Series Hybrid Electric Vehicles" (Reference 3) describes many methods for studying different architectures and solutions for various DC-link voltage and DC/DC converter control. . The following will discuss the proportional control law that controls the dynamic DC-link voltage to achieve the phase shift between the waveforms of the gate switching of the DAB DC/DC converter bridge. This converter is located between the DC-link and the battery of a series hybrid vehicle drivetrain, as shown in Figure 4. In this case, the controller lowers the power consumption of the DC/DC converter and the entire drive system. Figure 4: Hybrid driveline interconnection diagram in the control schematic In this model, the diesel engine is the main power source of the hybrid vehicle, and the DC battery is the secondary power source. The supervisory control system (SCS) controls the ratio of power provided by the two power sources based on battery state of charge (SOC) and motor load. In fact, in this series hybrid vehicle, the DC-link voltage imposes restraint conditions on the ideal working area of PMSM and PMSG corresponding to the unit modulation index, so that the system can avoid signal distortion and reduce system efficiency. Overshoot state. Keeping the modulation index close to 1 can increase the total efficiency of the power circuit in the drive system, thereby maximizing the efficiency of the inverter and the rectifier, and the switching process is the main factor of its efficiency loss. Therefore, reducing the switching voltage can improve efficiency. This permanent zero pressure switch (PZVS) mechanism that minimizes power loss is best suited for cars with high mixing factors, especially in urban environments. The mixing factor (HF) is the ratio of the installed power from the power source to the total installed power. This mixing factor affects the fuel consumption in hybrid vehicles. V Automotive inverter The main power inverter controls the electric motor in the electric drive system and is an important component in the hybrid/electric vehicle. Power inverters, like engine management systems (EMS) in internal combustion engine cars, determine driving behavior. This inverter is suitable for any motor, such as synchronous, asynchronous or brushless motor, controlled by an integrated electronic PCB board. This PCB is specifically designed by automotive manufacturers to minimize switching losses and maximize thermal efficiency. The other function of the inverter is to capture the energy released by the regenerative brake and feedback to charge the battery. The distance traveled by hybrid/electric vehicles is directly related to the efficiency of the main inverter (Figure 5). Figure 5: Infineon main inverter block diagram in a hybrid/electric vehicle VI Dual-voltage battery system Managing batteries in hybrid and electric vehicles requires high-voltage technology. Dual-voltage systems incorporating 12V and 48V batteries require bi-directional DC/DC conversion, as shown in Figure 6, with the goal of protecting the circuit and supporting architectural functions. Figure 6: Bidirectional DC/DC converters from 48V to 12V In addition, automotive architecture designs typically have a single-phase 3.5kW or 7kW on-board charger module (OBCM) for charging an electric vehicle or plug-in hybrid electric vehicle (PHEV) from the grid. In contrast, electric vehicles and plug-in hybrid vehicles can be used as energy sources, and can also be used as energy storage devices in smart grids that integrate renewable energy. Smart grid work takes into account the smart charging and discharging of electric vehicles and plug-in hybrid vehicles. This is why OBCM must be a bi-directional DC/DC charger. The best architecture for this design is a boost series of resonant bi-directional topologies, as shown in Figure 7. It operates above the resonant frequency, has a zero-voltage switching function, and has maximum power transfer performance at the minimum switching frequency point. Compared to unidirectional power converters, this technology replaces diode rectifiers with MOSFET rectifiers. This solution also has higher efficiency and wider battery capacity. One of the major drawbacks of this architecture shown in Figure 7 is that the rectifier bridge has large losses when it is turned off. This problem must be addressed in future designs. Figure 7: Designers sometimes use a modulated DAB converter to control simple high-frequency isolation VII Delphi integration and wiring It is amazing that Delphi integrates all of the components discussed in this article and some of the other hybrid electric vehicle power electronics (Figure 8). Figure 8. Delphi achieves high integration in hybrid/electric vehicles It is also important to use suitable internal connectors in hybrid/electric vehicles (Figure 9). Figure 9. The key element of a hybrid/electric car is to minimize the quality     VIII Electric wheel drive system “Design and implementation of electric drive systems for in-vehicle electric vehicle applications” (Reference 8) proposes a hub drive system for hybrid and electric vehicles, and a hub-drive hybrid vehicle that provides computing performance. The SIMULINK model has been successfully developed. Two 14kW DC brushless DC (BLDC) motors are manufactured according to the literature and are installed in the rim of the hybrid vehicle wheels. In addition, two independently driven rear wheels are also mounted on Fiat's Linea. By detecting the angle of the steering wheel, electronic control technology replaces the mechanical differential device. The electric drive control system of the car and the electronic control unit (ECU) communicate via the CAN bus. A successful cascade is achieved between the electrically driven rear wheel and the ICE-driven front axle. Figure 10. A rear-wheel brushless DC motor image This design chose a brushless DC motor with a concentrated coil because it has a very low power-to-weight ratio and high efficiency, and it is easy to control. Figure 11. Exploded view of a direct-drive brushless DC motor in wheel rims and motor-generator units The brushless DC motor power drive consists of an integrated power module (IPM), an 8-bit microcontroller and an electronic control system. Driver software development for IGBT converter control and motor pulse width modulation (PWM) voltage control. The system has optocoupler isolation, current and temperature protection, and the system is also embedded with speed, current and voltage sensors. In summary, this article describes some recent developments in the power management of electric vehicles and hybrid vehicles. In the future, there will certainly be more development results that will be further improved to benefit our planet. IX Conclusion Electric propulsion technology requires the integration of a completely new architecture of the powertrain in the vehicle. This newly added component requires a multidisciplinary and in-depth study of the corresponding system components. Electric vehicle systems consist of electric motors, power converters, and energy storage devices such as lithium-ion batteries. This new architecture system must be optimized to maximize system efficiency, enabling the car to achieve maximum travel distance on a single charge. These developments in electronic technology have created conditions for reducing the emissions from transportation.   FAQ   1. What is energy management system in electric vehicles? Energy management strategies are the algorithms that decide the power split between engine and motor in order to improve the fuel economy and optimize the performance of HEVs. ... A lot of research work has been conducted for energy optimization and the same is extended for Plug-in Hybrid Electric Vehicles (PHEVs).   2. What is EV technology? EVs (also known as plug-in electric vehicles) derive all or part of their power from electricity supplied by the electric grid. They include AEVs and PHEVs. AEVs (all-electric vehicles) are powered by one or more electric motors. They receive electricity by plugging into the grid and store it in batteries.   3. What is the biggest challenge with electric vehicles? The major challenge is costs. Battery technology is expensive, and because batteries in electric cars need to be able to hold massive amounts of charge to make the cars practical for most drivers, they have to be built using expensive materials, most of which are tough to procure.   4. Why electric cars are bad for the environment? Nevertheless, at the end of the manufacturing process, electric cars are the ones generating more carbon emissions, according to the Union of Concerned Scientists. Why is this? Because electric cars store energy in large batteries (the larger they are, the bigger their range is) that have high environmental costs.   5. What are the main problems with electric cars? The biggest problem with EVs is range. While a plug-in hybrid can count on gasoline as a backup, EVs can't. An EV like the Tesla Model S can travel nearly 400 miles on a single charge, but not all EVs can make it quite that far. EVs like the Model S tend to be pretty expensive too.   6. What is meant by electric vehicle? An EV is a shortened acronym for an electric vehicle. EVs are vehicles that are either partially or fully powered on electric power. Electric vehicles have low running costs as they have less moving parts for maintaining and also very environmentally friendly as they use little or no fossil fuels (petrol or diesel).   7. How do electric vehicles work? Electric cars function by plugging into a charge point and taking electricity from the grid. They store the electricity in rechargeable batteries that power an electric motor, which turns the wheels. Electric cars accelerate faster than vehicles with traditional fuel engines – so they feel lighter to drive.   8. What are the types of electric vehicles? There are two basic types of EVs: all-electric vehicles (AEVs) and plug-in hybrid electric vehicles (PHEVs). AEVs include Battery Electric Vehicles (BEVs) and Fuel Cell Electric Vehicles (FCEVs).   9. Do electric cars run on AC or DC? Electric cars can use AC or DC motors: If the motor is a DC motor, then it may run on anything from 96 to 192 volts. Many of the DC motors used in electric cars come from the electric forklift industry.   10. Are there any benefits of owning an electric car? They can reduce emissions and even save you money. Fueling with electricity offers some advantages not available in conventional internal combustion engine vehicles. Because electric motors react quickly, EVs are very responsive and have very good torque.  

Today in this article we will discuss about how PCB is developed and its industrial trend. Printed circuit board, also called PCB, is an important electronic component and the support of electronic components, which also have a circuit in which a metal conductor can be connected to an electronic component. Nowadays electronic equipment requires high performance, high speed and thin miniaturization. As a multidisciplinary industry, PCB is the key technology of high-end electronic equipment. It plays an important role in electronic interconnection technology. Introduction to how PCB worksCatalogI PCB overviewII. Main types of PCB2.1 Single-sided boards2.2 Double-sided boards2.3 Multi-layer boardsIII Industrial chain of PCB3.1 Glass fiber cloth3.2 Copper foil3.3 Copper clad laminateIV Development of PCB industry in ChinaFAQI PCB overviewTraditional circuit boards are referred to as printed circuit boards because the circuit and its surface are created using the printing etching inhibitor method. At the moment, most circuit boards are made by using an etching inhibitor (film pressing or coating), and then etching is used to make the circuit board after exposure and development.Due to the continuous miniaturization and refinement of electronic products, most of the current circuit boards are coated with etching inhibitors (film pressing or coating). After exposure and development, the board will be etched to form the final circuit board. PCBs have progressed from single-sided to double-sided, multilayer, and flexible boards, and this trend is expected to continue. Because of its ongoing advancements in the areas of high precision, high density, and high reliability. PCB maintains a strong vitality in future electronic equipment development projects due to its continuous development of high precision, high density, and high reliability, reducing volume, cost, and improving performance.Printed circuit boardThe discussion of the development trend of the future PCB manufacturing technology at home and abroad is almost consistent, that is, developing toward the direction of high density, high precision, fine aperture, fine wire, fine spacing, high reliability, multilayer, high speed transmission, light weight and thin shape. At the same time, it is aimed to increase productivity, reduce costs, reduce pollution, adapt to multi-species and small run production during manufacturing. The technical development level of printed circuit is represented by the line width, aperture and the ratio of thickness to aperture of printed circuit.The creator of the printed circuit board was an Austrian called Paul Eisler. In 1936, he first used a printed circuit board in a radio. In 1943, Americans mainly applied this technology to military radios. Then in 1948, this invention was officially approved for commercial use in the United States.  Since the middle of 1950s, printed circuit boards have been widely used.Before the emergence of PCB, the interconnection of electronic components was accomplished by direct connection of electrical wires. Nowadays, wires exist only for laboratory applications. Printed circuit boards (PCB) have definitely occupied the position of absolute control in the electronic industry. II Main types of PCBAccording to the number of circuit layers, it can be divided into single-sided board, double-sided and multilayer board. The common multilayer board is usually 4 or 6 layers, and the complex multilayer board can have dozens of layers. Printed circuit boards are mainly divided into three types:2.1 Single-sided boardsOn the most basic PCB, the parts are concentrated on one side and the wire will be on the other (when there is patch element, it is on the same side as the wire, and the plug-in device is on the other side). Because the wire only appears on one side, this type of PCB is called single-sided board. The single-sided board has many strict restrictions on the design circuit (since there is only one side, the wiring cannot intersect and have to go around a separate path), so only the early circuits use this type of board.2.2 Doublesided boardsThere are wiring on both sides of this kind of circuit board.However, to use these two sides of the wire, you must have an appropriate circuit connection between the two sides. The "bridge" between these circuits is called “via”. The via hole is a small hole filled or coated with metal on the PCB, which can be connected to both sides of the wire. It can be connected to two sides of the wire. Because the area of the double-sided board is twice as large as that of the single panel,  it solves the difficulty of wiring interleaving in the single panel (it can get to the other side through the hole), so it is more suitable for the circuit which is more complicated than the single sided.2.3 Multi-layer boardsIn order to increase the area in which wiring can be made, the multilayer board is made up of more single or double-sided wiring boards. A printed circuit board with one side as the inner layer, two single sides as the outer layer or two sides as the inner layer, and two single sides as the outer layer, which is interlinked with conductive patterns according to the design requirements, is composed of four layers and six layers of printed circuit boards, also known as multilayer printed circuit boards (PCB). The number of layers on the board does not mean that there are several independent wiring layers. In special cases, an empty layer is added to control the thickness of the board, and the number of layers is usually even, and contains the outermost two layers. Most motherboards are 4 to 8 layers, but technically we can do nearly 100 layers of PCB. Large scale supercomputers mostly use quite many layers of motherboards. However, because such computers have been replaced by clusters of many common computers, super multilayer boards have been gradually unused. Because the layers in the PCB are tightly combined, it is generally not easy to see the actual number, but if you look closely at the motherboard, you can see it. Also there are two kind of boards called rigid and flexible printed boards. > Rigid and Flexible Printed BoardsDivided into rigid circuit boards, flexible circuit boards and rigid-flexible printed circuit boards. The PCB shown in the first picture below is generally referred to as the rigid PCB, and the yellow connection line in the second picture is called flexible PCB. The intuitive difference between a rigid PCB and a flexible PCB is that the flexible PCB is flexible. The common thickness of rigid PCB is 0.2mm / 0.4mm / 0.6mm / 0.8mm / 1.0mm / 1.2mm / 1.6mm / 2.0mm etc. The common thickness of flexible PCB is 0.2mm. The thickening layer is added to the back where the parts are to be welded , and the thickness of the thickened layer varies from 0.2 mm to 0.4 mm. TThe purpose of understanding these is to provide them with a spatial reference for the design of a structural engineer. The common materials for rigid PCB include: phenolic paper laminates, epoxy paper laminates, Polyester glass felt laminates, epoxy glass cloth laminates; flexible PCB materials include: polyester film, polyimide film, ethylene propylene fluoride film.Rigid boardFlexible board III Industrial chain of PCBAccording to the upstream and downstream classification of the industrial chain, PCB industry can be divided into raw materials - CCL (copper-clad laminate) - PCB (printed circuit board) - electronic product application. The relationship is simply expressed as: 3.1 Glass fiber clothGlass fiber cloth is one of the raw materials of copper clad plate, which is made of glass fiber yarn and account for about 40% of the cost of copper clad laminate (thick plate) and 25% (thin plate). Glass fiber yarn is calcined into liquid state from raw materials such as silica sand in the kiln, then pulled into very fine glass fiber through extremely small alloy nozzles, and then hundreds of glass fibers are twisted into glass fiber yarn. The manufacture of glass fabric is similar to that of weaving enterprises. It can control production capacity and quality by controlling rotation speed, and the specifications are relatively single and stable. Since World War II, there has been almost no significant change in specifications.Unlike CCL, prices of glass fabrics are the most affected by supply and demand, fluctuating between $0.50-1.00 a meter in recent years. Taiwan and mainland China account for about 70% of the world's production capacity.3.2 Copper foilCopper foil is the raw material that accounts for the largest proportion of the cost of copper clad laminate, about 30% of the cost of copper clad plate (thick plate) and 50% (thin plate). Therefore the price increase of copper foil is the main driving force of the price increase of copper clad laminate. The price of copper foil is closely reflected in the change of copper price. However, the bargaining power is relatively weak. With the rising copper prices, copper foil manufacturers are in a difficult situation, and many enterprises have been forced to close down or be annexed. Even if copper clad laminate manufacturers accept copper foil price increases, copper foil manufacturers are still in a general loss. Another wave of price increases is likely to occur in the first quarter of 2006, possibly driving up CCL prices due to the price gap. 3.3 Copper clad laminateCopper clad laminate (CCL) is a direct raw material of PCB, which uses epoxy resin as fusion agent to press glass fiber cloth and copper foil to make printed circuit board (PCB) after etching, electroplating and multilayer laminate pressing. The copper clad laminate industry is not in high demand for capital, about 3 million to 40 million yuan, and can be stopped or converted at any time. In the upstream and downstream industrial chain structure, CCL has the strongest bargaining power. It has a strong voice in the procurement of glass fiber cloth, copper foil and other raw materials , and as long as the demand of downstream is good, the manufacturer of CCL can transfer the pressure of rising costs to the downstream PCB manufacturers. IV Development of PCB industry in ChinaThe development of PCB in China began in 1956. In 1963-1978, it is gradually expanded to be the PCB industry. More than 20 years after the reform and opening up, due to the introduction of foreign advanced technology and equipment, single-sided board, double-sided board and multi-layer board had a rapid development. The domestic PCB industry has gradually developed from small to large scale.Due to the concentration of downstream industries and relatively low labor and land costs, China has become the region with the strongest development momentum. In 2002, China became the third largest output country of PCB. In 2003, the output value and import and export volume of PCB exceeded $6 billion, which overtaking the United States for the first time and becoming the second largest output country in the world. The proportion of output value also increased from 8.54% in 2000 to 15.30%, nearly doubling. In 2006, China has replaced Japan as the world's largest PCB production base and the most active technology development country. China's PCB industry has maintained a high growth rate of about 20%, which is far higher than that of the global PCB industry. In terms of production composition, the main products of China's PCB industry have shifted from single-sided and dual-sided to multilayer, and are being upgraded from 4-6 layers to more than 6-8 layers. With the rapid growth of multilayer printed board, HDI board and flexible boards, China's PCB industrial structure is gradually being optimized and improved. However, although China's PCB industry has made considerable progress, there is still a big gap compared with advanced countries, and there is still much room for improvement in the future. First of all, China's entry into the PCB industry is relatively late and there are no specialized PCB research and development institution. There is a big gap between the research and development capabilities of some new technologies and foreign manufacturers. Secondly, in terms of product structure, the production of medium and low laminates is still dominated. Although FPC and HDI boards are growing rapidly, the proportion is still low because of its small base. Most of our PCB production equipment depends on imports, and some core raw materials can only rely on imports. The industrial chain is incomplete, which also hindered the domestic PCB series enterprise's development step.  FAQ 1. What is PCB?A printed circuit board, or PCB, is used to mechanically support and electrically connect electronic components using conductive pathways, tracks or signal traces etched from copper sheets laminated onto a non-conductive substrate. 2. What is PCB and types of PCB?A printed circuit board (PCB) is a thin board made from fiberglass, composite epoxy, or other laminate materials. PCBs are found in various electrical and electronic components such as beepers, radios, radars, computer systems, etc. Different types of PCBs are used based on the applications. 3. What can a PCB be used for?Printed circuit boards (PCBs) are used to mechanically support and electrically connect electronic components using conductive pathways, tracks or signal traces etched from copper sheets laminated onto a non-conductive substrate, employed in the manufacturing of business machines and computers, as well as communication ... 4. Why are PCB green?It is due to the solder mask, which protects the copper circuits printed on the fibre glass core to prevent short circuits, soldering errors, etc. ... The colour of the solder mask gives the board its appearance. 5. What is PCB and its advantages?Compact Size and Saving of Wire. A characteristic PCB includes a large number of electronic components. On a Printed circuit board, the interconnection between the components is made through copper tracks instead of using a number of current carrying wires. It makes the interconnections less bulky. 6. How long does it take for PCBs to break down?3.5 to 83 days. The time it takes for half of the amount of PCBs (initially) present to be broken down ranges from 3.5 to 83 days for molecules with 1 to 5 chlorine atoms. In water, PCBs are essentially broken down by the effect of sunlight (photolysis). 7. What is the disadvantage of PCB?Disadvantages: Easy to Cause Handling Damage. Process Uses a Carcinogen (Thiourea) Exposed Tin on Final Assembly can Corrode. 8. Which PCB design software is the best for beginners?Top Best PCB Design Software of 2021a. PROTEL (Altium Designer) b.PADS (PowerPCB) c. ORCAD. d. Allegro. e. Eagle（Easily Applicable Graphical Layout Editor）f. Kicad.g. EasyEda.h. Fritzing. 9. What are the advantage of flexible PCB?The flexible circuit board are designed for saving room and improving the flexibility to meet a smaller and higher density mounting design, it also helps to reduce the assembly process and enhance reliability. 10. Why do we use PCB instead of breadboard circuit?The advantages of a printed circuit board: the board is permanent to have an electronic device worked. PCB has a better current carrying capacity comparing to a breadboard, you can make your traces wider to take more current so that work well. ... You can mount heat-sinks to the board so that have them rigid. 11. What PCB means?Printed-Circuit-BoardA printed circuit board, or PC board, or PCB, is a non-conductive material with conductive lines printed or etched. Electronic components are mounted on the board and the traces connect the components together to form a working circuit or assembly. 12. Why are PCBs dangerous for humans?PCBs are a probable human carcinogen.Studies of PCBs in humans have found increased rates of melanomas, liver cancer, gall bladder cancer, biliary tract cancer, gastrointestinal tract cancer, and brain cancer, and may be linked to breast cancer. 13. What are PCBs in electronics?A printed circuit board, or PCB, is used to mechanically support and electrically connect electronic components using conductive pathways, tracks or signal traces etched from copper sheets laminated onto a non-conductive substrate. 14. Why are PCB green?It is due to the solder mask, which protects the copper circuits printed on the fibre glass core to prevent short circuits, soldering errors, etc. ... The colour of the solder mask gives the board its appearance. 15. What is PCB and its role?A process control block (PCB) is a data structure used by computer operating systems to store all the information about a process. It is also known as a process descriptor. When a process is created (initialized or installed), the operating system creates a corresponding process control block. 16. Which software is best for PCB design?- NI Multisim.- KiCad EDA.- Autodesk EAGLE.- DipTrace.- Ultiboard.- CAM350.- ExpressPCB Plus.- SolidWorks PCB.