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OverviewThe panel indicators are among the most essential parts of electronics and industrial automation. They are like eye signals that convey critical information about the condition of the equipment or the process. Panel indicators are essential for engineers, technicians, and hobbyists because they know a lot about designing and maintaining efficient systems.  What are Panel Indicators?Panel indicators or pilot lights are tools that show the condition of the equipment. LED lights, neon lamps, and incandescent bulbs are examples of their uses. The indicators are primarily employed in control panels, machinery, and other industrial equipment to inform power status, faults, or operational readiness. Types of Panel Indicators1. LED IndicatorsMost people's favorite choice is the LED panel indicators, as they are energy-efficient, have a long life span, and are compact. When they are on, these indicators provide the light that tells if a system is working. The LED indicators are color-coded in red, green, yellow, and blue, usually used to indicate a specific condition or status. A likely circumstance is that a green LED indicates a system that is fully working and operational, while a red LED indicates some fault or problem. 2. Incandescent IndicatorsIncandescent indicators, called Filament indicators, work with a small incandescent bulb that produces light. Though not as energy-efficient as LEDs, these indicators have been the trend in different applications because of their simple design and low cost. Incandescent indicators are usually found in various lens colors, such as red, green, and amber, and they symbolize different system states or conditions. 3. Neon IndicatorsNeon indicators or neon lamps are gas-discharge lamps that emit an orange-red glow when an electrical current passes through them. These indicators are the most obvious ones and have a long service life. Neon indicators are usually used in scenarios where high visibility is paramount, such as in the diagrams of control panels, switchboards, and warning systems. Because of their high light intensity, they are also great for outdoor activities and can be seen in different lighting conditions. 4. Digital Panel MetersDigital panel meters are modern-day panel indicators that display numerical or alphanumeric values of various electrical or process parameters on their screens. These meters can show voltage, current, temperature, pressure, and other vital measurements. Digital panel meters usually have programmable settings that let users decide the display range, units, and other specifications needed for their application. Some cutting-edge models might have communication interfaces for logging data or connecting with other systems. Functions and Applications of Panel IndicatorsPanel indicators serve a variety of functions in different applications, including:System Status Indication:The main goal of panel indicators is to reveal a graphical view of a system or part. LED indicators best show the system state, which can be on, in standby mode, or in an error condition.  Warning and Fault Indication:The indicator buttons are usually used to alert the operators or users about possible faults, warnings, or critical situations in the system. Therefore, a red LED indication may indicate a load overload, while a flashing yellow LED may indicate a low battery level. Process Monitoring:In industrial operations, indicators on panels, such as digital panel meters, monitor and display process parameters like temperature, pressure, flow rate, and level. These indicators are the tools the operators use to examine the critical process variables in real time. Therefore, they can make the appropriate decisions and take the necessary actions when the red flags appear. Equipment Diagnostics:These mechanisms define powers and are used for equipment diagnostic and troubleshooting purposes. Technicians can quickly identify problems in components or subsystems by monitoring their conditions. As a result, they can separate the issues, reducing downtime and enabling effective maintenance and repair activities. User Interface and Control:In some cases, panel indicators may be integrated with user interfaces or control systems, showing the system status to the users or acting as input devices for the interaction. A pushbutton indicator that initiates a specific action or sequence within a control system would be a simulation of this kind. Best Practices for Panel Indicator Selection and InstallationWhen selecting and installing panel indicators, it is essential to consider the following best practices: To choose and put into place the panel indicators, the following best practices should be taken into consideration:1.Operating Environment:Consider the job situation where the panel indicators will be applied. For example, temperature, humidity, and vibration affect the indicators, influencing their performance and lifespan. Pick indicators that are specially made for your project's specific environmental conditions.  2.Visibility and Readability: The panel indicators should be visible and readable even from a distance and from the angle of the road. So, consider the indicators' size, brightness, contrast, and lighting for the installation.  3.Panel Layout and Placement: Factors in the operator's daily routine and the level of importance of each indicator should be considered while setting the panel indicators clearly and rationally. The proper panel layout will increase the operator's productivity and reduce the probability of making a mistake.  4.Electrical Compatibility: Check that the panel indicators are as electrically consistent as the system or circuit where they will be installed. This deals with different aspects like voltage, current, and power requirements and the specific electrical standards and regulations that should be adhered to.  5.Mounting and Installation: The manufacturer's instructions should be considered when installing the panel indicators properly. The indicators must be firmly fixed and maintained in the correct orientation. If needed, gaskets or seals should be used to ensure the specified level of ingress protection. Consequently, when you follow these guidelines, you will be sure that the panel indicators in your application are selected and set up correctly. This will ensure that the information you get is accurate and that the system is safe and efficient.  6.Labeling and Documentation: The panels with each color marked should be labeled with the words of their function and the system or the component to which they belong. The author insists on keeping the proper documentation, which entails the wiring diagrams, installation instructions, and troubleshooting procedures for the panel indicators and the whole system.   The above precautions will ensure that the panel indicators in your application are selected and installed correctly, guaranteeing the system's running with accurate and safe information. ConclusionPanel indicators are essential elements of many electrical and electronic systems; they are tools that provide the necessary visual information and control facilities. Understanding different kinds of panel indicators, their functions, and how they are applied will help you select the ones suitable for your specific needs. By using the most efficient methods of picking and installing the panel indicators, you can enhance their efficiency and reliability, thus creating a perfect system performance and user experience. FAQsQ: What are panel indicators and why are they important in industrial automation?A: Panel indicators show the condition of equipment, indicating power status, faults, or operational readiness. They are crucial for maintaining efficient systems. Q: How do I choose the right LED panel indicator?A: Consider energy efficiency, lifespan, and color-coding (e.g., green for operational, red for faults). Q: When should I opt for incandescent indicators instead of LED indicators?A: Choose incandescent indicators for their low cost and simple design when budget constraints are a priority. Q: What are the benefits of using neon indicators in my application?A: Neon indicators offer high visibility and a long service life, ideal for control panels and warning systems. Q: How do digital panel meters differ from traditional panel indicators?A: Digital panel meters display numerical values of parameters like voltage and temperature, with programmable settings and data logging capabilities. Q: What are the best practices for selecting and installing panel indicators?A: Ensure visibility, proper placement, electrical compatibility, and secure mounting. Label indicators clearly and maintain proper documentation.

IntroductionCeramic capacitors are the most used components in the electronics industry, as they are loved for their versatility, reliability, and affordability. However, these components are not limited to such narrow applications, but they play a very important role, from non-critical reductions of noise in consumer electronics to very critical in power supply circuits or communications. This article discusses the fundamentals of ceramic capacitors, their types, and applications, as well as the considerations you must take in mind before using them. Understanding Ceramic CapacitorsCeramic capacitors are passive electronic components made of two conductive plates separated by a dielectric material. The dielectric compound is a ceramic material approached mainly with barium titanate, titanium dioxide or a combination of such and other ceramic products. Through the stuffing in the capacitor, the ceramic material is capable of cyclically attracting and releasing electrical charge, which makes the device work. It consists of repeatedly alternate conductive and dielectric layers, ultimately creating a solid compact structure made of many thin layers. In this way, not only does the construction withstand high values fixed in small areas, but it also achieves the following performance criteria. Types of Ceramic CapacitorsCeramic capacitors are broadly categorized into two main types based on their construction and electrical properties: Multilayer Ceramic Capacitors (MLCCs) and Ceramic Disc Capacitors. Multilayer Ceramic Capacitors (MLCCs): Now, MLCCs are built by the vertical stacking of the ceramic dielectric and metal electrodes, which is repeated thousands of times in a single capacitor. Hence, the capacitors of this design can support high capacitance values in relatively small physical sizes. Accordingly, multilayer ceramic capacitors (MLCCs) are the most popular ceramic capacitors used worldwide in today's electronics industry. Ceramic Disc Capacitors: These supercapacitors involve coating a ceramic disc with two metallic electrodes. While their low capacitance value compared to MLCC (multilayer ceramic capacitor) is their disadvantage, ceramic disc capacitors are still highly prized for their stability and reliability in high-voltage applications. Ceramic Capacitors Dielectric ClassesThe ceramic capacitors' dielectric classes help in selecting the capacitors based on their usage.  Class 1 Ceramic Capacitor DielectricThey offer the ability to achieve the best results regarding stability and output, respectively.These two applications provide low-loss oscillators and filters.It is used for high-tolerance capacitors for its stable temperature coefficient.The ceramic capacitor dielectric can be characterized by three components: temperature coefficient, absolute value of capacitance changes at higher temperatures, and relative permittivity.The number that indicates the amount of multiplication is the second character numeric value.The third character is a letter that exhibits the maximum error in the ppm/C.  Class 2 Ceramic Capacitor DielectricThe capacitance behaves like a variable capacitor whose value is dependent on the applied voltage.Class-2 dielectric materials present with non-linear temperature coefficients.Coupling and decoupling utilize these. They help in the assembly operation.The event is equally drawn from the same three elements. The first parameter is the letter, which indicates the very low temperature of this type.The second element clarifies numerically the highest operating temperature.The third character is a letter, and it depicts capacitance variation with regard to temperature.  Class 3 Ceramic Capacitor DielectricIn addition, the permittivity values of class 3 dielectrics are very high, up to 50000 times higher than those of class 2 dielectrics.They entail heavy losses of current and display voltage-dependent capacitance behaviour.The most important technology that has emerged during a Class 4 Ceramic Capacitor Dielectric is digitalization.They are also known as input capacitors to them. Applications and Uses of Ceramic CapacitorsA Brief Explanation of the Applications and Utility of Ceramic Capacitors The applications of ceramic capacitors include:Transmitter stationsInduction furnacesHigh-power monolithic capacitors.Power circuit breakersHigh-density applicationsPrinted circuit boards These capacitors are additionally rechargeable and are also used as general-purpose capacitors across the brushes of the DC motors in order to suppress the RF noise. Advantages of Ceramic CapacitorsCeramic capacitors offer several advantages that make them a preferred choice in many electronic applications: Compact Size:First of all, ceramic capacitors have a very small footprint compared to other capacitors because of their small size. In contrast to traditional capacitors that have bulky outer cases, these small nano-capacitors have tiny packages. Thus, they can be used for small and cramped spaces and electronic devices with small dimensions. High Reliability:Ceramic capacitors are famous for their extreme reliability and superior solidity. They are characterized by fault-tolerance, which is resistance to climatic conditions, including high temperatures, vibrations, and shock, and they can support applications with heavy loads. Low Inductance:Overall, ceramic capacitors can be appreciated for their large construction, which accounts for low inductance, which is valuable for high-frequency applications and EMI (electromagnetic interference) minimization. Wide Capacitance Range:Ceramic capacitors can be procured in a wide range of values from pico- to microfarads; therefore, designers could select the optimal capacitance for a given circuit by coming for the right capacitance value. Cost-Effective:Ceramic capacitors are definitely a cheaper option than other types of capacitors, specifically for high-volume applications, which has given them the nickname of a pocket-friendly option for many electronics. Selecting the Right Ceramic CapacitorWhen choosing a ceramic capacitor for a particular application, several factors must be considered to ensure optimal performance and reliability: Capacitance Value:The right choice of the capacitance value has a major role in the correct operation of the circuit. The designers should perform careful calculations of the needed capacitance depending on the working frequency, voltage, and other related parameters. Voltage Rating:Capacitors made with ceramic can withstand different voltage ratings, and it is highly important to use one with a higher blocking voltage rating than the circuit's maximum operating voltage to prevent breakdown and maintain circuit safety. Temperature Characteristics:Ceramic capacitors inherently show the different reactions created by the temperature that moves. Choose the proper theses property, for example, for those which are not very much affected by wide workman's temperature.Mounting Style:Given the application, designers should understand both types of mounting methods well and make a final selection between surface mount and through-hole, considering that there are board space, assembly process, and environmental influences issues. Dielectric Material:Generally, the capacitance of ceramic capacitors depends on the dielectric material. A capacitor is also affected by resistance to current flow (power factor or dissipation factor) and how stable its structure is in the long run (dielectric stabilization). Particularly critical in selecting the dielectric material is achieving all the desired application requirements. Considering these factors and communicating with capacitor manufacturers or technical advice are important steps for the design of the circuits where the ceramic capacitors are supposed to be embedded, making such an effort will ensure the best application of such capacitors in electronics. Proper Installation and HandlingThe right method is a must for the installation and handling of ceramic capacitors for good results and increasing lifespan. The correct board layout, component placement, and soldering ensure that physical stress is kept at a minimum and avoid any possible failures. Furthermore, taking actions such as electrostatic discharge (ESD) protection measures during assembly and handling must be the preventive measure to keep these components from damage. ConclusionIn conclusion, ceramic capacitors are not replaceable in the electronic devices industry because of their efficient combination of characteristics such as working range, reliability, and prices. Their generic system capabilities are used for all kinds of applications, from as simple as noise reduction to the more critical roles of ensuring safety and communication systems. Discovering and knowing the kinds, areas of utilization, and rules that can be faced in the use of ceramic capacitors can help engineers and designers make the best use of them for their particular circuits that prioritize stability, efficiency, and cost-reduction in their designs.

Introduction Automotive connectors are a component that very common for electronic engineering technicians. Its function is very simple: it sets up a bridge of communication between the blocked or isolated circuits in the circuit, so that the current flows and the circuit realizes the predetermined function. The form and structure of automotive connectors are ever-changing. They are mainly composed of four basic structural components, namely: contacts, shells (depending on the types), insulators, and accessories. Common Automotive Electrical Connections Catalog Introduction Ⅰ Automotive Connectors Ⅱ Basic Structure Ⅲ Design Criteria Ⅳ Automotive Connector Development Trends Ⅴ Connector Selection Ⅵ Performance Standard for Automotive Electrical Connectors Ⅶ FAQ Ⅰ Automotive Connectors There are nearly 100 types of connectors used in general automobiles, and there are hundreds of connectors used in a single model. As people have higher and higher requirements for safety, environmental protection, comfort, and intelligence in automobiles, the application of automotive electronic products is increasing, which make the number of automotive connector applications increase. Figure 1. Automotive Connector Type Ⅱ Basic Structure The four basic structural components of automotive connectors, it is these four basic structural components that enable automotive connectors to act as a bridge to make cars run stably.First, the contact piece is the core part of the automobile connector to complete the electrical connection function. Generally, a contact pair is composed of a male contact piece and a female contact piece, because the electrical connection is completed by the insertion of two parts.The male contact is a rigid part, and its shape is cylindrical (round pin), square column (square pin) or flat (insert). The male contacts are generally made of brass and phosphor bronze. The female contact piece is the jack, which is the key part of the contact pair. It relies on the elastic structure to elastically deform when it is inserted into the pin to generate elastic force to form close contact with the male contact piece to complete the connection. There are many types of jack structures, including cylindrical type (split slot, necking), tuning fork type, cantilever beam type (longitudinal slotting), folding type (longitudinal slotting), box type (square jack) and hyperboloid wire spring jacks, etc.Second, the shell, is the outer cover of the automotive connector. It provides mechanical protection for the built-in insulating mounting plate and pins, and provides alignment when the plug and socket are inserted, thereby fixing the connector to the device.Third, insulators, are also often referred to as automobile connector bases or inserts. Its function is to arrange the contacts according to the required position and spacing, and to ensure the insulation performance with the shell. Good insulation resistance, withstand voltage performance and ease of processing are the basic requirements for selecting insulating materials to be processed into insulators.Fourth, accessories, are divided into the structural part and the installation part. Structural accessories such as retaining rings, positioning keys, positioning pins, guide pins, coupling rings, cable clamps, sealing rings, gaskets, etc. Mounting accessories such as screws, nuts, spring rings, etc. Most of the accessories have standard parts and general parts.   Ⅲ Design Criteria With the rapid development of the automobile industry, various functional parts and various components on the automobile are constantly developing in the direction of intelligence, refinement and reliability. The structural design, appearance design and material of automobile connectors are also proposed. higher requirement. Automotive connectors must meet the USCAR-20 standard, which is the performance standard of automotive electrical connector systems. It is necessary to stipulate that the electrical connector contact surface of automotive connectors should always be reliable throughout the service cycle, including the following factors:1) The material of the connector contacts is stable and reliable.2) Positive force stability.3) The voltage and current of the circuit are stable.4) The temperature requirements are within the specified range, including the surrounding temperature and its own temperature rise.5) Better robustness.6) It must be the same as the connector used for high-speed and long-distance communication computers, and the automotive connector must be able to work reliably under harsh conditions.7) Connector insertion force: below 20.5kg8) Connector retention force: 2.5kg or more9) Heat resistance: -40~120℃ Figure 2. Automotive Connectors Ⅳ Automotive Connector Development Trends The "Miniaturization", "High Speed" and "Intelligence" of connector products are the trends of future development. The future technological innovation of the industry is mainly concentrated in the following directions:1) Miniaturization DevelopmentThis technology is mainly developed for the miniaturization trend of connectors, and can be applied to micro-miniature connectors below 0.3mm, which belongs to the new varieties of MINI USB series products. It can be used for multi-contact expansion card slot connectors, which can meet and exceed the strict requirements of multi-contact surface mount technology butt joint coplanarity, with high accuracy and low cost.2) Wireless TransmissionThe high-frequency and high-speed wireless transmission of connector technology is mainly aimed at a variety of wireless device communication applications and has a wide range of applications.3) Simulation Application TechnologyIt is based on a variety of disciplines and theories, using computer and its corresponding software such as AutoCAD, Pro/E program stress analysis software as tools, through the establishment of product models and corresponding boundary conditions, to its mechanical, electrical, high-frequency simulation analysis and confirmation of other performances, thereby reducing the cost of product development failure caused by factors such as material selection and unreasonable structure, improving the development success rate, and helping to provide support for the realization of complex system applications for products.4) Connector Intelligence TechnologyThis technology is currently mainly used in DC series power connector products. Intelligent signal detection can be performed before power transmission to ensure that the positive and negative poles are turned on and the power is turned on after the plug is inserted in place. In the future, enterprises will need to develop similar intelligent technologies for other products because of the adverse consequences of arc damage and burn-in caused by conductive contact.5) Precision connector technologyPrecision connectors involve many aspects such as product design, process technology and quality control technology. The main technologies include the following aspects:a. Precision mold processing technology: Adopt CAD, CAM and other technologies, introduce high-precision processing equipment in the industry, and use personnel production experience and advanced equipment and technical means to achieve high-precision high-quality mold products.b. Precision stamping and injection molding technology: realize precise, efficient and stable all-round control and perfect surface quality of various stamping parts and injection molding parts to ensure product quality.c. Automated assembly technology: Through the application of precision control technology, semi-automatic testing machine technology, etc., the problem of manual operation of precision products is overcome and the core competitiveness is improved.6) Manufacturing Process ResearchThe competitiveness of products depends to a certain extent on the level of manufacturing technology. Continuously developing new manufacturing processes and improving existing production and processing technologies can greatly improve the manufacturing efficiency and quality assurance capabilities of products.a. Fine manufacturing process: This process is mainly aimed at technologies such as small spacing and thin thickness. Some companies have carried out research on the process of connectors with a spacing of less than 0.4mm. This type of technology can ensure that the company reaches the advanced level of the international industry in the field of ultra-fine manufacturing.b. Integrate development technology of light source signal and electromechanical structure. It can be applied to audio connectors placed in electronic components. By adding IC, LED and other electronic components to the audio connectors, which can also transmit analog signals and the function of digital signal. It breaks through the current design of audio connector conduction transmission in the form of mechanical contact.c. Low temperature and low pressure molding process technology. The sealing and physical and chemical properties of the hot-melt material are used to achieve the functions of insulation and temperature resistance. After packaging, the wire protects the welding point from being pulled by external forces, and the packaging of the DC connector body and the wire has a insulation, temperature resistance, impact resistance and other functions ensure product quality and reliability, and will continue to be developed and applied in different products in the future. Figure 3. Automotive Connectors Ⅴ Connector Selection 1) Electrical FactorCurrent requirements: high current, low current, signal level; Steady state, cyclic, transient.They determine the type of terminal/size of contact segment/plating (0.64mm to 8.0mm pin and male terminal).Wire diameter/insulation requirements: voltage drop and/or corrosion resistance, which determine the center distance of the connector.2) Location/EnvironmentTemperature: Engine compartment – sealed, ambient temperature >105℃; vibration, fluid compatibility, passenger compartment – unsealed, ambient temperature <85℃.Sealing: Potential for high pressure jet/splash, potential for immersion, humidity; fluid type, sealed or not for device connectors.3) StandardStandards: Customer StandardsInstitutional StandardsDomestic StandardsInternational StandardsConnector performance test requirements are included in system-level specifications. For GM, Ford and Chrysler are usually USCAR specifications, that is, engine-related applications have relatively high vibration requirements. Other OEMs generally have their own standards (similar to USCAR). What’s more, equipment-side suppliers are responsible for the performance of mating-side connectors.4) Customer PreferencePreferred product strategy: Reduce cost of connector systems with different methods:Ford: Design competition for door connectors.Ford: Prefer terminal design/supplier (focus on contact interface).General: Prefer the terminal design (focus on the hole position of the connector).Chrysler: Strategies for favoring terminal/plastic Part suppliers.5) Regional preferenceNorth America: USCAR Drawing/Performance/Design Criteria —Tangless Terminals, TPA, CPA regulations. In many instances the harness supplier has a significant influence.Europe: Design influence of contact contacts/development with major OEMs; preference for two-piece contacts, even if cost pressures and North American porting operations force OEMs to consider U.S technology, that is, accepting Tangled contacts. Long-term relationships between OEMs and suppliers.Asia: Traditionally influenced by Toyota. Focus on assembly ability (ergonomics) that affects quality assurance; North America influences China to change the status, like low-cost solutions.6) Physical factorsSize, number of circuits, mating position, wire harness docking or equipment connection, mechanical main features: levers, bolts; manual docking capability; multiple types of connectors for high input/output applications.7) AssemblyWire Harness: Insertion force of connectorVisual, audible and tactile operational feedback for users. Figure 4. Terminals & Connectors Ⅵ Performance Standard for Automotive Electrical Connectors For a connector, the specification parameters such as the ambient temperature, current carrying capacity, protection level, anti-vibration level, etc. will be defined in its specifications at the beginning of research and development, because when the connector is selected according to different requirements. The following are three most widely used standards USCAR-2-6, QC/T1067-2017 and GMW3191-2012.🔺QC/T-1067 Temperature Classification Class Ambient Operating Temperature Typical Installation Position A -40~85℃ Passenger compartment (Not recommended) B -40~100℃ Passenger compartment C -40~125℃ On engine D -40~150℃ On engine (hot locations) E -40~175℃ and above Negotiate   🔺QC/T-1067 Vibration Classification Class Typical Installation Position V1 On elastic parts of the body but not to the engine V2 On engine but not to heavily vibrating parts V3 Components subject to serve vibration V4 Components subject to extreme vibration V5 On Wheel   🔺QC/T-1067 Sealing Classification Class Description Typical Installation Position S1 Unsealed Passenger compartment or trunk S2 Sealed Exposed areas S3 Sealed (with high pressure spray) Exposed areas (with high pressure spray)   🔶GMW-3191 Temperature Class Class Ambient Operating Temperature Typical Installation Position 1 -40~85℃ Passenger compartment or trunk 2 -40~100℃ Underhood, chassis 3 -40~125℃ On engine, transmission 4 -40~150℃ On engine (hot locations) 5 Per connector CTS Per CTS GTS=Component Technical Specification   🔶GMW-3191 Vibration Class Class Typical Installation Position 1 On body or chassis 2 On engine 3 On wheel, Unsprung Mass 4 Severe applications (e.g., ECU, Throttle Body, EGR) 5 Transmission (internal and external) ECU=Engine Control Unit, EGR=Exhaust Gas Recirculation   🔶GMW-3191 Sealing Class Class Description Typical Installation Position 1 Unsealed Unsealed Passenger Compartment or trunk 2 Submersion Sealed Underhood or exposed areas, including door 3 High Pressure Spray Protected Exposed areas where high pressure spray is expected   🔻USCAR-2 Temperature Classification Class Ambient Operating Temperature Typical Application T1 -40~85℃ T1 is not recommended for new applications T2 -40~100℃ Typical suitable for use in passenger component T3 -40~125℃ Typical suitable for use in engine component T4 -40~150℃ Needed for some on-engine applications near hot components T5 -40~175℃ For use as needed   🔻USCAR-2 Vibration Classification Class Common Name Typical Application Other Requirements Met V1 Chassis Profile Components on sprung portions of vehiele not coupled to Engine None V2 Engine Profile Components coupled to Engine with no severe vibration possible Pass on V2 - pass also for V1 V3 Severe On-Engine Components subject to serve vibration Pass on V3 - pass also for V1 and V2 V4 Extreme Vibration Used as needed to correlate to extreme vibration areas Pass on V4 - pass also for V1 and V2 and V3 V5 Unsprung Component Wheel-mounted components None   🔻USCAR-2 Sealing Classification Seal Class Common Name Typical Application S1 Unsealed S1 is suitable for use in passenger components or other dry areas on a vehicle such as the trunk S2 Sealed S2 (meets requirements of 5.9.7) is for exposed locations S3 Sealed (with high pressure spray) S3 is for exposed locations. It meets Sections 5.9.7 plus 5.6.7; S3 is applications when robustness to direct splash is needed Regarding the vibration test, the main purpose is to check whether the performance of the connector system under the simulated actual vehicle vibration conditions meets the requirements. In the case of vibration or in shock, it will cause the coating wear of the terminal contact surface, the positive pressure attenuation, the failure of the mechanical system performance of the supporting plastic material, etc. Therefore, it is necessary to continuously monitor the contact resistance in the vibration experiment and ensure that it does not exceed 7Ω (or 1Ω) in the line for more than 1 microsecond. According to the definition and analysis of the connector using environment through the above different standards, it is necessary to understand that the use position, the temperature level, vibration level, and protection level should be considered to make the best choice.   Ⅶ FAQ 1. What are connectors in cars?Connectors used in automotive applications enable everything from stereo systems to drivetrains. As these systems become more connected, more automated, and more energy-efficient, they require connectors that can deliver high-speed connectivity in rugged, lightweight, and easy-to-install designs. 2. How do I choose a car connector?There are several criteria to consider when selecting electrical interconnect components, including:Current rating (current density)Connector size (circuit density)Engagement forceWire sizeConfiguration and circuit sizeOperating voltageAgency approvalsPrice per circuit 3. What are the different types of automotive electrical connectors?Automotive TerminalsContactsCrimp Wire Pins, Tabs & FerrulesFoil TerminalsInterconnect DevicesKnife DisconnectsMagnet Wire TerminalsPCB Terminals 4. How many connectors does a car have?Today, there are an average of 274 connectors in a vehicle. 5. Are all car stereo connectors the same?All aftermarket car stereos can use the same car stereo wiring harness, but it all depends on what the owner of the vehicle wants to do for one main reason. 6. What is uscar standard?SAE USCAR-2. May 1, 2004. PERFORMANCE STANDARD FOR AUTOMOTIVE ELECTRICAL CONNECTOR SYSTEMS. Procedures included within this specification are intended to cover performance testing at all phases of development, production, and field analysis of electrical terminals, connectors, and so on.

IntroductionA transformer is a passive electrical device that transfers electrical energy from one electrical circuit to another, or multiple circuits. Its transmission current is AC. Transformer is commonly used to increase or decrease the supply. As one of the types, high-frequency transformers use frequencies from 20 KHz to over 1MHz. This paper tells the design process of high-frequency transformers (HFTs), that is, how to calculate high frequency transformer?How to Make High Frequency Transformer?CatalogIntroductionⅠ Transformer Core1.1 Magnetic Core Material1.2 Core Structure1.3 Core Parameters1.4 Coil Parameters1.5 Coil Turns1.6 Assembly Structure1.7 Temperature Rise CheckⅡ Types of High Frequency Transformer2.1 Transformer Classifications2.2 Design RulesⅢ Transformer Core Selection CaresⅣ Main Transformer ParametersⅤ How to Calculate High Frequency Transformer?5.1 Design Principles and Methods of Transformers5.2 AP Method Analysis5.3 Parameters of Power Supply5.4 Transformer Turns CalculationⅠ Transformer CoreIn real transformers, the two coils are wound onto the same iron core. The transformer core provides a magnetic path to channel flux. The use of highly permeable material (which describes the material's ability to carry flux), as well as better core construction techniques, helps provide a desirable, low reluctance flux path and confine lines of flux to the core. The following introduces some important aspect of the transformer core.1.1 Magnetic Core MaterialWhich material is best for high frequency transformer core? Soft ferrite is widely used in switching power supply due to its own characteristics. Its advantages are high resistivity, low AC eddy current loss, low price, and easy processing into various shapes. It also has disadvantages, including low working magnetic flux density, low permeability, large magnetostriction, and relatively sensitive to temperature changes. Choosing suitable materials can fully meet the design requirements of high-frequency transformers, and they have ideal performance and price advantage.1.2 Core StructureTransformer core as a main part, the factors to be considered when selecting the magnetic core structure are: reducing magnetic leakage and leakage inductance, increasing the heat dissipation spacing of the coil, which is beneficial to shielding, easy coil winding, and convenient assembly and wiring. Magnetic leakage and leakage inductance are directly related to the core structure. If the magnetic core does not require an air gap, a closed ring-shaped or square-shaped magnetic core is better.1.3 Core ParametersIn the design of the magnetic core parameters, special attention should be paid to the magnetic flux density on working not only limited by the magnetization curve, but also by the loss, and the working mode of power transmission. When the magnetic flux changes in one direction: ΔB=Bs-Br, which is not merely limited by the saturation magnetic flux density, but also mainly by the loss, (the loss causes a temperature rise to affect the magnetic flux density). Working magnetic flux density Bm=0.6～0.7ΔB.Opening the air gap can reduce Br to increase the magnetic flux density change value ΔB. After then, the excitation current increases, but the magnetic core volume can be reduced. For magnetic flux work in two-way: ΔB=2Bm. In this case, it is also necessary to pay attention to the fact that the volt-second area of the positive and negative changes of the excitation is not equal due to various reasons, and the DC bias problem occurs. Therefore, a small air gap can be added to the magnetic core, or a DC blocking capacitor can be added in the circuit design.1.4 Coil ParametersCoil parameters include the number of turns, wire section (diameter), wire form, winding arrangement and insulation arrangement.The wire diameter is determined by the current density of the winding. Usually J is 2.5～4A/mm2. The choice of wire diameter should consider the skin effect. If necessary, make adjustments after checking the temperature rise of the transformer.1.5 Coil TurnsGenerally used winding arrangement: The primary winding is close to the magnetic core, and the secondary winding feedback winding is gradually arranged outward. Two winding arrangements are recommended as following:1) If the voltage of the primary winding is high, and the secondary winding voltage is low, the secondary winding can be used close to the magnetic core, and next is the feedback winding, and the primary winding is in the outermost, which is beneficial to the primary winding to the magnetic core. Insulation arrangement.2) To increase the coupling between the primary and secondary windings, half of the primary windings can be close to the core, then the feedback winding and secondary windings, and another half primary windings in the outermost layer, which will reduce leakage inductance helpfully.1.6 Assembly StructureThe assembly structure of a high-frequency power transformer is divided into two types: horizontal and vertical. If using plane magnetic cores, chip magnetic cores and thin film magnetic cores, they all adopt a horizontal assembly structure.1.7 Temperature Rise CheckThe temperature rise check can be carried out by calculation and sample testing. The experimental temperature rise is lower than the allowable temperature rise by more than 15 degrees, increasing the current density and reducing the wire section appropriately. If it exceeds the allowable temperature rise, appropriately reduce the current density and increase the wire section. For example, increase the heat dissipation area of the magnetic core and wire diameter.Transformer SymbolⅡ Types of High Frequency Transformer2.1 Transformer ClassificationsPower transformers are divided into three categories according to the topology:(1) Flyback transformer(2) Forward transformer(3) Push-pull transformer (in full-bridge/half-bridge)The suitable topological structure of the magnetic core structure is shown in the table on the following:Core StructureTransformer Circuit TypeFlyback TypeForward TypePush-pull TypeE cores++0Planar E Cores-+0EFD Cores-++ETD Cores0++ER Cores0++U Cores+00RM Cores0+0EP Cores-+0P Cores-+0Ring Cores-++Remarks: "+"=Appropriate   "0"=Normal   "-"=None2.2 Design Rules1) If the DC filter inductor, and the inductor core only works in one quadrant, the inductors belonging to this type include Boost inductors, Buck inductors, Buck/boost inductors, forward and push-pull transformer filtering inductors, and single-ended transformers.2) The magnetic core of the forward transformer only works in one quadrant, so the transformer needs to be magnetically reset.3) The magnetic core of the push-pull transformer is bidirectional alternating magnetization. Converters belonging to this category include push-pull converters, half-bridge and full-bridge converters, and AC filter inductors. Ⅲ Transformer Core Selection Cares1) Soft ferrite is widely used in switching power supply due to its low price, good adaptability and high frequency performance.2) Soft ferrites are common in two series: manganese-zinc ferrite and nickel-zinc ferrite. The components of manganese-zinc ferrite are Fe2O3, MnCO3, and ZnO. It is mainly used in various filters below 1MHz, inductors, transformers, etc., with a wide range of applications. The components of nickel-zinc ferrite are Fe2O3, NiO, ZnO, etc., which are mainly used for various induction windings above 1MHz, anti-interference magnetic beads, and sharing antenna matching devices.3) Manganese-zinc ferrite cores are the most widely used in switching power supplies. Depending on their use, the choice of materials is also different. The cores used in the power input filter part are mostly high-permeability, and their material grades are mostly R4K～R10K, that is, ferrite cores with a relative permeability of 4000～10000. For main transformers and output filters, most of them have high saturation magnetic flux density, and their Bs is about 0.5T (ie 5000GS). Ⅳ Main Transformer Parametersa.Transformer TopologyWith a higher saturation magnetic flux density Bs and a lower residual magnetic flux density Br,  Bs has a certain impact on the transformer and winding results. Theoretically, if Bs is high, the number of winding turns will decrease, and the copper loss will also decrease. In practical applications, there are many circuit forms of switching power supply high-frequency converters. For transformers, their working forms can be divided into two categories:BipolarThe circuit is half-bridge, full-bridge, push-pull, etc. The positive and negative half-cycle excitation currents in the transformer primary winding are identical in magnitude and opposite in direction. Therefore, the magnetic flux changes in the transformer core also move symmetrically up and down. Maximum change range of B is △B=2Bm, and the DC component in the core basically cancels out.UnipolarThe circuit is single-ended forward, single-ended flyback, etc. The primary winding of the transformer adds a unidirectional square wave pulse voltage in one cycle (single-ended flyback is the case). The transformer core is unidirectionally excited, and the magnetic flux density varies from the maximum value Bm to the residual magnetic flux density Br. At this time, △B=Bm－Br. If Br is reduced and the saturation magnetic flux density Bs is increased, △B can be increased. It can reduce the number of turns and the copper loss. b. Low Power Loss at High FrequenciesThe power loss of ferrite not only affects the output efficiency of the power supply, but also causes the core heating, waveform distortion and other undesirable consequences. The heating problem of the transformer is extremely common in practical applications. It is mainly caused by the copper loss and core loss. If Bm is selected too low when designing the transformer, and more winding turns will cause the winding to heat up, and at the same time transfer heat to the magnetic core. Conversely, if the core is the main heating body, it will also cause the winding to heat up.When selecting ferrite materials, the power loss is required to have a negative temperature coefficient relationship. If the core loss is the main body of heat, the temperature of the transformer will rise, which will cause the core loss to increase further, eventually burn out the power tube, transformer and other components. Therefore, when developing power ferrites at home and abroad, it is necessary to solve the problem of the negative temperature coefficient of the magnetic material itself. This is also a significant feature of the magnetic material for power supply. c. PermeabilityHow much is the appropriate permeability? This should be determined according to the switching frequency of the actual circuit. Generally, materials with a relative permeability of 2000 have an applicable frequency below 300kHz, and sometimes it can be higher, less than 500kHz. For materials higher than this value, a lower magnetic permeability should be selected, generally around 1300. d. Higher Curie TemperatureThe Curie temperature is the temperature at which the magnetic material loses its magnetic properties, general above 200℃. However, the actual working temperature of the transformer should not be higher than 80℃. This is because when the temperature is above 100℃, its saturation magnetic flux density Bs has dropped to 70% of that at room temperature. Therefore, an excessively high operating temperature will cause the saturation flux density of the magnetic core to drop more severely. Furthermore, when it is higher than 100°C, its power consumption has a positive temperature coefficient, which will lead to a vicious circle. For the R2KB2 material, the temperature corresponding to its allowable power consumption has reached 110°C, and the Curie temperature is as high as 240°C, which meets the requirements for high-temperature use. Ⅴ How to Calculate High Frequency Transformer?5.1 Design Principles and Methods of TransformersThere are two principle methods for designing transformers: area product AP method. AP is the product of the core cross-sectional area Ae and the coil effective window area Aw.PT-power of transformerAe- effective cross-sectional areaAw- core window areaKo-core window utilization factor, typical value is 0.4.Kf-form factor, square wave is 4, and sine wave is 4.44.Bw-the working magnetic intensity of the magnetic coreFs-switch operating frequencyKj-current density coefficient, take 395A/cm2X-core structure coefficient5.2 AP Method AnalysisAccording to the design method of power transformer, the general steps of designing transformer with area product AP method:1. Select the core material and calculate the apparent power of the transformer.2. Determine the core cross-sectional size AP, and then select the core size according to it.3. Calculate the inductance and number of turns of the primary and secondary sides.4. Calculate the length of the air gap.5. Find the wire diameter according to the current density and the effective value current of the primary and secondary sides.6. Determine whether the copper loss and iron loss meet the requirements (allowable loss and temperature rise).5.3 Parameters of Power SupplyInput voltage: 175-264VACOutput voltage: 21VOutput power: 3AThe frequency is set at 60KHz, and the duty cycle is initially set at 0.45. Using a flyback topology, choose the core material and determine the apparent power PT of the transformer.Consider the cost, choose PC40 material here:Check the PC40 data and get Bs=0.39T, Br=0.06TBm= ΔBmax*0.6=0.198T, round it to 0.2TIn order to prevent the magnetic core from being saturated momentarily, reserve a certain margin and take Bm= ΔBmax*0.6=0.198T, take 0.2T.Transformer apparent power PT, for the flyback transformer:Calculate AP:Where:J is the current density, usually taking 395A/cm2.Ku is the effective use coefficient of the copper window, which is determined according to the safety requirements and the number of output channels, generally 0.2 to 0.4. Take 0.4 here to adapt to the sudden load current. The power supply is designed in critical mode, and the critical current I0B=0.8×I0=2.4A5.4 Transformer Turns Calculation1) Minimum input voltage: Vimin=ViACmin*1.2=210V2) Turns Ration=[Vimin/(Vo+Vf)]*[Dmax/(1-Dmax)]n=[210V/(21V+1V)]*[0.45/(1-0.45)]=7.83) Secondary Side Peak Current^IsB=2*IoB/(1-Dmax)^IsB=2*2.4A/(1-0.45)=8.72A4) Secondary Side InductanceLs=(Vo+Vf)*(1-Dmax)*[1/(Fs*1000)]/^IsB*1000000Ls=(21V+1V)*(1-0.45)*[1/(60KHz*1000)]/^8.72A*1000000=23.58uH5) Primary Side InductanceLp=n*n*LsLp=7.8*7.8*23.58uH=1434uH6) Secondary Side Peak Current (continuous mode)^IsB=Io/(1-Dmax)+(^IsB/2)^IsB=3A/(1-0.45)+(8.72A/2)=9.81A7) Primary Side Peak Current (continuous mode)^Ipp=^Isp/n^Ipp=9.81A/7.8=1.257APrimary Winding and Secondary Winding Turns1) Primary Winding TurnsNp=Lp*^Ipp(^B*Ae)Np=1434uH*1.257A/(0.2*84.8)=106.28T，round it to 106T2) Secondary Winding TurnsNs=Np/nNs=106T/7.8=13.58T，round it to Ns=14T3) Feedback TurnsNv=(Vcc+Vf)/[(Vo+Vf)/Ns]Nv=(14.5V+1V)/[(21V+1V)/14T]=9.87T, round it to Nv=10TIn order to avoid saturation of the magnetic core, an appropriate air gap is added to the magnetic circuit, and the calculation is as follows:It may be necessary to correct the number of turns based on the edge effect of the air gap flux.There are two methods for the wire diameter of the primary, secondary and auxiliary windings:Bare wire areaPrimary Winding diameter: effective currentIprms=Po/^n/ViminIprms=63W/0.8/210V=0.375AWire diameter (J current density is 4A/mm2)Use two 0.18mm diameter wires and wind them together, or use AWG #28 single stranded wire.Secondary winding diameterUse 4 wires with a diameter of 0.25mm to be wound in parallel and calculate the current skin depth:The wire diameter of multiple strands must be less than or equal to dwH. For single wire winding, if the wire diameter exceeds the dwH, it is necessary to consider the use of multiple strands.The calculation of copper loss Pcu and iron loss Pfe (transformer total loss Ploss)a) Primary winding and secondary winding losses. Among them, MLT is the average turn length of the magnetic core. b) Calculate the allowable total loss Ploss and iron loss under the efficiency η.c) Find the actual loss under the operation according to the core loss curve.Iron loss per unit weight, it actually occurredThe actual iron loss should be lower than the allowable value.d) Calculate the loss per unit area Φ=Ploss/As. If the temperature rise caused by the Φ value is less than 25 degrees, the design is good.Bw Calculation:The working magnetic flux density Bw should be met the design index requirements, Bw<Bs-Br, to avoid saturation of the magnetic core. Frequently Asked Questions about High Frequency Transformer Design1. What is high frequency transformer?The primary difference is that, as their name implies, they operate at much higher frequencies — while most line voltage transformers operate at 50 or 60 Hz, high-frequency transformers use frequencies from 20 KHz to over 1MHz. ... For any given power rating, the higher the frequency, the smaller the transformer can be. 2. What are the design aspects of high frequency transformer?Design of HF transformers. High frequency transformers transfer electric power. The physical size is dependent on the power to be transfered as well as the operating frequency. The higher the frequency the smaller the physical size. 3. What is the use of high frequency transformer?These transformers are designed to handle up to 15,000 volts safely and accurately, converting high voltage and current levels between coils by magnetic induction. High Voltage, High Frequency Transformers are relied on for applications ranging from power supplies to laser equipment and particle accelerators. 4. What is difference between high frequency and low frequency?When we talk about sound, we talk in terms of high and low-frequency waves. ... This measurement of cycles per second is expressed in Hertz (Hz), with a higher Hz representing higher frequency sound. Low-frequency sounds are 500 Hz or lower while high-frequency waves are above 2000 Hz. 5. What is the frequency of transformer?What is Transformer Frequency. The three common frequencies available are 50Hz, 60Hz and 400Hz. European power is typically 50Hz while North American power is usually 60hz. The 400 Hz is reserved for high-powered applications such as aerospace and some special-purpose computer power supplies and hand-held machine tools.

Ⅰ IntroductionFlyback Diodes, which are also known as freewheeling diodes, generally refer to diodes that are inversely paralleled across the ends of energy storage elements such as inductors, relays, and thyristors. When a voltage or current changes suddenly in a circuit, it protects other components in the circuit. When using a flyback diode, the circuit current can be changed more gently to avoid the occurrence of voltage spike. This article will introduce in detail what is flyback diode, how freewheeling diode works, flyback diode selection and the flyback diode function.How Freewheeling Diode WorksCatalogⅠ IntroductionⅡ DesignⅢ How It Works?Ⅳ SelectionⅤ Applications5.1 Summary5.2 In Forward Switching Power Supply5.3 In Converter Technology5.4 In Unidirectional Half Wave Silicon Control Rectifier Circuit5.5 In BUCK CircuitⅥ Something Has to CareIn electronics, a flyback voltage or an inductive flyback is a voltage spike created by an Inductor when its power supply is removed abruptly. The reason for this voltage spike is the fact that there cannot be an instant change to the current flowing through an Inductor.In addition, time constant of the inductor determines the rate at which the current can change through an inductor. This is similar to the time constant of a capacitor, which determines the rate at which its voltage can change.The freewheeling diode is named because it plays the role of freewheeling in the circuit. It is generally used in the circuit to protect components from being damaged or burned out by voltage breakdown, connected in parallel to both ends of the elements that generate the induced electromotive force(EMF), and form a loop with them, so that the high electromotive force generated in the loop is consumed by the continuous current method, thereby protecting the components in the circuits.Flyback diodes are connected in parallel at both ends of the coil. When the current passes through the coil, it will generate induced electromotive force at both ends. When the current disappears, its induced electromotive force generates a reverse voltage to the components in the circuit. When the reverse voltage is higher than the reverse breakdown voltage of the elements, it will cause damage to the elements such as triode and thyristor. When the current flowing through the coil disappears, the induced electromotive force generated by the coil is consumed by the work formed by the diode and the coil, thereby protecting the other elements in the circuit.Ⅱ DesignIn the following figure, it is showed that a flyback diode is placed across the inductor. An ideal flyback diode will have a very large peak forward current; capacity which helps in handling the voltage transients from damaging the diode, and inductor’s power supply is suited for reverse breakdown voltage and low forward voltage drop. Voltage spike can be 10times to the voltage of power supply which depends on the equipment involved and the application. So it is understood that not to underestimate the energy which contain within an energized inductor. Figure 1. Flyback DiodeFor an ideal flyback diode selection, a diode which has very large peak forward current capacity (to handle voltage transients without burning out the diode) should be selected, moreover, low forward voltage drop, and a reverse breakdown voltage fitted the inductor's power supply. Depending on the application and equipment in real requirement, some voltage surges can be upwards of 10 times the voltage of the power source, so it is critical not to underestimate the energy contained within an energized inductor.Flyback Diode Selection Note You Should KnowWhen used with a DC coil relay, a flyback diode can cause delayed drop-out of the contacts when power is turned off, due to the continued circulation of current in the relay coil and diode. When rapid opening of the contacts is important, a small value resistor can be placed in series with the diode to help dissipate the coil energy faster, at the expense of higher voltage at the switch.Schottky diodes are preferred in flyback diode applications as switching power converters, because they have the lowest forward drop (~0.2V rather than >0.7V for low currents) and are able to quickly respond to reverse bias (when the inductor is being re-energized). They therefore dissipate less energy while transferring energy from the inductor to a capacitor.When the flyback diode is used to simply dissipate the inductive energy, as with a solenoid or electric motor, cheap 1N540x and 1N400x general-purpose diodes are used instead. Ⅲ How It Works?Flyback diodes are often used with energy storage elements to prevent sudden changes in voltage and current to provide a pathway. The inductor can provide continuous current to the load through it to avoid sudden changes in load current and smooth the current. In the switching power supply, you can see a freewheeling circuit composed of a diode and a resistor connected in series, which is connected in parallel with the primary side of the transformer. When the switch is turned off, the freewheeling circuit can release the energy stored in the transformer coil to prevent the induced voltage from being too large and breakdown the switch. Generally, it is often to choose the fast recovery diode or the Schottky diode as flyback diode.Circuit Expressions Figure 2. Flyback Diode in Switching Power Supply CircuitIn Figure 2(c), when KR is turned on, the upper is positive voltage and the lower is negative voltage,  and the current direction is from top to bottom. When the VT is turned off, the current in the KR is suddenly interrupted and an induced potential is generated. The current direction is kept constant, that is, keeping the KR current direction from the top to bottom, which based on the Lenz's law. The induced potential and the power supply voltage are superimposed and applied across the VT, making it easy for the VT to breakdown. To avoid it, VD is used to short-circuit the induced potential generated by KR, that is, The current flows clockwise in the small circuits of the diodes and relays to protect the VT. R and C in Figure 2(b) also use the principle that the voltage on C cannot be abruptly changed to absorb the induced potential.In short, the flyback diode is connected in parallel to the relay or the inductor at both ends of the circuit. When the inductor is powered off, the electromotive force at both ends does not disappear immediately. At this time, the residual electromotive force is released through a freewheeling diode to reverse the reverse generated by the coil (the EMF is consumed in the form of current). It can be seen that the freewheeling diode is not a substantial component, but plays a "freewheeling" role in the circuit.For example, reversely connect a flyback diode at both ends of a relay coil or at both ends of a unidirectional thyristor. In practice, electromagnetic relays are usually controlled by triodes or MOS tubes to achieve automatic control of electrical loads (such as through a single-chip microcomputer), and the coil of the relay is a large inductance, which can store electrical energy in the form of a magnetic field. So when it pulls in, it stores a lot of magnetic field. When the triode controlling the relay changes from on to off, the coil is powered off, but there is a magnetic field in the coil. At this time, the back electromotive voltage can be as high as 1000v to destroy other circuit components. This is because the access of the diode is exactly the same as the direction of the reverse electromotive force. So that the reverse potential is neutralized by the freewheeling diode in the form of current to protect other circuit components. In addition, it is generally a diode with a fast switching speed.  Figure 3. Freewheeling Diode CircuitBecause the relay coil exists inductive load, which will absorb the self-inductive voltage of the relay coil when the triode is turned off. According to Lenz's law, when the current on the inductor decreases, a self-inductive voltage is generated. The direction of this voltage is that the forward terminal is negative and the collector of the driving tube is positive. This voltage will break through the triode, so an freewheeling diode is connected in parallel with the relay to absorb this self-inductive voltage.1) The influence of the time parameter of the circuit below the ms level on the mechanical contact is ignored.2) Even the 1N4000 reverse recovery time is far below the ms level, and the forward conduction time is shorter.3) Capacitance between the driving tubes and parasitic capacitance of the relay is enough to disable the high-speed diode.4) The consumption of inductive energy storage mainly depends on the winding resistance, which is generally in an overdamped state.It is general to use transistors as switches. As shown in Figure, a transistor TR1 is used to control the conduction of the relay coil, and the relay contact is used to control the load circuit.In a thyristor circuit, the thyristor is generally used as a contact switch, if a large inductive load is controlled, a high-voltage back electromotive force will be generated, and the principle is the same as that of a relay.Flyback diode also used on displays coils commonly used in relays. It is often used with energy storage elements to prevent sudden changes in voltage and current and provide a path. The inductor can provide continuous current to the load to avoid sudden changes in load current and smooth the current. In the switching power supply, it is common to see a freewheeling circuit composed of a diode and a resistor connected in series. The following circuit is connected in parallel with the primary side of the transformer. Figure 4. Flyback Diode in Relay CircuitThe freewheeling diode is added to both ends of the inductive load, and the inductive here is to have an inductive characteristic. The characteristic of the inductive load is that the current cannot be abruptly changed, in other words, it can't be all of a sudden. Common inductive loads include relay coils and solenoid valves.Figure 5.  Typical Freewheeling CircuitThe Figure 5 shows the typical application circuit of the flyback diode, where the resistor R determined whether it is needed or not. When the energy storage element VT is turned on, the upper voltage is positive, and the lower voltage is negative, and the current direction is from top to bottom. When the VT is turned off, the current in the energy storage element is suddenly interrupted, and an induced potential is generated at this time. This induced potential and the power supply voltage are superimposed and applied to both ends of the VT, which can easily cause VT to break down. VD can be added for this purpose, so that the induced potential generated by the energy storage element can be short-circuited to achieve the purpose of protecting the VT. Ⅳ Selection1) Based on working voltage2) Based on working current1N4007 is a not bad choice but not the best, because the PLC may be damaged before the diodes have time to play the freewheeling effect. Therefore, it is best to use FR107 to protect the freewheeling circuit, which can better protect the PLC output interface, and the cost will not rise too much. It is also possible to choose IN5819 or IN5817, which has better performance than FR107, but the cost is a little higher. Ⅴ Applications5.1 SummaryFlyback diodes are usually used with energy storage elements, and their role is to prevent sudden changes in voltage and current in the circuit and provide a power-consuming path for reverse electromotive force. The inductive coil can provide continuous current to the load through EMF, so as not to change the load current and smooth the current. In the switching power supply, a freewheeling circuit always composed of a diode and a resistor connected in series. This circuit is connected in parallel with the primary side of the transformer. When the switch is turned off, the freewheeling circuit can release the energy stored in the transformer coil to prevent the induced voltage from being too large and breakdown the switch.5.2 In Forward Switching Power SupplyIn the forward switching power supply, when the MOS is turned off, the secondary side of the transformer provides current to the outside by the energy stored in the inductor. In order to make the inductor play this role under load, a freewheeling diode is added on the secondary side of the transformer. The inductor, load, and freewheeling diodes create paths to transfer the energy in the inductor to the outside.5.3 In Converter TechnologyIn the electronic converter circuit, the single-phase bridge rectifier in the rectification section is the single-phase rectifier circuit with the most practical applications. And three-phase bridge rectification is the most widely used method for power systems, especially generator excitation systems. Both of these circuits must be connected to a flyback diode. Its function is almost the same. Take a single-phase bridge circuit as an example: When the rectifier bridge is connected to an inductive load, because the inductor current cannot be abruptly changed, during the thyristor off time, it must connect freewheeling diode at both ends of the load to provide a smoothing path  to prevent dangerous overvoltages across the inductive load, and also the thyristor can be commutated to conduct.The three-phase bridge rectifier circuits used in generator excitation systems are divided into three-phase half-control bridges and three-phase full-control bridge circuits. Therefore, in order to ensure reliable commutation of the rectifier components, the half-control bridge needs to connect flyback diodes in parallel at both ends of the inductive load, while the full-control bridge does not need to do so. In addition, when the conduction angle is changed, the average voltage and line current of the half-controlled bridge change more slowly than the full-controlled bridge.At present, current converters such as rectifiers and inverters are now used in a large number of devices, in which flyback diodes are typically added to the internal DC bus of the converter. Because if the load is an inductive element, when a large-capacity inverter on the bus fails, the DC bus will generate huge reverse surge energy. At this time, it is necessary to provide a discharge channel for this energy, otherwise it will break down or burn the converter. This channel needs a diode to form, that is a flyback diode.5.4 In Unidirectional Half Wave Silicon Control Rectifier CircuitFor unidirectional half-wave silicon control rectifier circuit with large inductive load, when the  silicon control is turned off in the negative half cycle, the inductive load will generate a high reverse induced electromotive force. This reverse electromotive force is sufficient to cause the silicon control to break down and burn. After that, the reverse electromotive force can be discharged into the forward voltage drop of the diode (about 0.7V), thereby effectively protecting the circuit components. 5.5 In BUCK Circuit Figure 6. BUCK CircuitIn the BUCK circuit, fast recovery diodes or Schottky diodes are generally selected as freewheeling diodes. It is generally used in the circuit to protect components from being broken down or burned by induced voltage. The two ends of the element form a loop with it, so that the high electromotive force generated in the loop is consumed in a continuous current manner, thereby protecting the elements in the circuit.In theory, the diode is selected at least 2 times the maximum current. In actual use, due to the strong transient overload resistance of the diode, an ultra-fast diode with a maximum current of 50A can also be used. In addition, a reasonable heat sink generally has little damage in actual use. The total impedance when conducting is the internal resistance of the motor plus the equivalent internal resistance of the drive tube. And the total impedance during freewheeling is the internal resistance of the motor plus the equivalent internal resistance of the freewheeling diode. In general, the AC equivalent internal resistance of the freewheeling diode is smaller than the AC equivalent internal resistance of the driving transistor. Therefore, in conventional design, the maximum current of the freewheeling diode is generally doubled to the maximum current of the motor.The transient current is only a moment, and the anti-overload capability of the surface-contact diode is enough, as long as it is not used in overvoltage, if necessary, a small resistor can be connected in series to limit the current. The flyback diode is to protect the switching device. The transient current during freewheeling is related to the working voltage of the motor and the internal resistance of the winding, and has nothing to do with the power of the motor. If necessary, the peak value of the transient current is the reverse self-inductance voltage minus diode junction voltage drop and then divided by the loop resistance. The reason why a diode with a certain current used is because the internal resistance of the winding of the low-voltage high-power motor is low, so the transient current will be relatively large. A series of small resistors can suppress the peak current, the transient voltage of the switch tube rises slightly because the operating voltage is not high, and now the current withstand voltage of transistors is at least 50V or more. Ⅵ Something Has to CareFreewheeling diodes are commonly used in switching power supplies, relay circuits, thyristor circuits, IGBTs, and other circuits. They are widely used, so it is necessary to pay attention to the following points when using them: 1) Fylback diode is an effective method to prevent the high voltage generated by self-inductive potential from causing damage to related components when the DC coil is powered off.2) The polarity of the flyback diode must not be connected wrongly, otherwise a short circuit situation will be caused.3) The flyback diode is always reversed to the DC voltage, that is, the negative pole of the diode is connected to the positive pole of the DC power supply.4) The flyback diode works in the forward conduction state, not in the breakdown state or the high-speed switching state, that is, the flyback diode does not used in electrical breakdown, recoverable situation, but its unidirectional conduction effect is the key point.5) Zener diodes can't be regarded as flyback diode. Because the zener diodes use reverse characteristics, and the flyback diodes use forward characteristics. Frequently Asked Questions about Flyback Diode or Freewheeling Diode1. What is a flyback diode?A flyback diode is a diode connected across an inductor used to eliminate flyback, which is the sudden voltage spike seen across an inductive load when its supply current is suddenly reduced or interrupted. 2. What is the role of freewheeling diode?A Flyback diode is also called as freewheeling diode. ... Here catch diode is used to eliminate flyback, when the abrupt voltage spike is witnessed across the inductive load when the supply current abruptly reduced. It helps the circuit from damaging. 3. What is a flyback diode used for?A flyback diode is a diode connected across an inductor used to eliminate flyback, which is the sudden voltage spike seen across an inductive load when its supply current is suddenly reduced or interrupted. 4. How does a flyback diode work?The Flyback diode makes inductor to draw current from itself in a loop until the energy is dissipated in diode and wires. When the current flow to an AC induction motor is suddenly interrupted, then the inductor tries to maintain increasing the voltage and the current by reversing polarity. 5. How do you choose a freewheeling diode?The diode reverse voltage rating should be at least the voltage applied to the relay coil. Normally a designer puts in plenty of reserve in the reverse rating. A diode in your application having 50 volts would be more than adequate. Again 1N4001 will do the job. 6. How do I choose a flyback diode for a relay?Specify a diode for at least 79.4 mA current. In your case, a 1N4001 current rating far exceeds the requirement. The diode reverse voltage rating should be at least the voltage applied to the relay coil. Normally a designer puts in plenty of reserve in the reverse rating. 7. What are the advantages of freewheeling diode?What are the advantage of free wheeling diode in a Full Wave rectifier? It reduces the harmonics and it also reduces sparking and arching across the mechanical switch so that it reduces the voltage spike seen in a inductive load. 8. Why freewheeling diode is used in controlled rectifier?When the inductive circuit is switched off, this diode gives a short circuit path for the flow of inductor decay current and hence dissipation of stored energy in the inductor. This diode is also called Flywheel or Fly-back diode. circuits, inverter circuits, and chopper circuits by making it continuous. 9. What is the effect of adding free wheeling diode?It reduces the harmonics and it also reduces sparking and arching across the mechanical switch so that it reduces the voltage spike seen in a inductive load. 10. What is the use of freewheeling diode in converter circuit?A free wheeling diode is used in converter circuits . It is connected across the load. During positive cycle of input it is reverse biased. During negative cycle of input the diode conducts and the energy stored in the circuit inductor during the previous half cycle is delivered to the load itself.

Ⅰ IntroductionIn electronics, the transient interference of voltage and current source is the main cause of damage to circuits and equipment, and it often causes immeasurable losses to the society. These disturbances usually come from the  the starting and stopping operation of power equipment, instability of the AC grid, lightning interference and electrostatic discharge, etc. They are almost ubiquitous and always present. Therefore, scientists have developed a high-efficiency circuit protection device TVS to effectively suppress transient interference.TVS (transient voltage suppressor) is a new product developed on the basis of Zener diode technology. Its circuit symbol is the same as that of ordinary Zener diode. As a common circuit protection component, it is widely used in various fields: automotive electronics, consumer electronics, power drives, industrial power distribution, renewable energy, telecommunications, home appliances, measuring instruments, medical electronics, industrial control, lighting, security systems, building control and automation, audio / video equipment, computers, etc. Learn more about tvs diode, let's check the following transient voltage suppressor tutorial. TVS Diode Tutorial: Transient Voltage SuppressorCatalogⅠ IntroductionⅡ Terminology2.1 Basic Characteristics2.2 Electrical Characteristics2.3 Main ParametersⅢ TVS SelectionⅣ TVS vs Varistor, CapacitorⅤ Application Examples5.1 Lighting Protection5.2 Transistor Protection5.3 Electric Relay Protection5.4 Silicon Control Protection5.5 Integrated Op Amp Protection5.6 Integrated Circuit (IC) Protection5.7 Microcomputer System Protection5.8 DC Regulated Power Supply Protection5.9 Suppression of Electromagnetic Pulse Interference Ⅱ Terminology2.1 Basic CharacteristicsTVS diode, under the specified reverse application conditions, when subjected to a high-energy transient overvoltage pulse, due to it has a very fast response time (sub-nanosecond) and a very high  surge absorption ability, its working impedance can be immediately reduced to a very low on value, allowing large currents to pass, and clamping the voltage to a predetermined level, thereby effectively protecting precision components in electronic circuits from damage. TVS can withstand instantaneous pulse power up to kilowatts, and its clamp response time is only 1ps (10-12S). The forward surge current allowed by TVS can reach 50 ~ 200A under the conditions of TA = 250C and T = 10ms.TVS diodes work similarly to common Zener diodes. If the breakdown voltage is higher than the mark, the TVS diode will conduct. Compared with the Zener diode, the TVS diode has a higher current conduction capability. When the two poles of a TVS diode are subjected to reverse transient high-energy shocks, the high impedance between the two poles of the TVS diode becomes low at a speed of the order of 10 ^ -12S, while absorbing surge power of up to several kilowatts. The clamped voltage between the two poles is at a safe value, which effectively protects precision components in electronic circuits from being damaged by surge pulses. Figure 1. Working Characteristic Curve of TVS DiodeWhen the reverse voltage of the two poles of the TVS is greater than the maximum reverse voltage, it starts to conduct reversely; after the reverse voltage is greater than the breakdown voltage, it begins to be broken down, while the current starts to change suddenly; when the reverse voltage is greater than the maximum clamping voltage, the tube is in an avalanche breakdown state. At this time, the current flowing through the tube increases sharply, and the voltage difference across the tube does not change much (the voltage is clamped).Under specified reverse application conditions, the TVS diode will provide a low-impedance path, and the instantaneous current flowing to the protected component will be shunted to the TVS diode through a large current method, while the voltage across the protected component will be limited to the clamping voltage of TVS. When the overvoltage condition disappears, the TVS diode returns to a high impedance state.  Note: Unidirectional and Bidirectional TVS DiodesUnidirectional TVS SymbolBidirectional TVS Symbol1) Look at the signs: for unidirectional tvs diode, there is a thin color ring, connected to the positive electrode, and for bidirectional tvs diode, there are two rings in the middle, or there is no sign, no polarity.2) Look at the specifications: bidirectional tvs is bidirectional conduction, and unidirectional tvs is unidirectional conduction.3) Look at the model: The model name of the tvs tube is regular, and most of the tvs diode models can see the parameters on the case. For details, it is necessary to consult the manufacturer.4) Using multimeter tool: the unidirectional has voltage, while avalanche breakdown characteristics are available on the DC side; voltage is on both sides, and the DC side is symmetrical on both sides.Bidirectional tvs diodes can absorb instantaneous large pulse power in both forward and reverse directions and clamp the voltage to a predetermined level. In addition, bidirectional TVS is suitable for AC circuits, and unidirectional TVS is generally used for DC circuits. 2.2 Electrical Characteristicsa. Unidirectional TVS (V-I characteristic) Figure 2. Unidirectional TVS DiodeThe unidirectional tvs diode has the same forward characteristics as ordinary Zener diodes, and the reverse breakdown inflection point is approximately “right angle” as a hard breakdown and is a typical PN junction avalanche device. The curve segment from the breakdown point to the VC value indicates that when there is a transient overvoltage pulse, the current of the device increases sharply while the reverse voltage rises to the clamped voltage value and remains at this level.b. Bidirectional TVS (V-I characteristic) Figure 3. Bidirectional TVS DiodeThe V-I characteristic curve of the bidirectional tvs diode is similar to the two back-to-back unidirectional tvs diodes combination. Its forward and reverse directions have the same avalanche breakdown characteristics and clamping characteristics. The symmetry relation of the breakdown voltage on both sides of the positive and negative is as follows: 0.9≤ VBR(positive)/(inverse) ≤1.1, once the interference voltage at both ends of it exceeds the clamping voltage will be immediately suppressed, thus the bidirectional tvs are very convenient for ac loop application.  2.3 Main Parameters1) breakdown voltage V(BR)In the region where the device breaks down, the voltage across the device is measured at the specified test current I (BR), which is called the breakdown voltage. In this area, the tvs diode becomes a low impedance path.2) maximum reverse pulse peak current IPPIn reverse operation, IPP refers to the maximum pulse peak current allowed by the device under specified pulse conditions. The product of IPP and the maximum clamping voltage VC (max) is the maximum value of the transient pulse power.The TVS should be properly selected during use, so that the rated transient pulse power PPR is greater than the maximum transient surge power that may occur in the protected device or wires.When the instantaneous pulse peak current appears, the TVS is broken down and its breakdown voltage value rises to the maximum clamping voltage value. As the pulse current decreases exponentially, the clamping voltage also decreases and returns to the original state. Therefore, TVS diode can suppress the impact of possible pulse power to effectively protect the electronic circuits.The test waveform of the TVS peak current uses a standard wave (exponential waveform), which is determined by TR / TP.Peak current rise time TR: The time from when the current reaches 0.9 IPP from 0.1 IPP.Half-peak current time TP: The time after the current passes through the maximum peak from zero and then drops to 0.5 IPP.The TR / TP values of typical test waveforms are listed below:A. EMP wave: 10ns / 1000nsB. Lightning wave: 8μs / 20μsC. Standard wave: 10μs / 1000μs3) Maximum reverse working voltage VRWMWhen the device operates in reverse, the voltage across the device is called the maximum reverse operating voltage VRWM under the specified IR, usually VRWM = (0.8 ~ 0.9) V(BR). At this voltage, the power consumption of the device is small. When used, VRWM should not be lower than the normal working voltage of the protected device or circuits.4) Maximum clamping current VC(max)The maximum voltage value across the device under the peak pulse current IPP is called the maximum clamping voltage. When used, VC (max) should not be higher than the maximum allowable safe voltage of the protected device. And the ratio of the maximum clamping voltage to the breakdown voltage is called the clamping coefficient.Clamping coefficient = VC(max) / V(BR), the general clamping coefficient is about 1.3.5) Reverse pulse peak power PPRThe PPR of TVS depends on the pulse peak current IPP and the maximum clamping voltage VC (max). In addition, it is also related to the pulse waveform, pulse time and ambient temperature.When the pulse time Tp is constant, PPR = K1‧K2‧VC (max) ‧IPP(K1 is the power coefficient, and K2 is the temperature coefficient of the power) The typical pulse duration tp is 1MS. When the pulse time tp applied to the transient voltage suppression diode is shorter than the standard pulse time, its peak pulse power will increase as tp is shortened.Figure 4. Peak Pluse Power vs Pluse TimeTVS reverse pulse peak power PPR is related to the pulse waveform subjected to surge, expressed by the power coefficient K1: E=∫i(t)‧V(t)dt     i (t) is the pulse current waveform, and V (t) is the clamping voltage waveform.This rated energy value is not reproducible to TVS in a very short time. However, in practical applications, surges often occur repeatedly. In this case, even if the single pulse energy is much smaller than the pulse energy that the TVS device can withstand, if repeat, these single pulse energy will accumulated, in some cases, it will exceed the pulse energy that the TVS device can withstand. Therefore, the circuit design must carefully consider and select the TVS device, so that the accumulation of pulse energy repeatedly applied within the specified interval does not exceed the pulse energy rating of the TVS device.6) Capacitance CPP  Figure 6. The Capacitance of TVS CircuitThe capacitance of TVS is determined by the area of the silicon sheet and the bias voltage. In the case of zero bias, the capacitance value decreases with the increase of the bias voltage. The value of the capacitance will affect the response time of the TVS device.7) Leakage current IRWhen the maximum reverse working voltage is applied to the TVS, the TVS tube has a leakage current IR. When the TVS is used in a high impedance circuit, the leakage current is an important parameter. In practice, especially in automotive electronics, this parameter affects static current.  Ⅲ TVS SelectionWhen selecting tvs diode, the specific conditions of the circuit must be considered, and generally the following principles should be followed:1) The clamping voltage VC (max) is not greater than the maximum allowable safe voltage of the circuit.2) The maximum reverse working voltage VRWM is not lower than the maximum working voltage of the circuit. Generally, VRWM can be selected to be equal to or slightly higher than the maximum working voltage of the circuit.3) The rated maximum pulse power must be greater than the maximum transient surge power present in the circuit. Ⅳ TVS vs Varistor, Capacitor1) TVS diode and varistor do not have switching characteristics like switching elements, but have voltage regulation characteristics like zener diodes.2) The varistor can withstand a larger surge current, and the larger the varistor can withstand the larger surge current, which can reach tens of kA to hundreds of kA at the maximum; but the non-linear characteristics of the varistor are poor and the limiting voltage is higher at large current, and the leakage current is larger at low voltage.3) The non-linear characteristics of TVS diodes are the same as those of Zener tubes. Leakage current before breakdown is very small. After the breakdown, it is in a standard voltage stabilization. Compared with varistors, the maximum clamping voltage of TVS diode is smaller, but its current capability is poor than a varistor. Since the breakdown voltage VBR and the clamping voltage VC of the varistors are relatively high, the current flow capability is relatively strong, and the surge pulse absorption capability is stronger, so it is more suitable for ESD or surge protection of the power interface.4) For the reaction speed, the response speed of the TVS is fast (ps level), while the varistor’s is slow ( ns level). In addition, the capacitance of both is large (ps: TVS also have low capacitance products).5) The TVS tube has high reliability, and a long service life, while the varistor has poor reliability, easy aging and short service life.Other ViewCompared with ceramic capacitors, TVS diodes can withstand a voltage of 15 kV, but ceramic capacitors have a lower ability to withstand high voltages. A 5 kV shock will cause about 10% of the ceramic capacitor to fail, and by 10 kV, its damage rate will reach 60%. Ⅴ Application Examples5.1 Lighting ProtectionIn thunderstorm-prone areas, lightning-induced voltage often breaks down some of the integrated circuits in a computer network. The reason is that cables are damaged due to transient high voltage caused by lightning induction, by installing tvs diodes in the microcomputer, it is useful to reduce damages and commercial loss. And the result shows that it is very practical, and it can improve the reliability of the whole machine application.TVS also have many other applications, for example, for VMOS high power transistors, the tvs diodes between the gate and the source and the machine can prevent gate breakdown and improve the reliability of the VMOS power tube application. 5.2 Transistor ProtectionVarious transient voltages can cause damage to the EB junction or CE junction of the transistor. Especially when the collector of the transistor has an inductive load (coil, transformer, motor), a high-voltage back-EMF can be generated, which often causes the transistor to be damaged. It is necessary to use a tvs diode as a protector. 5.3 Electric Relay ProtectionRelay contacts often use large currents to switch on and off high-current inductive loads such as motors, and the inductor has a high back electromotive force when switching, and has a large amount of energy. What’s more, the contacts are burned or broken to produce an arc, and the surge current generated by the arc is very large. To protect the contacts by suppressing the occurrence of arcs to protect the relays, adding a tvs diode is more effective. In the past, a capacitor or a capacitor series resistor, a diode or a diode series resistor and other suppression methods were used. 5.4 Silicon Control ProtectionThe thyristor may has wrong trigger and cause malfunction. The control electrode current cannot be too large and the voltage cannot be too high, in order to do it, TVS can be used for protection. 5.5 Integrated Op Amp ProtectionIntegrated op amps are very sensitive to external electrical stress. In the process of using op amps, if having excessive voltage or current due to operating errors or abnormal working conditions, especially surges and electrostatic pulses, it is easy to damage the op amp. In the integrating circuit, if the capacitor is charged and discharged to a high potential, and then the power supply voltage is cut off, a transient voltage will be generated at the input terminal, and a large discharge current will occur, resulting in damage to the operational amplifier. At this time, tvs protection method adopted at the input terminal of op amp to avoid device damage. If the capacitance value is large (such as greater than 0.1μF), the protecting effect will be very significant. 5.6 Integrated Circuit (IC) ProtectionAs integrated circuits become more integrated, their withstand voltages are getting lower and lower, and they are easily damaged by transient voltages. Protective measures must be taken, for example, adding tvs diode in the circuit, the CMOS circuit has a protection network at its input and output ends. 5.7 Microcomputer System ProtectionIn a typical microcomputer system, various interference or transient voltages entering through the power line, input line, and output line may cause the microcomputer to malfunction and fail, especially from the switching power supply. The on-off motor near the microcomputer, voltage surges and transients of AC power, electrostatic discharges, etc. may cause the system to fail, and in severe cases may damage the device. Connecting the tvs diode to the input and output lines of the power supply of the microcomputer can prevent the transient voltage from entering the “microcomputer” bus, strengthen the microcomputer's resistance to external interference, ensure the normal operation, and improve its reliability. 5.8 DC Regulated Power Supply ProtectionA DC regulated power supply with a transistor that expands the current output, adding a tvs diode to its regulated output can protect the equipment, and can also absorb peak voltage from the collector to the emitter in the circuit to protect the transistor. In a word, adding a tvs diode at the output end of each voltage stabilization source can greatly improve the reliability of the whole operation. 5.9 Suppression of Electromagnetic Pulse InterferenceA nuclear explosion will cause a strong electromagnetic pulse, which causes induced voltage in the wire. If the induced voltage exceeds the breakdown voltage of the device, it may cause the breakdown of the component, especially for long-term transmission, it is more easily to cause high voltage.TVS diodes are connected in parallel to the signal and power lines, which can absorb the induced voltage caused by electromagnetic pulses, ensure the reliability of the system, and avoid radiation damage to components. Frequently Asked Questions about Transient Voltage Suppression Diode1. How does a transient voltage suppressor work?Transient Voltage Suppressor Diode is a clamping device, so whenever the induced voltage exceeds the avalanche breakdown voltage, it absorbs the excess energy of the overvoltage event, and then it automatically resets after overvoltage condition. 2. What does a transient suppressor do?A transient voltage suppressor or TVS is a general classification of an array of devices that are designed to react to sudden or momentary overvoltage conditions. ... This makes TVS devices or components useful for protection against very fast and often damaging voltage spikes. 3. What is a transient voltage surge suppressor?A transient voltage surge suppressor is a device which is installed on an AC or DC power line to act as a cutoff if there is a momentary surge of electrical power, also known as a “transient.” TVSS devices are considered crucial to the protection of sensitive equipment which would result in circuitry damage or data. 4. What is a voltage transient?A transient voltage is a temporary unwanted voltage in an electrical circuit that range from a few volts to several thousand volts and last micro seconds up to a few milliseconds. ... Faulty contactors and lightning are the most common source of transients. 5. How does a transient voltage suppressor diode work?Transient Voltage Suppressor Diode is a clamping device, so whenever the induced voltage exceeds the avalanche breakdown voltage, it absorbs the excess energy of the overvoltage event, and then it automatically resets after overvoltage condition. 6. Which device can be used as a transient suppressor?Transient voltage suppression diodeOne such common device used for this purpose is known as the transient voltage suppression diode that is simply a Zener diode designed to protect electronics device against overvoltages. 7. What does a suppression diode do?A transient-voltage-suppression (TVS) diode, also transil or thyrector, is an electronic component used to protect electronics from voltage spikes induced on connected wires. 8. What is the difference between Zener and TVS diode?Zener diodes are used to make the voltage more stable. They act as a regulator as well as a protective device. TVS diode is intended to prevent high voltage transients such as Surge and ESD damaging. 9. Where are transient voltage most dangerous?Transient voltages are most dangerous while taking measurements on equipment. Should someone turn something off it could cause a transient voltage spike. 10. What is transient protection?Transients (momentary spikes in voltage or current) can disrupt or damage the products connected to signal or power lines. The most common transient protection schemes limit the voltage amplitude, current amplitude or transition times on the circuit they are protecting.