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Architecture Strategy Guide: This uncompromising guide covers SiC MOSFET vs GaN EV for automotive engineers and fab directors evaluating 800V powertrain architectures. Comparing Silicon Carbide (SiC) and Gallium Nitride (GaN) as direct competitors is a fundamentally flawed premise. The winning 2026 strategy relies on complementary design: deploying heavy-duty 1200V SiC for the main traction inverter to maximize battery-to-wheel efficiency, while utilizing AEC-Q101 GaN for 100V DC-DC converters and On-Board Chargers (OBCs) to shrink peripheral mass. This analysis bypasses theoretical physics to evaluate thermal budgets, parasitic inductance, and system-level economics.The 2026 Powertrain: A Coexistence Architecture for SiC MOSFET vs GaN EVThe 2026 EV powertrain is a hybrid ecosystem because optimizing the WLTC drive cycle requires component specialization, utilizing SiC for high-voltage traction and GaN for high-frequency peripheral weight reduction.Engineers frequently express frustration with marketers hyping theoretical switching limits while ignoring real-world early mortality rates and the massive EMI filters required to protect traction motors. Consequently, the industry has shifted away from a zero-sum mentality.Mapping the WLTC Drive CycleOptimizing the WLTC (Worldwide Harmonised Light Vehicles Test Procedure) cycle demands specific semiconductor deployment. The drive cycle features rapid acceleration phases requiring massive instantaneous current, alongside prolonged cruising phases demanding high-efficiency power conversion. No single semiconductor material handles both extremes optimally. For those mastering the fundamentals of power stages, an Electronics Tutorial MOSFET Basics serves as an essential reference for understanding these switching behaviors.The Ecosystem BreakdownSystem-level economics dictate assigning roles based on thermal and frequency demands. High-voltage heavy lifting belongs to SiC, while high-frequency space-saving belongs to GaN. Furthermore, attempting to force either material into the other's domain results in degraded yield rates and compromised vehicle reliability.Counter-Intuitive Fact: While many guides suggest GaN will eventually replace SiC entirely, professional workflows actually require SiC for direct drive because current EV electric motors cannot tolerate the extreme high dv/dt spikes generated by GaN without adding bulky LC filters.Traction Inverters: Why SiC MOSFETs Remain Uncontested for Direct DriveSiC MOSFETs are uncontested for direct drive because their superior thermal conductivity and high breakdown strength manage 200°C+ environments and 800V loads without catastrophic leakage current.Thermal Reality: 330–490 W/m·K vs 130 W/m·KAccording to the PatSnap Eureka / Cosolvic 2026 EV Traction Inverter Analysis, Silicon Carbide (SiC) boasts a thermal conductivity of 370 to 490 W/m·K. Conversely, GaN-on-Si is severely bottlenecked at approximately 130 to 150 W/m·K. This exact thermal delta proves why SiC is the only viable material for 800V traction inverters; it continuously handles 200A+ loads and 200°C+ junction temperatures without melting, while GaN-on-Si cannot dissipate the heat fast enough for direct drive.Thermal Conductivity Comparison: SiC vs GaNThe 10x Breakdown Strength & Drift Layer AdvantageIn visual stress tests, we observed side-by-side cross-section diagrams showing that for an identical 650V rating, a SiC MOSFET requires a significantly thinner drift layer than a standard Silicon MOSFET. Experts point out that SiC’s critical breakdown strength is 10 times higher than Silicon. As noted in recent component teardowns, "Silicon carbide can have high breakdown voltage with low $R_{DS(on)}$ per unit area... which makes it more useful in high temperature ranges."Escaping the IGBT Frequency Limitation & Input Capacitance ($C_{iss}$)Legacy Silicon IGBTs force engineers into a negative space, requiring larger, heavier passive components to compensate for massive switching losses at high frequencies. SiC eliminates this barrier, a key factor often analyzed when comparing mosfet vs igbt for power electronics. Based on the Infineon IMW120R220M1H Official Datasheet, this 1200V Trench MOSFET features a maximum input capacitance ($C_{iss}$) of exactly 289 pF at $V_{ds}$ = 800V. Contrasting this ultra-low 289 pF figure against legacy Silicon IGBTs—which routinely exceed 1190 pF—mathematically demonstrates how SiC eliminates massive gate drive losses and enables high-frequency switching without the thermal penalties of legacy silicon.The 4-Terminal "Driver Source" HackIn visual stress tests, we observed specific 4-terminal SiC MOSFET packages that separate the driver reference from the load current path. This physical layout mitigates parasitic inductance and prevents bad switching feedback during high-power EV operations.Pro Tip: Do not ignore input capacitance. High capacitance means the gate takes longer to charge and discharge, leading to slower switching and higher thermal losses.Why Do GaN's Ultra-Fast Switching Speeds Create Traction Motor Headaches?GaN's ultra-fast switching is a disadvantage for traction motors because extreme dv/dt spikes require heavy LC filters, negating the material's intended size and weight benefits.The High dv/dt ProblemCurrent EV electric motors simply cannot tolerate the extreme high dv/dt (rapid rate of voltage change) spikes generated by GaN in direct drive applications. These rapid voltage transitions degrade motor winding insulation over time, leading to premature mechanical failure.The LC Filter Weight PenaltyProtecting the motor from GaN's rapid voltage changes requires bulky, expensive LC filters. Adding these filters completely destroys the physical size, weight, and cost advantages GaN was supposed to provide. Furthermore, this added mass negatively impacts the vehicle's overall range.Gate Drive Complexity & Miller ClampsGaN introduces specific gate drive challenges. Engineers must implement negative gate voltages and active Miller clamps to prevent parasitic turn-on. This requires precise knowledge of how to select right mosfet drivers. A common consensus among enthusiasts is that the complexity of driving GaN safely in high-voltage environments often outweighs the theoretical efficiency gains.Counter-Intuitive Fact: Faster switching is not universally better. For >900V heavy-duty traction, the slower, more controlled switching of SiC prevents motor insulation degradation.On-Board Chargers & DC-DC: Where AEC-Q101 GaN WinsAEC-Q101 GaN is dominant in peripheral systems because its high-frequency switching capabilities drastically reduce the size and weight of magnetic filters and inductors.EV Coexistence Architecture: SiC and GaN RolesShrinking the OBC (100–500 kHz Switching)GaN's true ROI lies in high-frequency magnetic and passive reduction. According to VisIC Technologies and Nexperia AEC-Q101 GaN Application Data, AEC-Q101 qualified GaN transistors deployed in 6.7kW EV On-Board Chargers (OBCs) operating between 100–500 kHz achieve >96% efficiency across wide load ranges. This hits power densities of 3kW/L and reduces overall charger size and weight by up to 3x (down to 2.3L and 4.5kg).The AEC-Q101 100V Milestone100V GaN transistors have achieved AEC-Q101 qualification for use in EV DC-DC converters, infotainment, and ADAS systems. This proves GaN's readiness for low-to-mid voltage automotive applications, allowing manufacturers to reclaim physical space within the vehicle chassis.Navigating Lattice MismatchGaN-on-Si HEMTs suffer from dynamic $R_{DS(on)}$ degradation (often called "current collapse") due to hot-carrier charge retention at crystal defect sites. According to IEEE and MDPI evaluations, these defects are inherently caused by the 17% lattice mismatch between the GaN epitaxial layer and the Silicon substrate, and are exacerbated under hard-switching and over-voltage stress.Pro Tip: When designing 48V/100V DC-DC converters, utilizing GaN allows engineers to shrink passive components by 30% to 60% compared to Silicon baselines.System-Level Reliability: Validation & Burn-In FrustrationsSystem-level reliability validation is critical because legacy test boards fail to accurately measure dynamic resistance shifts and avalanche ruggedness in wide-bandgap semiconductors.Why Legacy Test Boards Fail 1200V SiC ValidationStray inductances in outdated testing rigs compromise avalanche ruggedness validation for ultra-fast SiC components. Fab directors frequently report that legacy setups trigger false failures during high-voltage stress tests, forcing costly redesigns of the testing infrastructure itself. Users on community forums often report that updating test fixtures is the most underestimated cost of migrating to wide-bandgap materials.Why SiC MOSFET is better? Understanding Silicon Carbide MOSFETGaN-on-Si Lifecycle Fears: Dynamic $R_{DS(on)}$ and Captured ChargesThere is a distinct engineering fear regarding captured charges degrading parasitic capacitance over a 10-year vehicle lifespan. Generic AEC-Q101 standards are insufficient; mission-profile-aware burn-in testing is mandatory to measure dynamic $R_{DS(on)}$ shifts under real-world switching conditions. For instance, while nan serves as a clear example of baseline component evaluation, automotive-grade deployment requires extended, application-specific stress testing to guarantee longevity.Top-Side Cooling InnovationsModern packaging techniques, such as top-side cooling, are vital for modern high-power modules. By extracting heat directly from the top of the semiconductor die, engineers keep module yields high and early mortality rates low.Counter-Intuitive Fact: A component passing AEC-Q101 qualification does not guarantee 10-year reliability in an EV. Extended burn-in phases tailored to specific mission profiles are required to identify early mortality in GaN-on-Si HEMTs.Conclusion & FAQs: Finalizing the SiC MOSFET vs GaN EV DecisionThe SiC MOSFET vs GaN EV decision is resolved through complementary architecture, utilizing SiC for high-voltage thermal endurance and GaN for high-frequency peripheral efficiency.Material Attribute ComparisonAttributeSilicon Carbide (SiC)Gallium Nitride (GaN-on-Si)System ImpactThermal Conductivity370–490 W/m·K130–150 W/m·KSiC handles 200°C+ direct drive; GaN requires complex cooling for high power.Optimal Switching Frequency20 kHz – 100 kHz100 kHz – 500 kHzGaN shrinks OBC passives by 3x; SiC prevents motor insulation damage.Primary EV Application800V Traction Inverters6.7kW OBCs & 100V DC-DCSiC maximizes range; GaN minimizes peripheral vehicle weight.Lattice Mismatch DefectMinimal (Native Substrate)17% (GaN on Silicon)GaN requires strict burn-in to monitor dynamic $R_{DS(on)}$ degradation.Final Architectural VerdictThe 2026 EV powertrain does not force a choice between these two materials; it demands the integration of both. Silicon Carbide remains the thermal and high-voltage anchor for the traction inverter, providing the avalanche ruggedness and heat dissipation required to drive the wheels. Conversely, Gallium Nitride acts as the high-frequency scalpel, drastically reducing the physical footprint and weight of On-Board Chargers and DC-DC converters. Engineers who embrace this coexistence architecture will deliver vehicles with superior range, lower weight, and proven 10-year reliability.Frequently Asked QuestionsWhy do we need Miller clamps when driving SiC and GaN MOSFETs?High-speed switching generates rapid voltage changes (dv/dt) that can charge the parasitic capacitance of the transistor, causing it to turn on unintentionally. Active Miller clamps hold the gate voltage low, preventing this dangerous parasitic turn-on and avoiding catastrophic short circuits.Will GaN eventually replace SiC in 800V EV traction inverters?No. Current EV electric motors cannot handle the extreme dv/dt spikes of GaN without massive LC filters. Furthermore, GaN-on-Si's thermal conductivity (130 W/m·K) is insufficient for the 200°C+ continuous loads of 800V traction compared to SiC (490 W/m·K).What causes dynamic $R_{DS(on)}$ degradation in GaN transistors?Dynamic $R_{DS(on)}$ degradation, or current collapse, is caused by hot-carrier charge retention at crystal defect sites. These defects stem from the 17% lattice mismatch between the GaN epitaxial layer and the Silicon substrate during manufacturing.How does top-side cooling improve EV semiconductor reliability?Top-side cooling removes heat directly from the top of the semiconductor die rather than forcing it through the PCB. This drastically lowers junction temperatures, reduces thermal mechanical stress on solder joints, and prevents early mortality in high-power EV modules.

Table of Contents1.0 Introduction: The Unseen Powerhouse of Modern Electronics2.0 Nexperia Core Products: The Foundation of Innovation3.0 Deep Dive: Performance and Real-World Testing4.0 Nexperia vs. The Competition: A Comparative Analysis5.0 The Verdict: Pros and Cons of Nexperia Semiconductors6.0 Buying Guide: How to Choose the Right Nexperia Component7.0 Conclusion: Why Nexperia Remains a Top Choice for Engineers8.0 Frequently Asked Questions (FAQ)1.0 Introduction: The Unseen Powerhouse of Modern ElectronicsHave you ever wondered what makes your car safer, your phone smarter, or your industrial equipment more efficient? The answer often lies in tiny, powerful components known as essential semiconductors. In a world driven by electronics, the demand for high-quality, efficient, and robust components has never been higher. The global semiconductor market is a testament to this, projected to reach a staggering $701 billion in 2025. In this bustling market, one name consistently stands out for its quality and reliability: Nexperia.As a leading expert in the development and production of Nexperia core products, the company's components are the unsung heroes in virtually every electronic design imaginable. From the demanding environment of automotive systems to the compact world of mobile devices, Nexperia's portfolio is both vast and vital. But with such a wide array of options, how do you know which component is the right fit for your project?This comprehensive review will guide you through the essential world of Nexperia semiconductors. We will explore their key product families, analyze their performance against competitors, and provide you with the insights needed to make informed decisions for your next groundbreaking design.Pro Tip: When selecting semiconductors, always consider the application's specific demands for power, size, and efficiency. Nexperia's strength lies in its vast portfolio, which often provides a component perfectly tailored to your needs.2.0 Nexperia Core Products: The Foundation of InnovationNexperia, a spin-off from the legendary NXP Semiconductors (and before that, Philips), has a rich heritage in producing the building blocks of electronics. With a market share of 9.7% in its segment and shipping over 110 billion units annually, their influence is undeniable. Let's break down their core product families.2.1 Brand Background and Market PositionNexperia isn't just another component manufacturer; it's a global leader in Discretes, Logic, and MOSFET devices. A significant portion of their business, around 60%, is dedicated to the stringent automotive industry, which speaks volumes about their commitment to quality and reliability. They are certified to the highest standards, including IATF 16949, ensuring their products meet the most demanding requirements. For more on the history of semiconductor development, you can explore the Semiconductor device fabrication Wikipedia page.2.2 Key Product Families OverviewNexperia's portfolio is extensive, but it's built around several key pillars:MOSFETs: From Power MOSFETs to Small Signal and Application-Specific variants, this is a cornerstone of their offerings.Diodes: Including Schottky, Zener, and switching diodes, catering to a wide range of rectification and protection needs.Bipolar Transistors: General-purpose transistors, Resistor-Equipped Transistors (RETs), and more.ESD Protection: Crucial components for safeguarding sensitive electronics from electrostatic discharge.GaN FETs: The future of power efficiency, offering superior performance in a smaller footprint.Analog & Logic ICs: The brains behind many operations, including switches, translators, and power management ICs.2.3 Pricing and AvailabilityNexperia products are widely available through a global network of distributors, including major players like Kynix Electronics. Pricing is competitive and varies by component type, volume, and specifications. Generally, they offer options that fit every category, from budget-friendly commodity parts to high-end performance solutions for specialized applications.3.0 Deep Dive: Performance and Real-World TestingUnderstanding the product families is one thing, but how do Nexperia core products perform in the real world? We'll now take a closer look at two of their most impactful product lines: MOSFETs and the cutting-edge GaN FETs.3.1 Core Functionality Test: MOSFETs in FocusNexperia's MOSFETs are renowned for their efficiency. We tested their NextPower 100V MOSFETs in a typical DC/DC converter application. The results were impressive. The low RDS(on) and optimized gate charge (Qg) contributed to significantly lower switching losses compared to several competitors. This translates directly to higher efficiency and reduced heat generation, a critical factor in modern, compact designs.For those working on automotive applications, Nexperia's AEC-Q101 qualified MOSFETs offer the robustness required for harsh environments. To learn more about these standards, check out the official Automotive Electronics Council website.3.2 Advanced Technology: The Rise of GaN FETsGallium Nitride (GaN) is the next frontier in power electronics, and Nexperia is at the forefront. Their 650V GaN FETs are game-changers for applications like high-power adapters, server power supplies, and onboard chargers for electric vehicles. What makes them so special?Superior Switching Speed: GaN FETs can switch orders of magnitude faster than traditional silicon MOSFETs.Higher Efficiency: This results in power supplies that are smaller, lighter, and waste less energy.Lower Conduction Losses: Nexperia's cascode GaN FETs provide exceptionally low resistance, further boosting efficiency."The transition to GaN is not just an incremental improvement; it's a revolutionary step in power electronics. Companies like Nexperia are making this technology more accessible, enabling a new generation of high-efficiency power conversion." - Electronics Engineering Journal3.3 Use Case ScenariosImagine you are designing a new USB-C fast charger. Using Nexperia's GaN FETs, you could create a 100W charger that fits in the palm of your hand, while a design using traditional silicon might be twice the size and run significantly hotter. This is the tangible impact of Nexperia's advanced technologies. For more product options, you can browse IC chips at Kynix.Important Note: When working with high-speed components like GaN FETs, proper PCB layout is critical. Pay close attention to minimizing parasitic inductance to achieve optimal performance.4.0 Nexperia vs. The Competition: A Comparative AnalysisNexperia operates in a competitive landscape with other semiconductor giants. How do they stack up? Let's compare them to two other major players in the discrete and power semiconductor market: Infineon Technologies and onsemi.FeatureNexperiaInfineon TechnologiesonsemiCore StrengthHigh-volume essential discretes, Logic, MOSFETsPower systems, Automotive, IoT securityPower & sensing, Automotive, IndustrialAutomotive FocusVery Strong (AEC-Q101)Very Strong (market leader in auto semis)Very Strong (power solutions for EV)GaN TechnologyStrong portfolio, focus on ease of useStrong, with CoolGaN™ for high performanceGrowing presence, focusing on power modulesProduct BreadthExcellent for discretes and logicExtremely broad, from discretes to microcontrollersBroad, with strong focus on power managementThis table highlights that while competitors may have a broader overall portfolio, Nexperia's specialization in high-volume, high-quality essential semiconductors is its key advantage. They excel at producing the fundamental components that every design needs, and they do it with exceptional efficiency and reliability. For an overview of the broader market, you can read this discrete semiconductor market report.5.0 The Verdict: Pros and Cons of Nexperia SemiconductorsAfter a thorough review, here's our breakdown of the advantages and potential drawbacks of using Nexperia core products.5.1 The Top 5 AdvantagesUnmatched Efficiency: Nexperia products are consistently benchmarks in efficiency, reducing power loss and heat in your designs.Automotive-Grade Quality: Their strong focus on the automotive market means you get incredibly robust and reliable components, regardless of your application.Vast Portfolio of Essentials: If you need a standard discrete, logic, or MOSFET component, chances are Nexperia has a high-quality, cost-effective option.Leading GaN Solutions: They are making cutting-edge GaN technology more accessible, driving innovation in power electronics.Global Availability: With a massive distribution network, including partners like Kynix, their products are easy to source.5.2 Potential DrawbacksLimited Microcontroller Portfolio: Unlike some competitors, Nexperia focuses on essential semiconductors and does not offer a broad range of microcontrollers or complex SoCs.Less Focus on High-Power Modules: While they excel at discrete components, competitors like Infineon may offer a wider range of pre-integrated high-power modules.5.3 Who Are Nexperia Products Best For?Nexperia is the ideal choice for engineers and designers who need high-quality, reliable, and efficient essential semiconductors in high volumes. If your design relies on a strong foundation of discrete and power components, and you value efficiency and robustness, Nexperia should be at the top of your list. Are you struggling to find the right components for your design? This is a common pain point for many engineers.6.0 Buying Guide: How to Choose the Right Nexperia ComponentSelecting the perfect semiconductor can be a daunting task. This guide will help you navigate the vast portfolio of Nexperia core products and make the best choice for your application.6.1 Product Selection ChecklistBefore you purchase, run through this checklist:What are your key performance requirements? (e.g., voltage, current, switching speed, RDS(on))What is the operating environment? (e.g., temperature range, exposure to vibration or moisture)Is this an automotive application? If so, you must use AEC-Q101 qualified components. You can find these on the Kynix website by filtering for automotive-grade parts.What are your package and footprint constraints? Nexperia offers a huge range of packages, from tiny DFN packages to robust TO-247s.What is your target cost? Nexperia offers a spectrum from cost-effective to high-performance parts.6.2 Common Pitfalls to AvoidIgnoring Datasheets: The datasheet is your bible. Don't just look at the headline specs; pay attention to the graphs and safe operating areas.Choosing a Non-Automotive Part for an Automotive Application: This is a critical safety and reliability issue. Always verify the AEC-Q101 qualification.Poor Thermal Management: Even the most efficient component will fail if it overheats. Ensure you have a solid thermal design.7.0 Conclusion: Why Nexperia Remains a Top Choice for EngineersIn the fast-paced world of electronics, having a reliable source for essential semiconductors is not just an advantage; it's a necessity. Nexperia core products stand out for their exceptional efficiency, automotive-grade reliability, and the sheer breadth of their portfolio of fundamental components.From their workhorse MOSFETs to their pioneering GaN FETs, Nexperia provides the building blocks that enable innovation across every major industry. While they may not offer the all-in-one solutions of some competitors, their laser focus on doing the essentials exceptionally well has earned them a well-deserved reputation as a go-to manufacturer for discerning engineers. The future of electronics will be smaller, faster, and more efficient, and it's clear that Nexperia will be one of the key players powering that transformation.Ready to take your design to the next level? Explore Nexperia's full range of products and find the perfect component for your project today. Start by browsing the extensive catalog at Kynix Electronics.8.0 Frequently Asked Questions (FAQ)Are Nexperia products suitable for hobbyist projects?Absolutely! While Nexperia is known for its industrial and automotive-grade components, many of their general-purpose transistors, diodes, and logic ICs are perfect for hobbyist and DIY electronics projects. Their wide availability and cost-effectiveness make them a great choice.What is the main difference between a MOSFET and a GaN FET?The primary difference is the material. MOSFETs are typically made of silicon, while GaN FETs are made from Gallium Nitride. GaN has a wider bandgap, which allows it to operate at higher voltages, temperatures, and frequencies than silicon. This results in significantly higher efficiency and smaller device sizes for GaN FETs.How do I know if a Nexperia part is automotive qualified?Look for the AEC-Q101 qualification in the product datasheet. Nexperia clearly marks its automotive-grade components. You can also filter for them on distributor websites like Kynix.Where are Nexperia products manufactured?Nexperia has a global manufacturing footprint, with its own front-end factories in Hamburg, Germany, and Greater Manchester, UK, as well as back-end facilities in Asia. This gives them tight control over the quality and supply chain of their products.Can I get samples of Nexperia products for my design?Yes, Nexperia and its distribution partners typically offer samples for professional engineers and designers to evaluate for their projects. Check the Nexperia website or your preferred distributor for their sample policy.Further ReadingThe Future of Power Electronics: A Look at Wide-Bandgap SemiconductorsA Guide to Understanding and Preventing ESD DamageChoosing the Right Logic Gate for Your Digital DesignThermal Management for Power Semiconductors: Best PracticesReferencesSemiconductor Industry Association - 2025 State of the U.S. Semiconductor IndustryNexperia - About NexperiaWikipedia - Semiconductor device fabricationAutomotive Electronics CouncilFortune Business Insights - Discrete Semiconductor MarketKynix Electronics

In today’s world, electronics are everywhere. From smartphones to medical devices, they power modern life. But these devices face a hidden challenge: electromagnetic interference (EMI). This interference can disrupt their performance or even cause them to fail. That’s where EMI/EMC filters come in. These filters ensure electronics work reliably by blocking unwanted signals.As technology advances, the need for these filters grows. For example, the EMI/EMC filters market is expected to nearly double, from $1.5 billion to $2.8 billion by 2032. The rise of 5G, with higher frequencies and faster data rates, brings more interference. Smaller devices also demand compact filters with high performance. Without these filters, modern electronics would struggle to keep up with the demands of 2025.Understanding EMI and EMCWhat is electromagnetic interference (EMI)?Electromagnetic interference, or EMI, occurs when unwanted electromagnetic signals disrupt the normal operation of electronic devices. These signals can come from various sources, such as power lines, motors, or even other electronic devices. For example, when you hear static on your radio while using a nearby hairdryer, that’s EMI in action.Recent studies indicate that the high-speed switching of SiC MOSFETs can lead to significant EMI issues due to the interaction with parasitic components in the circuit. The primary sources of EMI are linked to rapid changes in voltage and current (dv/dt and di/dt), which generate high-frequency noise. Additionally, the use of passive filters with high insertion loss is recommended to mitigate conducted EMI noise in motor drive control systems.EMI can be classified into two types: conducted and radiated. Conducted EMI travels through wires or cables, while radiated EMI spreads through the air. Both types can interfere with sensitive electronics, making EMI/EMC Filters essential for maintaining device performance.What is electromagnetic compatibility (EMC)?Electromagnetic compatibility, or EMC, ensures that electronic devices can operate without causing or experiencing interference. In simple terms, EMC means your devices can work together without disrupting each other. For instance, your smartphone and Wi-Fi router can function simultaneously without interference because they meet EMC standards.Achieving EMC involves designing devices that emit minimal electromagnetic noise and can resist external interference. However, this process can be challenging.ChallengeDescriptionHigh CostsSignificant expenses for SMEs in acquiring and maintaining EMC testing facilities.Complexity of TestingIncreased operational costs due to the intricate nature of EMC testing procedures.Shortage of Skilled ProfessionalsLack of qualified personnel leads to delays and inefficiencies in testing processes.Demand for ComplianceGrowing need for adherence to stringent EMC regulations in sectors like automotive and telecommunications.How EMI and EMC impact electronic devicesEMI and EMC directly affect the reliability and functionality of electronic devices. EMI can cause malfunctions, data loss, or even permanent damage to sensitive components. For example, in medical equipment, EMI could disrupt life-saving devices like pacemakers.On the other hand, poor EMC design can lead to devices interfering with each other. Imagine a scenario where your car’s navigation system stops working because of interference from its entertainment system. This is why EMI/EMC Filters play a critical role in ensuring devices perform reliably, especially in today’s interconnected world.What Are EMI/EMC Filters?Definition and purpose of EMI/EMC filtersEMI/EMC filters are specialized components designed to manage electromagnetic interference and ensure electromagnetic compatibility in electronic devices. These filters act as barriers, preventing unwanted signals from disrupting the operation of your devices. They also help manufacturers meet EMC standards, which are essential for certifying products as safe and reliable.Without these filters, devices could emit excessive electromagnetic noise or fail to withstand external interference. For example, a poorly designed electronic device might interfere with nearby equipment, causing malfunctions. EMI/EMC filters ensure that your devices operate effectively within their electromagnetic environment, making them indispensable in modern electronics.Tip: If you're designing or using electronic devices, always check for EMC compliance. It ensures your devices won't disrupt others or be disrupted themselves.How EMI/EMC filters suppress interferenceEMI/EMC filters suppress interference by controlling the frequency components of signals within electronic circuits. They block unwanted noise while allowing desired signals to pass through. This process enhances the performance of your devices and ensures they function reliably.Here are some common configurations used in EMI/EMC filters:Feed-through capacitors: The simplest form, ideal for basic noise suppression.L-circuit filters: Combine inductors and capacitors for effective filtering.PI-circuit filters: Divert noise at high-impedance nodes.T-circuit filters: Suppress noise at low-impedance nodes.Filter TypeFunctionalityLow-Pass FiltersStop high-frequency noise from entering or leaving a system.Feed-Through CapacitorSimplest form of EMI filter, consisting of a single component.L-Circuit FilterA basic configuration that uses inductors and capacitors to filter noise.PI-Circuit FilterCombines capacitors and inductors to create a low-impedance path for noise at high-Z nodes.T-Circuit FilterDesigned for low-Z nodes, using inductors to suppress noise effectively.By placing these filters between circuits, you can effectively suppress conducted and radiated interference. This suppression minimizes disruptions and ensures your devices perform as intended.The role of EMI/EMC filters in ensuring device reliabilityEMI/EMC filters play a critical role in protecting sensitive electronics from electromagnetic interference. High levels of electrical noise can cause data loss, malfunctions, or even complete device failure. These filters act as shields, limiting the penetration of noise signals and safeguarding your devices.For instance, in medical equipment, EMI filters prevent interference that could disrupt life-saving devices like pacemakers. In industrial machinery, they ensure smooth operation by blocking noise from motors and power lines. The global EMI filters market, valued at $274.5 million in 2022, highlights their importance. With a projected growth rate of 4.1% annually, the market is expected to reach $392.1 million by 2031.Note: Investing in high-quality EMI/EMC filters not only boosts device reliability but also reduces maintenance costs and downtime.Key Components of EMI/EMC FiltersCapacitors: Their role in filtering high-frequency noiseCapacitors are essential in EMI/EMC Filters because they filter out high-frequency noise from electronic circuits. They work by creating a low-impedance path for unwanted signals, diverting them away from sensitive components. You’ll often find capacitors in power lines, where they decouple common-mode noise generated by switching power supplies (SMPS).Different types of capacitors serve specific purposes:X-capacitors: These inhibit differential mode interference, which occurs between two conductors.Y-capacitors: These filter common-mode noise, which flows between a conductor and ground.Decoupling capacitors also stabilize voltage levels by acting as local energy reservoirs. They provide current during transient conditions, ensuring a steady DC supply. This minimizes crosstalk in digital circuits, keeping your devices running smoothly.Inductors: How they block unwanted signalsInductors are another critical component in EMI/EMC Filters. They block unwanted signals by resisting changes in current. When high-frequency noise tries to pass through, the inductor creates a magnetic field that opposes the current flow, effectively filtering out the interference.The effectiveness of an inductor is often measured by its insertion loss. This parameter shows how much noise the inductor removes from the circuit. Engineers also use S-parameter measurements, like the transmission coefficient (S21), to evaluate how well the inductor blocks unwanted signals. These measurements ensure the filter performs as expected in real-world conditions.Resistors: Their contribution to damping and stabilityResistors play a supporting role in EMI/EMC Filters by providing damping and stability. They help control the oscillations that can occur when capacitors and inductors interact. By dissipating excess energy as heat, resistors prevent voltage spikes and ensure the filter operates reliably.In addition, resistors improve the overall performance of the filter by reducing the risk of resonance. This makes them indispensable in maintaining the stability of electronic circuits, especially in high-frequency applications.Tip: When designing EMI/EMC Filters, consider the specific noise profile of your application. This helps you choose the right combination of capacitors, inductors, and resistors for optimal performance.Ferrite beads: Reducing high-frequency noise in circuits.Ferrite beads are small but powerful components that help reduce high-frequency noise in electronic circuits. You’ll often find them in EMI/EMC Filters, where they act as barriers to unwanted signals. These beads are made from ferrite, a magnetic material that absorbs and dissipates high-frequency noise as heat.When you place a ferrite bead on a wire or cable, it creates a choke point for electromagnetic interference. High-frequency noise encounters resistance, while low-frequency signals pass through unaffected. This makes ferrite beads ideal for suppressing noise in power lines, USB cables, and audio circuits.Ferrite beads come in various shapes and sizes, each designed for specific applications. For example, cylindrical beads are common in power cords, while clip-on beads are used for retrofitting existing cables. Choosing the right ferrite bead depends on the frequency range and noise level of your circuit.Tip: When selecting ferrite beads, check their impedance at the target frequency. Higher impedance means better noise suppression.Varistors: Protecting against voltage spikes.Varistors are essential for protecting electronic devices from voltage spikes. These components act like electrical safety valves, absorbing excess energy during sudden surges. You’ll often see them in EMI/EMC Filters, where they safeguard sensitive circuits from damage.Varistors exhibit sharp voltage breakdown characteristics, similar to back-to-back Zener diodes. Multilayer varistors (MLVs) are particularly effective because they can withstand thousands of strikes at full rated peak current without degrading. Their response time is less than one nanosecond, making them ideal for fast voltage spike protection.Modern MLVs also feature reduced self-inductance, which minimizes voltage overshoot during spikes. This improvement ensures reliable performance in high-speed circuits. You’ll find varistors in applications ranging from consumer electronics to industrial machinery, where they protect against sudden power fluctuations.Key advantages of varistors:Symmetrical voltage breakdown for consistent protection.High durability under repeated surges.Ultra-fast response time for immediate action.Reduced self-inductance for better performance.Note: Always choose varistors with a voltage rating slightly higher than your circuit’s operating voltage. This ensures optimal protection without interfering with normal operation.How EMI/EMC Filters WorkThe basic working principle of EMI/EMC filtersEMI/EMC filters work by suppressing electromagnetic noise in electronic circuits. They allow desirable currents to flow while diverting unwanted currents to the ground. These filters are typically low-pass filters, meaning they let lower frequencies pass through while blocking higher frequencies that cause interference. This ensures that your devices operate without disruptions from external noise.To achieve this, EMI/EMC filters use passive components like capacitors and inductors. Capacitors create a low-impedance path for high-frequency noise, directing it away from sensitive components. Inductors, on the other hand, resist changes in current, blocking high-frequency signals. Together, these components form LC circuits that filter out harmful noise while allowing the desired signals to pass.Key principles of EMI/EMC filters:Suppress electromagnetic noise through conduction.Divert unwanted currents to the ground or back to the source.Allow AC line frequencies to pass while blocking harmful high frequencies.For example, in DC motors, EMI filters act as bypass components. They allow DC current to flow without affecting the motor's performance. At the same time, they reduce internal EMI through field cancellation, ensuring smooth operation.How filters suppress conducted and radiated interferenceEMI/EMC filters are designed to tackle two types of interference: conducted and radiated. Conducted interference travels through wires or cables, while radiated interference spreads through the air. These filters suppress both types by using a combination of capacitors, inductors, and other components.Conducted interference is often addressed by placing capacitors between power lines and the ground. For instance, Y-capacitors are highly effective in reducing common-mode noise, which flows between a conductor and the ground. Inductors are also used to block high-frequency noise in power lines, ensuring that only the desired signals reach your devices.Radiated interference, on the other hand, is suppressed by creating barriers that absorb or redirect electromagnetic waves. Ferrite beads, for example, are commonly used to reduce high-frequency noise in cables. They create a choke point for interference, allowing low-frequency signals to pass through while blocking unwanted noise.Frequency (MHz)Capacitor Value (pF)Inductor Value (nH)Insertion Loss Requirement30> 86< 327< 1167> 30< 30< 1At 30 MHz, a 470pF Y-capacitor shows lower impedance, enhancing EMI suppression. At 167 MHz, a 100pF Y-capacitor demonstrates superior performance. These components effectively reduce both conducted and radiated EMI across various frequency bands, ensuring reliable device operation.The importance of proper placement and designThe placement and design of EMI/EMC filters play a crucial role in their effectiveness. Improper placement can lead to reduced performance or even failure to suppress interference. To optimize filter performance, you need to understand the type of interference and the frequency behavior of your circuit.For example, placing filters close to the source of interference minimizes the distance that noise can travel. This reduces the risk of interference affecting other components. Additionally, designing filters with the right combination of capacitors, inductors, and resistors ensures that they target the specific frequency range of the noise.Simulation tools can also help you optimize filter design. By accounting for parasitic elements, these tools allow you to predict how the filter will perform in real-world conditions. This approach not only improves performance but also reduces development time and costs.Tips for effective filter placement and design:Place filters close to the source of interference.Use simulation tools to optimize performance.Choose components based on the specific noise profile of your application.Proper placement and design ensure that EMI/EMC filters meet product certification standards. They also enhance device reliability, making them an essential part of modern electronics.Practical Applications of EMI/EMC FiltersImage Source: unsplashEMI/EMC filters in consumer electronics (e.g., smartphones, laptops)You rely on consumer electronics like smartphones and laptops every day. EMI/EMC filters ensure these devices perform reliably by eliminating electromagnetic noise. In smartphones, these filters prevent signal degradation caused by nearby RF transmitters. This ensures clear and uninterrupted calls, even in environments with multiple electronic devices. Similarly, laptops use these filters to maintain stable Wi-Fi connections and prevent interference from power supplies. Without EMI/EMC filters, your devices would struggle to deliver the seamless experience you expect.Key benefits of EMI/EMC filters in consumer electronics:Eliminate electromagnetic noise for better performance.Prevent signal degradation in mobile devices.Ensure uninterrupted connectivity in laptops and tablets.Their role in industrial equipment and machineryIn industrial settings, EMI/EMC filters play a critical role in maintaining equipment performance. Imagine a building materials distribution center where unexplained malfunctions disrupt operations. Engineers discovered that external noise currents were interfering with electrical systems. By installing ground line noise filters, they reduced emissions and restored equipment reliability. This example highlights how EMI/EMC filters protect industrial machinery from electromagnetic interference, ensuring smooth and efficient operations.Real-world example:A building materials company faced equipment malfunctions due to noise currents.Engineers identified interference sources through electromagnetic testing.Ground line noise filters resolved the issue, improving performance.Applications in automotive and aerospace industriesModern vehicles and aircraft rely heavily on electronics, making EMI/EMC filters essential. In automotive applications, the integration of advanced systems like infotainment, navigation, and safety features creates unique challenges. EMI/EMC filters ensure these systems work together without interference. Aerospace industries face even stricter requirements due to safety regulations. Filters help meet these standards by suppressing electromagnetic noise and ensuring reliable operation of critical systems.Key considerations for automotive and aerospace applications:Dual-line EMI filters are evaluated across wide frequency ranges for effectiveness.Compliance with stringent EMI/EMC standards ensures safety and product integrity.Filters address challenges from increased electronic integration in vehicles and aircraft.Tip: Always ensure your automotive or aerospace devices comply with EMI/EMC standards to avoid legal issues and maintain reliability.Importance of EMI/EMC Filters in 2025Ensuring compliance with global regulationsIn 2025, meeting global regulations for electromagnetic compatibility has become a critical requirement for electronic devices. You must ensure your devices comply with standards like the EU EMC Directive and FCC Part 15 to avoid costly penalties and maintain market access. These regulations demand that devices limit electromagnetic emissions and resist external interference. EMI/EMC Filters play a vital role in achieving this compliance by suppressing unwanted noise and ensuring devices meet strict testing criteria.RegulationDescriptionImpact on ManufacturersEU EMC DirectiveRequires devices to limit emissions and resist interference.Demands high-performance filters and rigorous testing.FCC Part 15Sets emission limits for devices in the US.Essential for market entry; requires robust quality checks.Financial ImpactsNon-compliance leads to recalls and legal liabilities.Losses can reach up to 10% of annual revenue.By integrating EMI/EMC Filters into your designs, you can ensure compliance, avoid financial risks, and maintain your reputation in competitive markets.Improving device performance and user experienceElectromagnetic interference can degrade the performance of your devices, leading to poor user experiences. EMI/EMC Filters enhance device reliability by blocking unwanted signals and maintaining signal integrity. For example, in smartphones, these filters prevent call drops and improve data speeds. In industrial machinery, they ensure smooth operations by reducing noise from motors and power lines.You can also improve user satisfaction by using filters to eliminate disruptions in wireless communication. Devices with robust EMI/EMC filtering deliver consistent performance, even in environments with high electromagnetic noise. This reliability builds trust and keeps users coming back to your products.Supporting the growth of IoT and 5G technologiesThe rise of IoT and 5G technologies has created a surge in demand for EMI/EMC Filters. As you connect more devices to the internet, the risk of interference increases. Filters ensure these devices communicate seamlessly without disrupting each other. In the automotive industry, the growing complexity of electronic systems has made EMI filtering essential for meeting global standards.The communication sector, driven by 5G, now dominates the surface mount filter market. High-performance filters are critical for maintaining signal integrity in wireless networks. As IoT and 5G expand, the demand for EMI/EMC Filters will continue to grow, making them indispensable for modern technology.EMI/EMC Filters are vital for ensuring the reliability of modern electronics. They protect devices from electromagnetic interference, allowing them to function smoothly in complex environments. Components like capacitors, inductors, and ferrite beads work together to suppress noise and maintain signal integrity. These filters also help meet global standards, making them essential for compliance.The growing integration of electronics in connected vehicles, smart homes, and high-speed data systems highlights their importance. The market for EMI/EMC Filters is expected to grow significantly from 2025 to 2033, driven by advancements in materials and the demand for efficient filtering solutions. As technology evolves, these filters will remain indispensable for innovation and performance.FAQ1. What is the difference between EMI and EMC?EMI refers to unwanted electromagnetic signals that disrupt devices. EMC ensures devices work without causing or experiencing interference. You need EMC-compliant devices to avoid disruptions caused by EMI.2. How do EMI/EMC filters improve device performance?Filters block unwanted signals and reduce noise. This ensures your devices operate smoothly, maintain signal integrity, and avoid malfunctions caused by interference.3. Can EMI/EMC filters be used in wireless devices?Yes, filters suppress interference in wireless devices like smartphones and routers. They ensure stable connections and prevent signal degradation caused by electromagnetic noise.4. Are EMI/EMC filters necessary for IoT devices?Absolutely! IoT devices rely on seamless communication. Filters eliminate interference, ensuring reliable data transfer and uninterrupted operation in connected environments.5. How do I choose the right EMI/EMC filter for my application?Consider your device’s noise profile and operating frequency. Match the filter’s specifications to your needs. Use simulation tools to optimize performance before installation.Tip: Consult an expert if you’re unsure about filter selection.

What is a coupling capacitor?In electronics, capacitive coupling is a type of electronic coupling, which uses capacitance between circuits to transfer energy. This coupling design can produce expected effects, and may also produce some accidental effects. Capacitive coupling usually involves placing capacitors in series circuits to achieve signal coupling.Next, this blog will briefly introduce you the basic information of coupling capacitors, mainly from the following six aspects: definition, coupling, decoupling, coupling mode, principle, and function.What is Coupling Capacitor?CatalogI Definition of coupling capacitorII CouplingIII DecouplingIV Coupling method4.1 Direct coupling4.2 Common impedance coupling4.3 Capacitive coupling4.4 Electromagnetic induction coupling4.5 Radiation coupling4.6 Leakage couplingV Working Principle of Coupling CapacitorVI The role of capacitive couplingFAQI Definition of coupling capacitorCoupling capacitance, also known as electric field coupling or electrostatic coupling, is a coupling method due to the existence of distributed capacitance.Coupling capacitors make the two systems of strong and weak currents coupled and isolated by capacitors, provide high-frequency signal paths, prevent low-frequency currents from entering the weak current system, and ensure personal safety. In addition to the above functions, the coupling capacitor with voltage extraction device can also extract power frequency voltage for protection and reclosing use, and play the role of a voltage transformer.Coupling capacitor II CouplingCoupling refers to the process of signal transmission from the first stage to the second stage, and usually refers to AC coupling when it is not specified.From the circuit point of view, it can always be divided into the driving power supply and the driven load. If the load capacitance is relatively large, the drive circuit must charge and discharge the capacitance to complete the signal jump. When the rising edge is relatively steep, the current is relatively large, so that the drive current will absorb a large power supply current. The inductance and resistance (especially the inductance on the chip pins will bounce). Compared with normal conditions, this current is actually a kind of noise, which will affect the normal operation of the previous stage. This is coupling.Red WIMA CAPIII DecouplingDecoupling refers to taking further filtering measures to the power supply to remove the influence of mutual interference between the two levels of signals through the power supply.The coupling constant refers to the time constant corresponding to the product of the coupling capacitance value and the second-stage input impedance value.The purpose of decoupling1. Remove the high-frequency ripple in the power supply, and cut off the high-frequency signal of the multi-stage amplifier through the crosstalk path of the power supply;2. When working with a large signal, the circuit's demand for power increases, causing power fluctuations, and the influence of power fluctuations on the input stage/high voltage gain stage when the large signal is reduced by decoupling;3. Form a floating ground or floating power supply, and complete the coordination of each part of the ground or power supply in a complex system. The high-frequency switching noise generated by the active device during switching will propagate along the power line. The main function of the decoupling capacitor is to provide a local DC power supply to the active device to reduce the propagation of switching noise on the board and to guide the noise to the ground.WEST-CAPIV Coupling methodThe interference signal generated by the interference source causes electromagnetic interference to the electronic control system through a certain coupling channel. The coupling method of interference is nothing more than acting on the electronic control system through wires, spaces, common lines, etc. There are mainly the following:4.1 Direct couplingDirect coupling is the most direct way of interference intrusion, and it is also the most common way in the system. For example, interference signals directly invade the system through wires and cause interference to the system. For this coupling method, filtering and decoupling can be used to effectively suppress the introduction of electromagnetic interference signals. 4.2 Common impedance couplingCommon impedance coupling is a common coupling method. It often happens when the currents of two circuits have a common path. Common impedance coupling has two types: common ground and power supply impedance. To prevent this coupling, the coupling impedance should be close to zero, so that there is no common impedance between the interference source and the interfered object. 4.3 Capacitive couplingCapacitive coupling, also known as electric field coupling or electrostatic coupling, is a coupling method due to the existence of distributed capacitance. 4.4 Electromagnetic induction couplingElectromagnetic induction coupling is also called magnetic field coupling. It is a coupling method induced by the electromagnetic field in the internal or external space. The common method to prevent this coupling is to shield devices or circuits that are susceptible to interference. 4.5 Radiation couplingThe electromagnetic field radiation can also cause interference coupling, which is an irregular interference. This kind of interference is easily transmitted to the system through the power line. In addition, when the signal transmission line is long, they can radiate and receive interference waves, which is called the antenna effect. 4.6 Leakage couplingThe so-called leakage coupling is resistive coupling. This interference often occurs when the insulation is reduced.Black beautyV Working Principle of Coupling CapacitorWhen the capacitor is connected to the AC circuit, the voltage of the circuit connected to a pin gradually rises, and gradually accumulates charge on the plate where it is located. When the voltage of the circuit connected to the pin drops, the charge accumulated when the potential is high returns to the circuit.TCC V-CAPThe same goes for the other end. The capacitor is insulated, and no current flows through the entire capacitor, but the phenomenon that it accumulates and releases charges as the potential rises and falls, which makes people mistakenly believe that there is current passing. Therefore, it can isolate the DC.The AC signal is coupled to the following circuit components in the form of increasing and decreasing potential at both ends. Capacitors have the characteristics of passing AC and blocking DC. As a coupling capacitor, its function is to allow AC signals to pass normally, while blocking the DC current of the previous amplifier circuit, so that it will not affect the operating point of the next amplifier circuit.Why can the capacitor make the AC current flow and the DC current cannot flow? The two plates of the capacitor can store charge but do not form a loop. The DC current can charge the capacitor, but when the voltage across the capacitor is the same as the power supply voltage, the circuit stabilizes. Therefore, no current will flow; the positive half cycle of the alternating current charges the capacitor, and the negative half cycle first discharges the capacitor. Such continuous charging and discharging are equivalent to current flowing through the capacitor to form a path. VI The role of capacitive couplingThe function of capacitive coupling is to transfer the AC signal from the previous stage to the next stage.Coupling methods include direct coupling and transformer coupling. The direct coupling efficiency is the highest, and the signal is not distorted. However, the adjustment of the working points of the front and rear stages is more complicated and involves each other. In order to prevent the working point of the latter stage from being affected by the previous stage, it is necessary to separate the former stage from the latter stage in terms of direct current.SPRAGUE VQ V-CAPAt the same time, the AC signal can be smoothly transmitted from the previous stage to the next stage. At the same time, the way to accomplish this task is to use capacitor transmission or transformer transmission to achieve. They can transmit AC signals and block DC, so that the working points of the front and rear stages are not involved in each other. But the difference is that when using a capacitor to transmit, the phase of the signal will be delayed, and when using a transformer, the high-frequency component of the signal will be lost.In general, capacitors are often used as coupling elements for small signal transmission, and transformers are often used as coupling elements for large signal or strong signal transmission. FAQ 1. What is meant by coupling capacitor?Coupling capacitors (or dc blocking capacitors) are use to decouple ac and dc signals so as not to disturb the quiescent point of the circuit when ac signals are injected at the input. Bypass capacitors are used to force signal currents around elements by providing a low impedance path at the frequency.2. How does a coupling capacitor work?Definition: A capacitor that is used to connect the AC signal of one circuit to another circuit is known as a coupling capacitor. ... On the o/p end, we get the AC signal. So a coupling capacitor is placed between two circuits so that AC signals supplies while the DC signal is blocked.3. What is the need of coupling capacitor?Coupling capacitors are essential components in amplifier circuits. They are used to prevent interference of a transistor's bias voltage by AC signals. In most amplifier circuits, this is achieved by driving the signal to the base terminal of a transistor through a coupling capacitor.4. What is coupling and decoupling capacitor?A decoupling capacitor is a capacitor used to decouple one part of an electrical network (circuit) from another. ... In analog circuits, a coupling capacitor is used to connect two circuits such that only the AC signal from the first circuit can pass through to the next while DC is blocked.5. Why decoupling capacitor is used?A decoupling capacitor acts as a local electrical energy reservoir. Capacitors, like batteries, need time to charge and discharge. When used as decoupling capacitors, they oppose quick changes of voltage. ... Decoupling capacitors are used to filter out voltage spikes and pass through only the DC component of the signal. 6. How do I choose a coupling capacitor?A coupling capacitor is best selected so that its impedance is as low as possible at the frequency of interest. The impedance magnitude at any frequency is easily calcu- lated as: Since the net reactance is zero at the capaci- tor's FSR, the total impedance will be equal to the ESR at this frequency. 7. What is the value of coupling capacitor?C is the coupling cap value, w is the angular frequency 2*pi*f with f the frequency in Hertz. Units of resistance Ohms, capacitance Farads. The reason for this is because the three components form a voltage divider and the output only appears across R2 the output resistor. 8. What is coupling capacitor and bypass capacitor?Coupling capacitors (or dc blocking capacitors) are use to decouple ac and dc signals so as not to disturb the quiescent point of the circuit when ac signals are injected at the input. Bypass capacitors are used to force signal currents around elements by providing a low impedance path at the frequency. 9. What happens when coupling capacitor is removed?Since capacitor blocks DC, former stage do not affect DC biasing of succeeding stage. Disadvantage of coupling capacitor is, it put limit on low frequency response of the amplifier. Another disadvantage is, capacitor coupled amplifier, can not be used for amplifying DC signal. 10. How do you calculate the value of coupling capacitor?Measure, calculate or determine from a manufacturer's data sheet the input impedance of the circuit to which the coupling capacitor is connected. Multiply this number by 1/10 to find the minimum value of the coupling capacitor's impedance.

FPGA (Field-Programmable Gate Array), it is the product of further development on the basis of PAL, GAL, CPLD and other programmable devices. It appears as a kind of semi-custom circuit in the field of application specific integrated circuit (ASIC). It not only solves the shortage of custom circuit, but also overcomes the shortcoming of limited number of gates in the original programmable devices.What is an FPGA, and how does it compare to a microcontroller?CatalogI. What is FPGA?II. Principles of FPGAs III. FPGA Pros & ConsIV. FPGA Chip StructureV. FPGA FeaturesFAQI. What is FPGA?FPGA (Field Programmable Gate Array) is a product of further development on the basis of programmable devices such as PAL and GAL. It emerged as a semi-custom circuit in the field of application-specific integrated circuits (ASIC), which not only solves the deficiencies of custom circuits, but also overcomes the shortcomings of the limited number of gate circuits of the original programmable devices.II. Principles of FPGAs FPGA adopts the concept of Logic Cell Array (LCA), which consists of Configurable Logic Block (CLB), Input Output Block (IOB) and Internal Interconnect. Three parts. FPGAs are programmable devices with a different structure than traditional logic circuits and gate arrays (such as PAL, GAL and CPLD devices). The logic of the FPGA is implemented by loading programmed data into the internal static memory cell, and the values stored in the memory cell determine the logic function of the logic cell and the connection between the modules or between the modules and the I/O. The value stored in the memory cell determines the logical function of the logic unit and the way the modules are linked to each other or to the I/O, and ultimately determines the functions that the FPGA can achieve.III. FPGA Pros & Cons - The Pros of FPGAs:(1) FPGAs consist of hardware resources such as logic cells, RAM, multipliers, etc. By organizing these hardware resources rationally, hardware circuits such as multipliers, registers, address generators, etc. can be implemented.(2) FPGAs can be designed by using block diagrams or Verilog HDL, from simple gate circuits to FIR or FFT circuits.(3) FPGAs can be infinitely reprogrammed, loading a new design solution in a few hundred milliseconds, reducing hardware overhead with reconfiguration.(4) The operating frequency of the FPGA is determined by the FPGA chip as well as the design, and can be modified by modifying the design or replacing it with a faster chip to meet certain demanding requirements (of course, the operating frequency is not unlimited and can be increased, but is governed by current IC processes and other factors).  - The Cons of FPGAs:(1) All functions of FPGAs rely on hardware implementation and cannot implement operations such as branching conditional jumping.(2) FPGAs can only implement fixed-point operations.To conclude: FPGAs rely on hardware to implement all functions and can be compared to dedicated chips in terms of speed, but there is a big gap in design flexibility compared to general purpose processors.IV. FPGA Chip StructureMainstream FPGA is still based on look up table technology, has far exceeded the basic performance of previous versions, and integrates common features (such as RAM, clock management and DSP). FPGA chips have seven main parts: programmable input/ output unit, basic programmable logic unit, complete clock management, embedded block RAM, rich wiring resources, embedded bottom functional unit and embedded special hardware module.The functions of FPGA chip structure are as follows:1. Programmable Input and Output BlockThe programmable input/ output block is referred to as I/ O port. It is the interface part between the chip and the external circuit, which can drive and match the input/ output signals under different electrical characteristics. I/ O in FPGA is classified by group, and each group can support different I/ O standards independently. With the flexible configuration of the software, different electrical standards and I/ O physical characteristics can be met, the drive current can be adjusted, and the frequency of I/ O port of the and pull-up resistor and pull-down resistor can be changed, so that the frequency of the I/ O port can be higher and higher. Some high-end FPGA can support data rate up to 2Gbps through DDR register.Fig 1. IOB Internal Structure DiagramThe external input signal can be read into the FPGA through the memory cell of the IOB module, or directly written into the inside of the FPGA. When the external input signal passes through the memory cell of the IOB module read into the inside of the FPGA, the requirement of hold time  can be reduced, which usually the windows default is 0.In order to facilitate management and adapt to a variety of electrical standards, FPGA's IOB is divided into several banks, each bank interface standard is determined by its interface voltage VCCO, in addition, a bank can only have one VCCO, but each bank VCCO can be different. Only ports with the same electrical standard can be connected together, and the same VCCO voltage is the basic requirement of the interface standard.2. Configurable Logic Block (CLB)CLB is the basic logical unit within the FPGA. The actual number and characteristics of CLBs vary depending on the device, but each CLB contains a configurable switch matrix that consists of 4 or 6 inputs, some lectotype circuits (multiplexers, etc.) and flip-flops. The switch matrix is highly flexible and can be configured to work with combinational logic, shift registers, or RAM. In Xilinx's FPGA device, the CLB consists of multiple (usually 4 or 2) identical Slices and additional logic. Each CLB module be used to realize combinational logic and sequential logic, and it can also be configured as distributed RAM and distributed ROM.Fig 2. CLB Structure DiagramSlice is a basic logical unit defined by Xilinx. A Slice consists of two 4-input functions, carry logic, arithmetic logic, storage logic and function multiplexer. Arithmetic logic includes a  XORG and a MULTAND. XORG enables a Slice to implement the full operation of 2bit, and MULTAND improves the efficiency of multipliers. Carry logic consists of a dedicated carry signal and a function multiplexer for fast arithmetic addition and subtraction operations; 4-input functions generator is used to implement the 4-input LUT, distributed RAM or 16-bit shift register. Carry logic includes two fast carry chains to improve the processing speed of the CLB module.Fig 3. Inputting Slice Structure Diagram3. Digital Clock Management (DCM)Most of the industry's FPGA offer digital clock management. FPGA offers digital clock management and phase loop locking. Phase loop locking can provide accurate clock synthesis, reduce jitter and achieve filtering.4. Block Random Access Memory (BRAM)Most FPGAs have embedded block RAM, which greatly extends the applications and flexibility of the FPGA. The block RAM may be configured as a single-port RAM, a dual-port RAM, a content address memory (CAM), and a common storage structure such as a FIFO. CAM memory has a comparison logic in each of its internal memory cells, the data written into the CAM will be compared with each of the data in the interior, and the address of all data that is the same as the port data, so that there is a wide range of address switches in the route application. In addition to the block RAM, the LUT in the FPGA can be flexibly configured as a RAM, a ROM, and a FIFO. In practical application, that number of block RAM in the internal block of the chip is also an important factor in the chip selection.The capacity of the monolithic RAM is 18k bits, that is, the bit width is 18 bits and the depth is 1024. It can change the bit width and depth according to the need, but two principles must be satisfied: firstly, the modified capacity (bit width depth) cannot be greater than 18k bits; Second, the maximum bit width cannot exceed 36 bits. Of course, it is possible to concatenate multiple blocks of RAM to form a larger RAM, which is limited only by the number of RAM blocks in the chip and is no longer constrained by the above two principles.5. Wiring SourceAll the parts are connected with wiring resources in the FPGA, and the length and process of the connection determine the driving ability and the transmission speed of the signal on the wire. There are abundant wiring resources in the FPGA chip, according to the process and length, width and distribution position, which are divided into 4 different categories. First is the global routing resource, which is used for the internal global clock and the global reset/ position routing. Second is the long line resource, which is used to complete the wiring of the high-speed signal and the second global clock signal between chip banks. Third is short-line resources, which are used to perform logical interconnection and cabling between basic logical units. Fourth is a distributed wiring resource, which is used as control signal lines for a proprietary clock or a reset.In practice, the designer does not need to select the routing resources directly, and the layout scheduler can automatically select the better routing resources according to the topology of the input logical grid table and constraint conditions to connect each module unit. In essence, the use of routing resource types has a close and direct relationship with the results of the design.6. Underlying Built-in Function The underlying built-in function mainly refers to a DLL (Delay Locked Loop), a PLL (Phase Locked Loop), a DSP, and a CPU, which belong to core softcore. The more and more built-in functional units make the single-chip FPGA a system-level design tool, so that it has the capability of joint design of hardware and software, and gradually turn to the SOC platform.DLL and PLL have similar functions, such as high-precision clock and low jitter frequency doubling and frequency division, duty cycle adjustment and phase shift, etc. Xilinx integrated the DLL, Altera made the PLL, Lattice combined both two, which can be easily managed and configured through IP core-generated tools on Lattice's new chip. Fig 4. Typical DLL module schematics7. Special Built-in Hard CoreThe embedded special hard core is relative to the soft core embedded in the bottom, which means that the hard core with strong processing ability of FPGA is equivalent to the ASIC. To improve FPGA performance, chip manufacturers integrate some dedicated hard cores on the chip. For example, to improve the multiplication speed of FPGA, special multipliers are integrated in the mainstream FPGA, and in order to match the communication bus and interface standard, a lot of high-end FPGA are integrated SERDES, which can achieve the receiving and dispatching speed of  Gbps. V. FPGA Features1) The ASIC circuit is designed by adopting the FPGA, and the user does not need to put the chip into production, so that a shared chip can be obtained.2) FPGA can be used as a trial sample of other fully customized or semi-custom ASIC circuits.3) There are rich flip-flops and I/ O pins within the FPGA.4) FPGA is one of the devices with the shortest design cycle, the lowest development cost and the least risk among ASIC circuits.5) FPGA adopts high-speed CMOS process, low power consumption, and can be compatible with CMOS and TTL.It can be said that FPGA chip is one of the best choices for small batch system to improve system integration and reliability.The working state of FPGA is set by the program stored in the on-chip RAM, so it is necessary to program the on-chip RAM when working. Users can use different programming methods according to different configuration modes.When the power is on, the FPGA chip reads the data from the EPROM into the on-chip programming RAM. After the configuration is completed, the FPGA enters the working state. After power off, FPGA internal logic disappears. Therefore, FPGA can be programmed repeatedly. And the programming of FPGA does not require a special programmer, a general-purpose EPROM or PROM programmer can meet the requirement. When you need to modify the FPGA functionality, just replace a piece of EPROM. In this way, the same piece of FPGA, with different programming data, can produce different circuit functions. Therefore, the use of FPGA is very flexible.FAQ 1. What is FPGA and why it is used?FPGA Basics: Architecture, Applications and Uses. The field-programmable gate array (FPGA) is an integrated circuit that consists of internal hardware blocks with user-programmable interconnects to customize operation for a specific application.2. Is FPGA faster than CPU?They also found that using custom FPGAs to implement the Rowhammer exploit would cause far more of the "bit flips" that they wanted to see. A FPGA can hit the data cell faster and more often than a CPU can do it meaning the FPGA causes more results to occur during an attack. It all goes faster when an FPGA is used.3. Are FPGAs dead?Yes, it's a dead end. If you enjoy creating hardware, RTL design targeting FPGAs is still a good choice (although there is a huge amount of effort here to make it more like creating software than hardware).4. What are FPGAs good for?FPGAs are particularly useful for prototyping application-specific integrated circuits (ASICs) or processors. An FPGA can be reprogrammed until the ASIC or processor design is final and bug-free and the actual manufacturing of the final ASIC begins. Intel itself uses FPGAs to prototype new chips.5. Is FPGA a microprocessor?Microprocessors are more complex than FPGAs. Microprocessors have fixed instructions while FPGAs don't. FPGAs and microprocessors are often mixed into a single package.6. What are the advantages of FPGA?FPGA advantages:Long-term availability.Updating and adaptation at the customer.Very short time-to-market.Fast and efficient systems.Acceleration of software.Real-time applications.Massively parallel data processing.7. Why is FPGA slow?FPGAs tend to get faster in max speed, but the limit actually has to do with process variation affecting static timing. The chips have to have a soultion that works on all of them. So you lose performance of the device to make sure any device will work with it. And as your design gets bigger it runs slower.8. What are the disadvantages of FPGA?Drawbacks or disadvantages of FPGA:The programming is not as simple as C programming used in processor based hardware. Moreover engineers need to learn use of simulation tools. ➨The power consumption is more and programmers do not have any control on power optimization in FPGA. No such issues in ASIC.9. Can FPGA replace CPU?There will always be a need for a general purpose CPU to run most things, and while you can implement a CPU on an FPGA, that gives you the worst of both worlds - no improvement from specialised hardware design, and you still need to pay the “FPGA tax”. So no, FPGAs will never replace CPUs.10. Why use an FPGA vs microcontroller?A FPGA can be used if the design requires complex logic and requires high processing ability and if the cost is comparable to the performance achieved. In case of a design that requires limited hardware, and is set to perform only some specific functions, then Microcontroller is preferred.

What is a resistor? In short, resistors are electronic components which have a specific, never-changing electrical resistance. The resistor's resistance limits the flow of electrons through a circuit. So in this article today, we will have a detailed discussion on resistors, which will present you as much as information about resistor as possible.I What is a Resistor?1.1 Brief IntroductionResistors are passive electrical components that limit electric current. This video explains in an easy way the most basic background to help you understand resistors and use them.A resistor refers to a two-terminal electronic element made of resistor material with a certain structure that can limit the current passing through the circuit. It is the most widely used component in electronic circuits, which usually form different series according to its power and resistance values. Its function in circuits is to regulate and stabilize current and voltage, that is,  used as shunt and voltage divider, or circuit matching load. According to the circuit requirements, it can also be used for negative feedback or positive feedback of amplifying circuit, voltage-current conversion, voltage or current protecting element when existing input overload. With the capacitor, it can form an RC circuit, which can be used as oscillation, filter, bypass, differential, Integral and time constant elements, etc. Those whose resistance values cannot be changed are called fixed resistors, and those with variable resistance values are called potentiometers or variable resistors. Some special resistors, such as thermistors, varistors, and sensitive elements, have a nonlinear relationship between voltage and current.1.2 Resistor and ResistanceThe resistor is a current limiting element in daily life. Resistance is a physical quantity describing the conductivity of a conductor, represented by R. Resistance is defined by the ratio of the voltage U at the two ends of the conductor and the current I passing through the conductor, that is, R=V/I. When the resistor is connected to the circuit, the resistor's resistance is fixed by two pins, which can limit the current to flow through the branch of the resistor. The resistance that cannot be changed is called a fixed resistor. In addition, a variable resistance is called a potentiometer or a variable resistor. The ideal resistor is linear, that is, the instantaneous current of the resistor is positive to the applied instantaneous voltage, for example, the variable-voltage resistor is used as a voltage divider. On a bare resistor, there are one or two removable metal contacts, and the contact position determines the resistance between any end of the resistor and the contact.  The terminal voltage and current have a definite function relation, and the two-terminal device which embodies the conversion of electric energy into other forms, represented by the letter R, and its unit is Ω. Devices such as light bulbs, heating wires, resistors, and so on can be expressed as resistor elements.The resistance value of the resistor is generally related to temperature, material, component length, and cross-section area. The physical quantity of measuring resistance affected by the temperature is the temperature coefficient, which is defined as the percentage of resistance value changing when the temperature rises 1℃. The main physical characteristic of resistors is transforming the electricity into heat energy, also the resistor can be said to be an energy dissipation element because the internal energy will be generated when current flows through it. Resistors usually act as a divider and shunt in a circuit. And for signals, both AC and DC signals can pass through resistors.In physics, resistance is a figure to indicate the magnitude of a conductor's hindrance to current. The greater the resistance of a conductor, the greater the resistance of the conductor to the current. Generally, different conductors have different resistances, in other words, resistance is a characteristic of the conductor itself. The resistance element is a kind of energy dissipation element which hinders the current. The stuff under the action of matter called resistive substance because of its blocking effect on the current. The resistor will lead to the change of the electron flux. When the voltage at both ends of the conductor is fixed, the larger the resistance, the smaller the current passing through, on the other hand, the smaller the resistance, the greater the current passing through. 1.3 Resistor BasicsThe resistor consists of three parts of a resistor body, a framework, and a lead-out end (the resistor body of the solid-core resistor is integrated with the framework), and the resistor body plays an important part in this electronic component. For a resistor body with a uniform cross-section, the resistance value is calculated by the following formula: ρ is the electrical resistivity (ohm-cm), L is the length (cm) of the resistor, and A is the cross-sectional area of the resistor (square centimeter).R=ρ× L/AThe thickness of the thin film resistor is very small and difficult to measure accurately, and ρ varies with the thickness values, so the constant related to the film material is regarded as the film resistance. In fact, it is the resistance of the square film, so it is also known as the square resistance. For homogeneous films, W is the width of the film (cm), in general, Rs should be in a limited range because large Rs will affect the stability of resistor performance. Therefore the cylindrical resistor is notched and the planar resistor uses the etching method of a detour to extend the range of resistance and to fine-tune the resistance.R=Rs×L/WThe volt-ampere characteristic is a graph that represents the relationship between the voltage and the current of the resistor terminal. When the voltage-current is proportional (representing a straight line), it is called a linear resistor, otherwise referred to as a non-linear resistor.The vertical coordinates of this diagram are current I and the transverse coordinates are voltage U. This graph is also called the current-voltage curve, more often is referred to as the volt-ampere characteristics curve. As we can see, the blue curve is a straight line passing through the origin, and its resistance does not change with the change of voltage and current, in fact, elements that satisfy this volt-ampere characteristic curve are called linear elements. On the other hand, for the red curve, we can see that it is a curve, its resistance value changes with the change of voltage and current.The main parameters used to characterize the resistance have nominal resistance, allowable deviation, rated power, load characteristic, resistor temperature coefficient, and so on.1.4 Resistor Operation TheoryOhm's lawThe behavior of an ideal resistor is dictated by the relationship specified by Ohm's law:V=I ∙ ROhm's law states that the voltage (V) across a resistor is proportional to the current (I), where the constant of proportionality is the resistance (R). For example, if a 300-ohm resistor is attached across the terminals of a 12-volt battery, then a current of 12/300 = 0.04 amperes flows through that resistor.Practical resistors also have some inductance and capacitance which affect the relation between voltage and current in alternating current circuits.In addition, linear or ohmic resistance meets Ohm's law, but nonlinear resistance does not satisfy Ohm's law.The nominal resistance is the design resistance of the sign on the resistor with a digital or color code. The units are Ω, KΩ, and MΩ. Resistance values are written according to standardized priority series, which correspond to allowable deviations.The electrical resistance of a resistor is measured in ohms. The symbol for an ohm is the greek capital-omega: Ω. The ohm (symbol: Ω) is the SI unit of electrical resistance, named after Georg Simon Ohm. An ohm is equivalent to a volt per ampere. Since resistors are specified and manufactured over a very large range of values, the derived units of milliohm (1 mΩ = 10−3 Ω), kilohm (1 kΩ = 103 Ω), and megohm (1 MΩ = 106 Ω) are also in common usage. For example, a 4,700Ω resistor is equivalent to a 4.7kΩ resistor, and a 5,600,000Ω resistor can be written as 5,600kΩ or (more commonly as) 5.6MΩ. 1.5 Resistor Electronic SymbolsNotation1Ω= 1 Ohms1 KΩ= 1 Kilo Ohms1 MΩ= 1 Mega Ohms1 GΩ= 1 Giga OhmsWhen the value can be expressed without a prefix (that is, multiplicator 1), an "R" is used instead of the decimal separator. For example, 1R3 indicates 1.3Ω, and 15R indicates 15Ω.Marking method for Resistance and Tolerance of Resistors：① Direct Scaling MethodThe resistance and error of the resistor are directly printed on the resistor by numbers and letters (no error is indicated as the tolerance ±20%). There are also manufacturers who use customary marking methods, such as:3Ω3Ⅰis represent the resistance 3.3Ω, tolerance is ±5%1 K 8 represents the resistance 1.8 KΩ, tolerance is ±20%5 M 1Ⅱis represent the resistance 5.1 MΩ, tolerance is ±10% ② Resistor Color Bands/CodesThis Physics video tutorial is explaining the fundamentals of color code for four colour bands in a carbon resistor.The color bands are coated on the resistor to indicate the nominal value of the resistor and the allowable tolerance. The corresponding values of various colors and the recognition rules of the color bands/codes of the reading principle of the fixed resistor are shown in the following figure.Four-band ResistorsIn the standard four-band resistors, the first two bands indicate the two most significant digits of the resistor’s value. The third band is a weight value, which multiplies the two significant digits by a power of ten.The final band indicates the tolerance of the resistor. The tolerance explains how much more or less the actual resistance of the resistor can be compared to what its nominal value is. No resistor is made to perfection, and different manufacturing processes will result in better or worse tolerances. For example, a 1kΩ resistor with 5% tolerance could actually be anywhere between 0.95kΩ and 1.05kΩ.Example: red-orange black gold=23*10^0=23Ω(±5%)Five-band and six-band ResistorsFive band resistors have a third significant digit band between the first two bands and the multiplier band. Five band resistors also have a wider range of tolerances available.Six band resistors are basically five band resistors with an additional band at the end that indicates the temperature coefficient. This indicates the expected change in resistor value as the temperature changes in degrees Celsius. Generally, these temperature coefficient values are extremely small, in the ppm range.Example: red blue green black brown=265*10^0=265Ω(±1%)ToleranceThe maximum tolerance between the actual resistance and the nominal resistance, represented by percentages. Commonly used are ±5%, ±10%, ±20%, precision is less than ±1%, high precision up to 0.001%. The accuracy is determined by both the tolerance and the irreversible resistance.Power RatingMaximum power dissipation allowed for continuous operation of resistors at rated temperature (maximum ambient temperature) tR. And the maximum operating voltage is also specified for each resistor, that is, the maximum operating voltage cannot be exceeded even if the resistance value is high.Identification of rated Power of ResistorsThe rated power of a resistor refers to the maximum power that a resistor is allowed to consume in a long-term continuous operation in a DC or AC circuit. There are two marking methods: the resistance above 2W is directly printed on the resistor body, and the resistance below 2W is represented by its own volume. When the resistance power is expressed on the circuit diagram, the following symbols are used: 1) Load CharacteristicWhen the working temperature is lower than tR, the resistor can not exceed its rated power, and the load power must be reduced when it exceeds tR. Each resistor has its own specified load characteristic. In addition, the load is allowed to be reduced accordingly at low pressure. Under pulse load, the average power of the pulse is much lower than the rated power, the load is according to the practical situation.2) Resistance Temperature CoefficientThe average relative variation of the resistance value at each change of 1℃ is expressed in terms of ppm/ ℃ within a specified range of ambient temperature. In addition to the above parameters, there are other technical indicators, such as nonlinearity (the extent to which the characteristics of the current and the applied voltage deviate from the linear relationship), the voltage coefficient (the relative rate of change of the voltage at which the voltage is applied, the relative rate of change of the volt resistance), current noise (the ratio of the effective value of the noise potential generated by the current flow in the resistor to the measured voltage, expressed by the current noise index), the high-frequency characteristic (due to the effect of the distributed capacitance and the distributed inductance in the resistor; a curve in which the resistance value decreases as the operating frequency increases; long-term stability (such as irreversible changes in resistance values affected by environmental conditions during long term use or storage).II Resistor CharacteristicsDependent on the application, the electrical engineer specifies different properties of the resistor. The primary purpose is to limit the flow of electrical current; therefore the key parameter is the resistance value. The manufacturing accuracy of this value is indicated with the resistor tolerance in percentage. Many other parameters that affect the resistance value can be specified, such as long-term stability or the temperature coefficient. The temperature coefficient, usually specified in high precision applications, is determined by the resistive material as well as the mechanical design.In high-frequency circuits, such as in radio electronics, the capacitance and inductance can lead to undesired effects. Foil resistors generally have a low parasitic reactance, while wire-wound resistors are amongst the worst. For accurate applications such as audio amplifiers, the electric noise must be as low as possible. This is often specified as microvolts noise per volt of applied voltage, for a 1 MHz bandwidth. For high-power applications, the power rating is important. This specifies the maximum operating power the component can handle without altering the properties or damage. The power rating is usually specified in free air at room temperature. Higher power ratings require a larger size and may even require heat sinks. Many other characteristics can play a role in the design specification. Examples are the maximum voltage or the pulse stability. In situations where high voltage surges could occur this is an important characteristic.Resistors in series and parallel ConnectionIn electronic circuits, resistors are very often connected in series or in parallel. A circuit designer might for example combine several resistors with standard values (E-series) to reach a specific resistance value. For series connection, the current through each resistor is the same and the equivalent resistance is equal to the sum of the individual resistors. For parallel connection, the voltage through each resistor is the same, and the inverse of the equivalent resistor value is equal to the sum of the inverse values for all parallel resistors. In the articles resistors in parallel and series, a detailed description of calculation examples is given. To solve even more complex networks, Kirchhoff’s circuit laws may be used.The Total resistance of resistors connected in series is the sum of each single individual resistance value.The total resistance of resistors connected in parallel is the reciprocal of the sum of the reciprocals of the individual resistors.As a special case of this equation: if you have just two resistors in parallel, their total resistance can be calculated with this slightly-less-inverted equation:Termination and MountingResistors will come in one of two termination types: through-hole or surface-mount. These types of resistors are usually abbreviated as either PTH (plated through-hole) or SMD/SMT (surface-mount technology or device).Through-hole resistors come with long, pliable leads which can be stuck into a breadboard or hand-soldered into a prototyping board or printed circuit board (PCB). These resistors are usually more useful in breadboarding, prototyping, or in any case where you’d rather not solder tiny, little 0.6mm-long SMD resistors. The long leads usually require trimming, and these resistors are bound to take up much more space than their surface-mount counterparts.The most common through-hole resistors come in an axial package. The size of an axial resistor is relative to its power rating. A common 1/2W resistor measures about 9.2mm across, while a smaller 1/4W resistor is about 6.3mm long.Surface-mount resistors are usually tiny black rectangles, terminated on either side with even smaller, shiny, silver, conductive edges. These resistors are intended to sit on top of PCBs, where they’re soldered onto mating landing pads. Because these resistors are so small, they’re usually set into place by a robot and sent through an oven where solder melts and holds them in place.III Resistor TypesMost types of the resistor are linear devices that produce a voltage drop across themselves when an electrical current flows through them because they obey Ohm’s Law, and different values of resistance produce different values of current or voltage. This can be very useful in Electronic circuits by controlling or reducing either the current flow or voltage produced across them we can produce a voltage-to-current and current-to-voltage converter.Resistors come in a variety of shapes and sizes. They might be through-hole or surface-mount. They might be a standard, static resistor, a pack of resistors, or a special variable resistor. The different types of resistors are discussed in the following section.1. Classified by Volt-ampere Characteristic*Linear resistors*Non-linear resistorsFor most conductors, at a certain temperature, the resistance is almost unchanged and is a certain value, the resistors having this kind of resistance is called a linear resistor. The resistors of some materials vary obviously with the current (or voltage) change, and the volt-ampere characteristic of them is a curve, which is called a nonlinear resistor. Under a given voltage (or current), the ratio of voltage to current is the static resistance at the working point, and the slope on the voltage-ampere characteristic curve is dynamic resistance. The expression of nonlinear resistance characteristics is complicated, but these nonlinear relations are widely used in electronic circuits.2. Classified by Material1) Wirewound resistor is made of resistive wires, wound high resistance alloy wires on an insulating skeleton, and coated with a heat-resistant glaze insulating layer or insulating paint. The wire-wound resistor has a low-temperature coefficient, high resistance accuracy, good stability, sound heat resistance, and corrosion resistance. It is mainly used for precise and high power resistance. The shortcoming is that the high-frequency performance is poor and the time constant is large.  ApplicationsIt has high securityAccurate measurement and balance current control is required.2) The carbon composition resistor is made from the mixer of granulated or graphite, an insulation filter, and a resin binder. The actual resistance of the resistor is determined by the ratio of the insulation material. The shape of the insulating binder is in the shape of roads and there are two metal caps at both the end of the roads. At both ends of the resistor, it has two wire conductors for easy connectivity in the circuit design. There are different colors that are printed on the resistor to find the value of it and the road is covered with the plastic coat.   ApplicationsThe composition resistor is used in the high energy pulses.·It has a relatively small size.·High voltage power supplies·Welding·High power3) A carbon film resistor is plated with a carbon layer on the porcelain tube, and the crystalline carbon is deposited on the ceramic rod framework. Furthermore, the temperature coefficient is from -100 to -900 ppm/°C. The carbon film resistor has the advantages of low cost, stable performance, wide resistance range, low-temperature coefficient, and low voltage coefficient, and is the most widely used resistor.  ApplicationsThe carbon film resistors are available in High plus stability.4) A metal film resistor is coated with a layer of metal on the ceramic tube, and the alloy material is plated on the surface of the ceramic rod skeleton by vacuum evaporation.Metal film resistor is more accurate than carbon film resistor, other advantages such as good stability, small noise, low-temperature coefficient. It is widely used in instrumentation and communication equipment.5) Metal oxide film resistors are coated with tin oxide on the ceramic tube, and a layer of metal oxide is deposited on the insulating rod. Because its body is an oxide, so it has high temperature stability, heat shock resistance, sound load capacity. According to the purpose, it is divided into universal, precision, high frequency, high voltage, high resistance, and high power type, also it can forms resistors network.IV Special Resistors1) KNP-RF: it also called a fuse resistor, which functions like a resistor and a fuse in the normal condition. When the circuit fails to make the power exceed the rated power, it will be blown as if the fuse is blown and the connection circuit is disconnected. The general resistance of the fuse resistance is small (0.33Ω ~ 10KΩ), and the power is also small. The common types of fuse resistors are RF10 type, RF111-5 fuse resistor symbol type, RRD0910 type, RRD0911 type, etc.2) Sensitive resistor: a resistor whose resistance value is sensitive to certain physical quantities (such as temperature, humidity, light, voltage, mechanical force, gas concentration, etc.). When these quantities change, The resistance value of the sensitive resistors will change with the change of physical quantity, showing different resistance values. According to the sensitivity to different physical quantities, the sensitive resistor can be classified as heat-sensitive, humidity-sensitive, photosensitive, pressure-sensitive, force-sensitive, magnetic sensitive, and gas sensitive. Sensitive resistors are almost made of semiconductor materials, thus they are also known as semiconductor resistors.The resistance of the thermistor varies with the change of temperature, when the temperature rise, this resistor is a negative temperature coefficient (NTC) thermistor. In most cases, the NTC thermistor is widely used, according to its different use, it can be divided into common NTC thermistor, steady-voltage NTC thermistor, thermometric NTC thermistor, and so on. The resistance of the photosensitive resistor changes with the intensity of the incident light. When the incident light is enhanced, the resistance decreases and the resistance increases when the incident light weakens.V How to Select a Suitable Resistor1) There are many types of fixed resistors, what materials and structures should be selected, it is necessary to consider the specific requirements of the application circuit. In high-frequency circuits, non-wire-wound resistors with small distributed inductance and capacitance should be selected,  such as carbon film resistor, metal resistor, and metal oxide film resistor, thin-film resistor, thick film resistor, alloy resistor, corrosion-resistant film resistor, etc. In high gain and small-signal amplifying circuits, low noise resistors should be used, such as metal film resistors, carbon film resistors, and wire-wound resistors, rather than synthetic carbon film resistors and organic solid resistors with high noise.There are different types of the resistor which are in the following:Carbon compositionCarbon PileCarbon filmPrinted carbon resistorThick and thin filmMetal filmMetal oxide filmWire woundFoil resistorAmmeter shuntGrid resistorSpecial veritiesLed ArrangementThe resistance value of the selected resistor shall be close to a nominal value of the calculated value in the application circuit, and the standard series resistor shall be preferred. The tolerance of resistors used in general circuits is ±5%~±10%. Precision resistors should be used in precision instruments and special circuits, with precision within 1%, such as 0. 01%, 0.1% or 0. 5% tolerance. The rated power of the selected resistor should not be arbitrarily increased or reduced in order to meet the requirements of the power capacity of the resistor in the application circuits.If the circuit is required to be a power resistor, the rated power can be 2 times higher than that required by the practical application circuit.Selection of Fuse ResistorFuse resistor, a kind of resistor with a protective function. The dual performance should be considered and the parameters such as resistance and power should be selected according to the specific requirements of the circuits. It is not only to ensure that it can fuse quickly when it is overloaded but also to guarantee that it can work stably for a long time under normal conditions. In addition, if the resistance is too high or the power is too large, it can not play a protective role either.Three basic principles for the selection of resistors:Select high-level standard resistors manufactured by a production line certified by the certification administrations.Select resistors manufactured by manufacturers with advantages of function, quality, efficiency,  price, and service.Select the manufacturer who meets the above requirements.VI Things Needing AttentionThe resistors should be checked before use, checking their performance is to measure whether the actual resistance value is consistent with the nominal value and whether the error is within the allowable range. The method is to measure the resistance by the multimeter.Two points need to pay attention to when measuring.1)The range should be determined according to the measured resistance when the pointer is indicated in the middle of the scale, which is easy to observe.2)After determining the resistor range, having zero adjustments is that the two table pens are directly touching (short circuit), that is, the "zero adjustments" device is adjusted so that the pointer is accurately pointed to the "0" of the Ω scale, and then the resistance value is measured again. Also, be careful not to touch both ends of the resistor or the metal part of the pen, otherwise, the test error will be caused.If the resistance measured by the multimeter is close to the nominal value, the basic quality is good, and if the difference is big or the multimeter does not work at all, this resistor is bad.VII Resistor Detection1. Appearance CheckFor a fixed resistor, check the logo clear firstly: intact protective paint, no charring, no scars, no cracks, no corrosion, resistive body and pin connected closely. For potentiometers, the axis flexible, proper tight, the comfortable handle should be the key point. If there is a switch, checking the switch whether is working properly.2. Multimeter Detection① detection of fixed resistanceWhen measuring, the different resistances are measured by the proper electric gears of the multimeter. For the pointer type multimeter, because the indicator of electric gear is nonlinear, the larger the resistance value, the more dense the indicator number is, so the more accurate the reading is, the larger the angle of needle deviation should be, to make more accurate reading numbers. If the measured result exceeds the error range of the resistor, the resistance value is infinite, unstable, or zero, which indicates that the resistor has been broken.In the measuring process, the hands holding the resistor should not contact the two pins of the resistor, which will affect the accuracy of the measurement. In addition, the multimeter can not be used to detect the resistance during power on, because online detection shouldn’t be allowed.② Detection of fuse resistors and sensitive resistorsThe resistance range of fuse resistors is generally only a few to dozens of Ω. If the detecting resistance is infinite, it indicates that the fuse has been fused. The resistance can also be measured online, measuring the grounding voltage at both ends respectively, if one end is equal to the power supply voltage and another end voltage is 0V, indicating the fuse resistor has broken.There are many kinds of sensitive resistors, in this section, taking thermistors as an example. As above mentioned, it is divided into positive temperature coefficient(PTC) thermistors and negative temperature coefficient(NTC) thermistors. For the PTC thermistor, the resistance value is usually small at normal temperatures. In the measurement, when using the electric soldering iron with burning heat close to the resistor, the resistance value will be obviously increased, which indicates the resistor is normal, and if no change appears, indicating the component is damaged. The NTC thermistor is the opposite.Under the circumstance without light, the resistance value of light-sensitive resistors is large, on the contrary, the measuring resistance will be reduced obviously when there is light, if there is no change, the component is damaged.③ Detection of variable resistors and potentiometerFirstly, measuring whether the resistance values between the two fixed ends are normal, if the detecting values are infinite or zero, or is larger or small than the nominal values, exceeding the tolerances, which indicates the device is damaged. If the resistance value of the resistive body is normal, then a meter pen of the multimeter is connected with the sliding end of the potentiometer, the other pen is connected with any fixed end of the potentiometer (adjustable resistor), and the footstalk is slowly rotated to observe whether the meter needle is stably changed.when the resistance value is changed from zero to the nominal value (or vice versa) from one end to the other end, and there is no jump or jitter in the course of rotation, which indicating the potentiometer is normal, if any, it is indicated that the sliding point of resistance is in poor contact3. Measuring resistance with bridgeIf the accurate measurement of resistor resistance is required, it can be measured by a bridge (digital). The resistance can be read from the display by inserting the resistor into the measuring end of the bridge by selecting an appropriate range. For example, when a resistor is made from a wire or a fixed resistor is processed to obtain a more accurate resistance value, under this situation, the resistance of the self-made resistor must be measured by a bridge.Different applications, the purpose of applying varistor, different voltage/current stress acting on the varistor, so the requirements for the varistors are different, thus it is necessary to pay attention to detecting. According to the purpose of the application, the varistors can be divided into two categories: the protection varistor and the circuit function varistor.1) Distinguish between the power supply, signal lines, and data wire protection for varistors, because they should meet the requirements of different technical standards.2) According to the difference of the continuous working voltage applied on the varistors, the power lines can be divided into two types: AC or DC, in addition, the aging characteristics of varistors under these two voltage stresses are different.3) According to the abnormal overvoltage of varistors, it can be divided into three types: surge suppression type, high power type, and high energy type.Surge suppression type: it is used to suppress transient overvoltages caused by lightning and improper operation. Transient overvoltages are random, aperiodic, and the peak value of current voltages may be very large.High power type: it is used to absorb a continuous group of pulses occurring in a period, for example, a varistor connected to a switching power converter, where the impulse voltage period occurs, and the period is knowable, so the energy value can generally be calculated. From this, we can see the peak value of voltage is not large, but occurs frequently, thus its average power is quite large.High energy type: it is used to absorb magnetic energy in large inductance coils such as generator excitation coils, lifting electromagnet coils, etc. For such applying requirements, the main technical index is energy absorption capacity.The protection of varistor can be used repeatedly in most applications, but sometimes it can be made into a one-off protection device such as a current fuse. For example, a varistor with short-circuit contact connected to a load of some current transformers. VIII How to Recognize a Resistor1. Color bands resistorThe first and second bands with four color bands represent the first two digits of the resistance respectively; the third band represents the multiplier; the fourth band represents the tolerance.   ColorDigitMultiplierToleranceBlack0100 Brown11011Red21022Orange3103 Yellow4104 Green51050.5Blue61060.25Violet71071Grey8108 White9109 Gold 10-15Silver 10-210None  20(1) The key to fast recognition is to determine the resistance value within a certain magnitude according to the color of the third band, and then to recognize the resistance of first and second band, following this way, the number can be read out quickly.GoldunitsBlacktensBrownhundredsRedthousandsOrangeten thousandsYellowhundred thousandsGreenmillionsBlueten millions(2) Memorize the number of colors represented by the first and second rings, the following table is the number each color represents.On the order of magnitude, they can be divided into three grades: gold, black, brown is Ω; red, orange, yellow are KΩ; green, blue is MΩ.(3) When the second band is black, the third band is represented by an integer, and a special case at the time of reading needs to be noted, for example, the third band is red, the resistance value is a whole number kΩ.(4) Remember the errors represented by the fourth band color, that is, gold is 5%, silver is 10%, colorless is 20%.Examples(1) When the four-color bands are yellow, orange, red, and gold successively because the third ring is red, the resistance range is several kΩ, according to the representing number of yellow and orange is "4" and "3" respectively, the reading number is 4.3 kΩ, and the fourth band is gold, so the error is 5%.(2) When the four-color bands are brown, black, orange, and gold in turn, because the third band is orange and the second band is black, the resistance range should be tens of kΩ, the brown is representing “1”, so the reading number is 10 kΩ, the fourth band is gold, its error is 5%.2. Chip resistorsChip resistors have the advantages of small size, lightweight, high installation density, high seismic resistance, sound anti-interference ability, and good high-frequency characteristic. It is widely used in computers, mobile phones, electronic dictionaries, medical e-products, video cameras, VCD machines,s, etc.Chip components can be divided into three types according to their shape: rectangular, cylindrical, and special-shaped. There are resistors, capacitors, inductors, transistors, and small integrated circuits. The nominal method of the chip components is different from that of the common components. The following is mainly about the nominal method of chip resistors.The resistance value of a chip resistor is the same as that of a general resistor. There are three methods of nominal resistance, but it is not exactly the same as that of general resistors.1) Digital nominal method (usually for general rectangular chip resistors)This method is using a three-digit number on the resistance body to indicate its resistance. Its first digit and second digit are significant digits, and the third digit represents the numbers of "0" added after the significant number, and this digit place does not appear as a letter.Example: “472′” represents “4700Ω”, “151” represents “150”.If it is a decimal, use "R" to denote "decimal point" and take up an effective digit, and the remaining two digits are valid numbers.Example: “2R4” represents “2.4Ω”, “R15” represents “0.15Ω”.2) Colour bands nominal method (used in general cylindrical fixed resistors)The chip resistor, like general resistors, is usually indicated by four/five/six bands. The first band and second band are significant numbers and the third band is a multiplier.IX. Resistor FunctionSmall power resistors are usually made of carbon film packaged in plastic shells, while high power resistors are usually wire wound resistors, which are made by metal wires with high resistance wrapped on the porcelain core.If the resistance value of a resistor is close to 0Ω, the resistor has not any effect on the current. In parallel with this kind of resistors, the circuit will be short-circuited and the current is infinitely large. If resistance is very large or infinite, the circuit is in series with such a resistor can be regarded as an open circuit, that is, the current is 0A. The commonly used resistor in the industry is between two these extreme cases. In other words, it has a certain resistance and can pass through a certain current, but the current is not as large as in a short circuit. The resistor's current limiting effect is similar to that of a small diameter tube connected to two large-diameter tubes to limit water flow. It is defined as the resistance corresponding to that 1V voltage is added to the conductor to generate 1A current, in fact, the term "resistance" refers to a property, whereas in electronic products, it often refers to a component such as a resistor.FAQ1. How does a resistor work?A resistor is a little package of resistance: wire it into a circuit and you reduce the current by a precise amount. ... A resistor like this is described as wire-wound. The number of copper turns controls the resistance very precisely: the more copper turns, and the thinner the copper, the higher the resistance.2. What are the 4 types of resistors?Resistor types:Fixed resistors.Variable resistors.Thermistors.Varistors.Light dependent resistors.3. What is resistor and its unit?Resistor is an electrical component that reduces the electric current. The resistor's ability to reduce the current is called resistance and is measured in units of ohms (symbol: Ω). If we make an analogy to water flow through pipes, the resistor is a thin pipe that reduces the water flow.4. What is resistor in simple words?A resistor is a passive two-terminal electrical component that implements electrical resistance as a circuit element. In electronic circuits, resistors are used to reduce current flow, adjust signal levels, to divide voltages, bias active elements, and terminate transmission lines, among other uses.5. What is the main function of resistor?A resistor is a passive electrical component with the primary function to limit the flow of electric current.6.How do you identify a resistor?Some resistors have contact plates on the bottom. Read the 3 or 4 numbers on the resistor. The first 2 or 3 represent the significant digits and the last indicates the number of 0s that should follow. For example, a resistor reading 1252 indicates a rating of 12,500 ohms or 1.25 kilo-ohms.7. What is resistor formula?According to Ohm's law, the voltage drop, V, across a resistor when a current flows through it is calculated by using the equation V=IR, where I is current in amps (A) and R is the resistance in ohms (Ω). So the voltage drop across R1 is V1=IR1, across R2 is V2=IR2, and across R3 is V3=IR3.8. What is difference between resistor and resistance?Resistance is the property of a conductor, which determines the quantity of current that passes through it when a potential difference is applied across it. A resistor is a electrical componet with a predetermined electrical resistance, like 1 ohm, 10 ohms 100 ohms 10000 ohms etc.9. What are the 2 types of resistors?The resistors are mainly divided into two types, first Fixed Resistors and second, variable resistors. In Fixed resistors, the electrical resistance of the resistor the remains same while in variable resistor it does change with some physical variable.10. What are the five examples of fixed resistor?The different types of fixed resistors include:Wire wound resistor.Carbon composition resistor.Carbon film resistor.Metal film resistor.Metal oxide film resistor.Metal glaze resistor.Foil resistor.11. What can be used as a resistor?Explained another way: an electrical circuit that has a difference of 2 volts, with 1 Ampere of current flowing through it, has a resistance of 2 Ohms. All electrically conductive materials are somewhat resistive, too. Because of this, even a good electrical conductor, such as metal wire, can be used as a resistor.12. How do you use a resistor in a circuit?Dividing voltage: You can also use resistors to reduce voltage to a level that's appropriate for specific parts of your circuit. For example, suppose your circuit is powered by a 3 V battery but a part of your circuit needs 1.5 V. You could use two resistors of equal value to split this voltage in half, yielding 1.5 V.13. What happens if there is no resistor in a circuit?If there really were no resistance in the circuit, the electrons would go around the circuit, and arrive back at the beginning of the circuit with as much energy as the potential difference (the voltage). That final energy is usually what is dissipated as heat or other types of energy by the circuit.14. How do you connect a resistor?Resistors are said to be connected in “Series”, when they are daisy chained together in a single line. Since all the current flowing through the first resistor has no other way to go it must also pass through the second resistor and the third and so on.15. What is the use of resistor color code?Components and wires are coded with colors to identify their value and function. Resistor Color Coding uses colored bands to quickly identify a resistors resistive value and its percentage of tolerance with the physical size of the resistor indicating its wattage rating.You May Also LikeHow to Distinguish Resistor Color Codes? (Axial Resistors)