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Introduction In general, the radio is constructed by mechanical devices, electronic devices, magnets, etc. It receives the audio signals emitted by broadcasting stations through converting electric wave signals. After the invention of the vacuum tube, the circuit and receiving performance of the radio had undergone revolutionary progress and improvement, that is valve radio. Later, with the development of technology, radios with transistors as the core gradually became popular. It's what we know as a transistor radio. Radios are still widely used for many functions. Here two main radios will be described in detail below. Catalog Introduction Ⅰ Valve Tube Radio 1.1 Vacuum Tube Radio Classifications 1.2 Advantages and Disadvantages of Valve Radio 1.3 German Vintage Valve Radio Models for Sale Ⅱ Transistor Radio 2.1 Transistor Radio Overview 2.2 Transistor Radio Selection Matters 2.3 Transistor Radio Brands for Sale Ⅲ Radio Further Development Ⅳ FAQ Ⅰ Valve Tube Radio The valve radio, also known as the vacuum tube radio, was a product of the early 20th century, and immediately became the new favorite of that era with the launch of the broadcasting station. By the late 1920s, vacuum tube radio equipment replaced the primitive spark-gap systems on most merchant ships. This new equipment could send and receive signals virtually worldwide, by using high frequency or "short-wave" bands. Tube technology allowed radio signals to be tuned with much greater precision than spark-gap. The basic design for tube radio was perfected by the 1930s and continued in use on merchant vessels into the 1980s. 1.1 Vacuum Tube Radio Classifications 🔺AM (Amplitude Modulation) RadioIn the era when tube radios were popular, AM radios were the mainstream products. Amplitude modulation wave modulates the high-frequency carrier with audio signal. Its waveform is symmetrical, the amplitude is the same as that of the modulated signal, and then obtain the audio signal after high-frequency component is filtered out. In addition, the frequency of the carrier signal (the frequency of the broadcasting station) is the carrier frequency.AM radios can receive medium-wave and short-wave broadcasts, and some can receive long-wave broadcasts. Since the mid-band frequency interval has been unified to 9KHz, its highest audio frequency is only 4KHz. So the sound quality is affected because of large electromagnetic interference.There are two main types of AM radios: direct-amplifier type and external (self) differential type1) Direct-amp radio, also called high-amp radio, its typical circuit structure is as follows:High Amplifier—Detection—Low Amplifier—Power AmplifierA circuit that uses a grid detector circuit and high-frequency positive feedback is called a regenerative radio, which can obtain higher sensitivity and amplitude selectivity. A regenerative radio with high amplifier and short wave can receive AM telegraph signals. Most of the old Japanese-made radios have such circuits. Direct-amp radios are prone to self-excitation of high-frequency signals, high-end and low-end gains are uneven, and regenerative radios without high-amplification have poor selectivity. In addition, the reed speakers with poor sound quality are generally used, so they are gradually replaced by superheterodyne radios.Simple regenerative radios mostly use reed speakers, which have high impedance (about 10K) and high sensitivity. It can be directly used as the load of the power amplifier tube, but the frequency range is only 350~3000Hz, so the sound quality is poor. Later regenerative radios applied moving coil speakers, and the sound quality was better. However, because of low impedance, an output transformer is required, and its primary impedance must match the load impedance of the power amplifier tube. Moving coil speakers are divided into permanent magnets, constant magnets and excitation. Among them, excitation horns are used in AC electronic tube radios, and their excitation coils can also be used as filter chokes. 2) Heterodyne RadioThe heterodyne radio adopts a frequency conversion circuit. The signal generated by its high-frequency oscillation circuit and the input signal have a certain frequency difference. After the two are mixed, a fixed intermediate frequency signal (455~465KHz) is generated. Some people call the oscillation frequency higher than the signal frequency a heterodyne type, and vice versa.Heterodyne plus intermediate frequency amplifier circuit is called superheterodyne. This type of circuit requires a single electron tube to oscillate, and later a multi-pole or composite tube dedicated to frequency conversion appears. The superheterodyne type is the most common circuit of commercial radios. It has an automatic volume control circuit and can add tuning instructions. The circuit principle will be described in detail later. The superheterodyne radio can obtain more stable and higher gain due to amplifying the fixed frequency. The disadvantage is that there is image frequency interference.The circuit structure of a typical superheterodyne radio is as follows:Frequency Conversion—Middle Amplification—Detection—Low Amplification—Power Amplification 3) Autodyne Frequency Conversion RadioUsing ordinary pentodes for frequency conversion is only suitable for the mid-band, and the middle frequency is 175KHz. Due to the popularization of special frequency conversion tubes, it is rarely used now. Figure 1. Vintage AM Radio 🔺FM (Frequency Modulation) RadioFM radio is a radio that transmits radio signals through the use of FM frequency modulation carrier. Due to the shorter wavelength, the signal transmitted is much better than that of the radio that uses the AM wavelength. However, due to the short wave, the transmission distance is relatively short.FM wave is to use audio signal to modulate the frequency of high frequency carrier. Its advantages include strong anti-interference ability, high signal-to-noise ratio, good frequency bandwidth and sound quality, in addition, the audio frequency can reach 20Hz~15000Hz. Because the FM wave works in the ultra-high frequency band, it can accommodate many radio stations. With its linear propagation characteristics, the same frequency can be reused at a distance of hundreds of kilometers, which can effectively solve the problem of congestion of medium and short wave radio stations.Modern FM broadcasting is compatible with stereo and mono channels(in the early days of stereo broadcasting, two frequencies were used and two radios for reception). Some hobbyists are likely to use a simple super-regenerative circuit to receive FM broadcasts. Because it works in a self-oscillation state, the work is unstable and has strong super-noise. 1.2 Advantages and Disadvantages of Valve Radio Advantages of Valve Radio 1) The valve tube circuit has a simple structure and good anti-overload performance.2) The characteristics of the power amplifier circuit of the tube radio are better than those of the transistor or integrated circuit power amplifier. The screen current of the Class A power amplifier circuit with an output transformer for output impedance matching has little change at zero signal and full signal. So the performance is stable, the distortion of the line work area is very small, and the harmonic content is very rich .3) The speakers used in valve radios are generally larger in diameter than those of transistor or integrated circuit radios.4) The IF circuit characteristics of tube radios are better than those of transistor or integrated circuit radios.5) Have collection value. Disadvantages of Valve Radio As for the shortcomings, valve tubes that are large in size and used as basic components, built-in accessories are also bulky, power consumption has also increased, the overall quality has become poor, inconvenient to carry, and poor seismic performance. In addition, it is very difficult to make FM stereo radio devices, because early tube radios can only receive shortwave and medium waves. These shortcomings eventually led to the replacement of tube radios by transistor radios. Vintage Valve Radios - Will they work? 1.3 German Vintage Valve Radio Models for Sale AEG RadioBlaupunktGerman EMUDGraetz Vintage RadioGrundig Vintage RadioHornyphon Vintage RadioVintage Koerting RadioGerman Metz Vintage RadioVintage Nordmende RadioPhilips Vintage RadioVintage Saba RadioVintage Siemens RadioTelefunken Radio Figure 2. Vintage Valve Radio Ⅱ Transistor Radio 2.1 Transistor Radio Overview The transistor radio is the second generation radio after the valve radio. Compared with vacuum tubes, transistors are small in size, light in weight, resistant to vibration, long in life, and low in power consumption. This kind of radios can be made compact and have relatively stable performance. Therefore, after the advent of transistor radios, a large number of portable radios and pocket radios have emerged. They are very convenient for daily use. The Regency TR-1 was the first commercially manufactured transistor radio by developed by Texas Instruments and IDEA Inc., introduced in 1954.Transistor radios use transistors to process and amplify signals. Simple to use, it is a small transistor-based radio receiver. 2.2 Transistor Radio Selection Matters To choose a good transistor radio, you must first understand four basic relationships:1) The larger the chassis volume, the better the sound quality.2) The larger the horn diameter, the better the sound quality.3) The larger the battery volume, the longer the relative service life of the battery.4) The longer the magnetic bar, the higher the sensitivity.Secondly, we should also pay attention to five points when selecting:1) The change after the power supply voltage is reduced should be small. When selecting, you can have listening trial, because the impact on a high-quality radio should not be significant.2) The distortion of the offset radio should be small. After finding a radio station, having the left and right adjustments, the distortion should be small. In addition, there should be no whistling sound, otherwise, the frequency characteristics of the intermediate frequency part are poor.3) The volume change should be small when turning the button.4) Human body induction has little influence. When a person's body is close to the radio, it will have a certain impact on the work of the radio. This situation is particularly obvious for shortwave.5) The noise should be small. Noise generally includes electrical noise and mechanical noise. Turn the radio to a place where there is no station, and turn on the volume to the maximum. At this time, the minimum sound is better. Listen to a program to check whether there are noises caused by resonance of certain components when the volume is loud. Finally, you should also pay attention to whether the tuning knobs and buttons are coordinated and effective, and whether the shell of the radio is damaged or not. Vintage Transistor Radios Show And Tell 2.3 Transistor Radio Brands for Sale EdifierGAORUI HOME TEXTILESONYRoltonHALFSUNPandaSoaiyNintaus Figure 3. Regency tr-1 Transistor Radio Ⅲ Radio Further Development With the advent and development of integrated circuits, transistors have been replaced by integrated circuits, that is the third-generation radios invention, sometimes also known as semiconductor radios.After the radio uses integrated circuits, not only the size can be made smaller, but also the reliability is high. As the number of integrated circuit components is getting larger and larger, radios made with it have better performance and more functions. The integration of radios has become an inevitable trend.   Ⅳ FAQ 1. What is a vacuum tube radio?A vacuum tube, also called a valve in British English, is an electronic device used in many older model radios, television sets, and amplifiers to control electric current flow. The cathode is heated, as in a light bulb, so it will emit electrons. ... The anode is the part that accepts the emitted electrons. 2. Do valve radios still work?A valve radio will never be as reliable as a transistor set, and short of ripping out the chassis and replacing it with a transistor circuit, we aren't going to make it that reliable. However, some designs of valve set are more unreliable than others, and the main factor seems to be heat. 3. What did valves do in radios?The valve was useful as an electronic switch and its first use was in radio circuits detecting signals. The valve has two elements - a wire and a metal plate surrounded by a vacuum. The electricity flows between them. 4. How does a tube radio work?The basic working principle of a vacuum tube is a phenomenon called thermionic emission. It works like this: you heat up a metal, and the thermal energy knocks some electrons loose. 5. When did radios stop using vacuum tubes?1950s-60s - Most vacuum tubes were replaced by transistors in the west. 1970s-80s Tubes are still used in many specialized applications like broadcast television and radio. 6. Why did we stop using vacuum tubes?Vacuum tubes suffered a slow death during the 1950s and '60s thanks to the invention of the transistor—specifically, the ability to mass-produce transistors by chemically engraving, or etching, pieces of silicon. Transistors were smaller, cheaper, and longer lasting.A transistor is a semiconductor device used in electronic circuits as to function as "on" and "off" switching and amplifying device in the electronic circuits. ... Radio is a device which transmit and amplifies signals. The modern radio uses transistor since it is smaller in size. 7. Are transistor radios still being made?Transistor radio is an obsolete term now, carried over from when having transistors rather than tubes made small radios possible. It has come to be analogous to a portable, battery-powered radio, so while I will be making some recommendations, they likely will have integrated circuits, rather than transistors.It is a radio receiver which uses transistors to amplify the sound. Transistor radios can be cheap and small and some use very little electric power. Some can amplify the weak radio waves that are usually not picked up by weaker vacuum tube radios. 8. What does a transistor radio do?The function of transistors in radios is straightforward. Sounds are recorded through a microphone and turned into electrical signals. Those signals travel through a circuit, and the transistor amplifies the signal, which is subsequently much louder when it reaches a speaker. 9. Why was the transistor radio invented?One goal was to find a replacement for fragile and energy-wasting vacuum tubes. Building on war-time research, John Bardeen and Walter Brattain, working with group leader William Shockley, developed a device they called a transistor. 10. Where was the transistor radio invented?There was a tremendous push during the war to reduce the size and power consumption of vacuum tubes, particularly because the receivers used in radio-controlled bombs depended on vacuum tube technology. “Not long after the war ended, the transistor was developed at Bell Labs, in 1947. 11. What is the name of first transistor radio?Regency TR-1In July 1954 the Texas Instruments and Industrial Development Engineering Associates (I.D.E.A.) companies embarked on a six month project to produce a pocket-sized radio for the Christmas market. The result was the Regency TR-1, the world's first pocket transistor radio.

Ⅰ Introduction   A capacitor is an electrical device that stores energy as an electric field. It consists of two metal plates separated by a dielectric or non-conducting material. Fixed capacitance and variable capacitance are the two broad categories of capacitors. The most common are fixed capacitance capacitors, but variable capacitance capacitors are also available. Rotary or trimmer capacitors are examples of these. Fixed capacitance capacitors are classified as film capacitors, ceramic capacitors, electrolytic capacitors, and superconductor capacitors. Follow the link to learn more about the various types of capacitors. This article goes into greater detail about the ceramic capacitor.     Images of  Capacitors     Catalog Ⅰ Introduction Ⅱ Ceramic Capacitor Basics 2.1 What is a Ceramic Capacitor? 2.2 Ceramic Capacitor Polarity and Symbol 2.3 Types and Properties of Ceramic Capacitors 2.4 Ceramic Capacitor  Classes Ⅲ Why Ceramic Capacitors Mostly Used in Electronic Circuit than Others? 3.1 Applications and Uses of Ceramic Capacitor 3.2  Properties or Advantages of Ceramic Capacitors Ⅳ How to Read Ceramic Capacitor? 4.1 Where to Use a Ceramic Capacitor? 4.2 How We Read Ceramic Capacitor Value？ 4.3 Calculate Ceramic Capacitor Value 4.4 Some Examples Ⅴ FAQ     Ⅱ Ceramic Capacitor Basics   2.1 What is a Ceramic Capacitor?   The capacitor value is unchangeable.  The working ceramic material acts as the dielectric, and it is a ceramic capacitor constructed of two or more alternating layers of ceramic and it has a metal layer acting as the electrodes, and the composition of the ceramic material defines the electrical behavior and thus applications.   As per below video of ceramic capacitors:     What is CERAMIC Capacitor _ Uses _ complete information in English     2.2 Ceramic Capacitor Polarity and Symbol   Ceramic capacitors are the most common type of capacitor found in all electrical devices, and they use a ceramic material as the dielectric. Ceramic capacitors are non-polarity devices, which means they have no polarities. As a result, we can connect it to a circuit board in any direction.   As a result, they are far safer than electrolytic capacitors. The symbol for a non-polarised capacitor is shown below. Many capacitors, such as tantalum beads, do not have polarity.     Ceramic Capacitor Polarity and Symbol       2.3 Types and Properties of Ceramic Capacitors   Ceramic capacitors come in three varieties, though other styles are available:   Resin-coated leaded disc ceramic capacitors for through-hole mounting.Multi-Layer Ceramic Capacitors with Surface Mount (MLCC).Microwave bare lead-free disc ceramic capacitors that are designed to fit into a PCB slot.   different types of ceramic capacitors     Ceramic disc capacitors   Ceramic disc capacitors are made by coating a ceramic disc on both sides with silver contacts. These devices can be made from multiple layers to achieve higher capacitances. Ceramic disc capacitors are typically through-hole components that are dwindling in popularity due to their size. If capacitance values allow, MLCCs are used instead. Ceramic disc capacitors have capacitance values ranging from 10pF to 100F and voltage ratings ranging from 16 volts to 15 kV and higher.   Multi-layer ceramic capacitor (MLCC)   MLCCs are fabricated by precisely combining finely ground granules of paraelectric and ferroelectric materials and then layering the mixture with metal contacts. Following the completion of the layering, the device is heated to a high temperature and the mixture is sintered, resulting in a ceramic material with the desired properties. The resulting capacitor is essentially made up of many smaller capacitors connected in parallel to increase the capacitance. MLCCs have 500 layers or more, with a minimum layer thickness of about 0.5 microns. As technology advances, layer thickness decreases, and higher capacitances for the same volume are achieved.     2.4 Ceramic Capacitor  Classes   Different ceramic capacitor classes are defined based on the working temperature range, temperature drift, and tolerance:   Class 1 Ceramic Capacitors   These are the most temperature-stable capacitors. They have nearly linear properties.The most commonly used dielectric compounds are.Magnesium Titanate is used to achieve a positive temperature coefficient.Calcium Titanate is used in capacitors that have a negative temperature coefficient.   Class 2 Ceramic Capacitors   Class 2 capacitors perform better at the price of volumetric efficiency, but at the expense of lower accuracy and stability. As a result, they are typically used for decoupling, coupling, and bypass applications where precision is not critical.Temperature range: -50 to +85 degrees CelsiusThe dissipation factor is 2.5 percent.Accuracy ranges from average to poor.   Class 3 Ceramic Capacitors   Class 3 ceramic capacitors have a high volumetric efficiency but a low dissipation factor. It is unable to withstand high voltages. Barium Titanate is a common dielectric.Temperature range of +10C to +55C will cause a -22% to +50% change in capacitance for a Class 3 capacitor.Dissipation factor: 3 to 5%.It will have a low level of accuracy (typically 20% or -20/+80%).   Class 3 is typically used for decoupling or in other power supply applications where accuracy is not critical.     Ⅲ Why Ceramic Capacitors Mostly Used in Electronic Circuit than Others?   Many circuits, particularly electronic circuits, use ceramic capacitors, as you may have noticed. Ceramic capacitors are largely used over electrolytic or other capacitors.   Ceramic capacitors     3.1 Applications and Uses of Ceramic Capacitor   In electronic sensor circuits, ceramic capacitors are used.Ceramic capacitors are used in the transmission and reception of electronic signals.Ceramic capacitors are applied in circuits such as audio mixers, controllers, and equalizers.Ceramic capacitors are suitable for frequency-dependent circuits, such as electronic filter circuits, audio circuits, radio signal transmitters, and receiver circuits. Resonant circuits, like radio frequency communication system, needs ceramic capacitors, too.Ceramic capacitors are used in alternating current circuits for no polarity such as high voltage protection circuits, power circuit breakers, and so on.Ceramic capacitors are used in direct current motors to reduce radio frequency noise.Ceramic capacitors can also be used as Bypass Capacitors.Why Ceramic Capacitors mostly used in Electronic Circuit?     3.2  Properties or Advantages of Ceramic Capacitors   Ceramic capacitors are available in extremely small sizes, which is a significant benefit. Because of the numerous electronic circuits, in fact, most modern electronic circuits necessitate the use of small size capacitors.   Many critical electronic circuits necessitate the use of very small capacitors. Ceramic capacitors are available in a wide range of sizes.   Ceramic capacitors can provide very high stability; in fact, they offer a wide range of stability.   Ceramic capacitors have a low temperature coefficient and a higher voltage breakdown characteristic.        5. Ceramic capacitors are the best choice for high-frequency applications.     Ⅳ How to Read Ceramic Capacitor?   Two reference tables   MarkingCapacitance (pF)Capacitance (ìF)101100 pF0.0001 ìF221220 pF0.00022 ìF471470 pF0.00047 ìF1021,000 pF0.001 ìF2222,200 pF0.0022 ìF4724,700 pF0.0047 ìF10310,000 pF0.01 ìF22322,000 pF0.022 ìF47347,000 pF0.047 ìF104100,000 pF0.1 ìF224220,000 pF0.22 ìF474470,000 pF0.47 ìF1051,000,000 pF1 ìF2252,200,000 pF2.2 ìF4754,700,000 pF4.7 ìF     Letter printed capacitor indicate tolerance LetterToleranceA±0.05 pFB±0.1 pFC±0.25 pFD±0.5 pFE±0.5%F±1%G±2%H±3%J±5 %K±10%L±15%M±20%N±30%P–0%, + 100%S–20%, + 50%W–0%, + 200%X–20%, + 40%Z–20%, + 80%     4.1 Where to Use a Ceramic Capacitor?   Ceramic capacitors are applied in a variety of applications. It is primarily used for filtration. It is used in a signal or frequency circuit to filter and purify the signal. It can convert a direct current to a direct current. The ceramic capacitor is a genre of energy storage device. It stores the DC while passing the AC. This is what the ceramic capacitor looks like.     4.2 How We Read Ceramic Capacitor Value？     alphabetic code     The first is an alphabetic code that indicates the component's tolerance. The second is a numeric code that tells us the actual capacitance of the capacitor.   So let's take a look at our example right now. In our example, the value is 102 k. The first significant digit in the code is one, and the second significant digit is zero. As a result, these are the numbers in front of our multiplier.         How to read the values of Ceramic Capacitors?   4.3 Calculate Ceramic Capacitor Value   So, if we take your multiplier, which is two, and looks at the chart, that equals two zeros. As a result, we append two zeros to the end of the number. So, picofarad, it's 1000. Now, K represents our component tolerance, which in this case is plus or minus 10%. So that's how we figure out the capacitor's size and rating.   Now I'm going to show you how to use a multimeter to measure the capacitance of a capacitor. In this example, I'm using a capacitor with the numerical value 103 written on it, which equals 10-nanofarads.       nine ferrites   When you look at the display of what is rated, you'll notice that its practical rating is it works, and it has nine ferrites. So tolerances are around 10%. When you connect it to your actual multimeter, In this one, make sure you have an appropriate terminal. As you can see, I have the capacitance symbol in the bottom right-hand corner. Then, make sure your multimeter is set to the appropriate range. Then double-check that you've selected the correct option.   Ceramic disk capacitor codes table   Picofarad pFNanofarad nFMicrofarad FCode100.010.00001100150.0150.000015150220.0220.000022220330.0330.000033330470.0470.0000474701000.10.00011011200.120.000121211300.130.000131311500.150.000151511800.180.000181812200.220.000222213300.330.000333314700.470.000474715600.560.000565616800.680.000686817500.750.000757518200.820.00082821100010.00110215001.50.0015152200020.00220222002.20.002222233003.30.003333247004.70.0047472500050.00550256005.60.005656210000100.110215000150.01515222000220.02222333000330.03333347000470.04747368000680.0686831000001000.11041500001500.151542000002000.22542200002200.222243300003300.333344700004700.474746800006800.68684100000010001105150000015001.5154200000020002205220000022002.2225330000033003.3335470000047004.7475   The final number written on a ceramic capacitor is the power of ten multiplied by the first two numbers. If a ceramic capacitor has the code 682, First, look at the last number. So, as we can see, the final number is 2. The multiplier is now 102.   4.4 Some Examples   204 = 20×104 = 200000 PF 472 = 47×102 = 4700 PF 502 = 50×102 = 5000 PF 330 = 33×100 = 33 PF   [100 = 1] UNITS   1000 nanofarad(nF) = 1 microfarad(µF) 1 picofarad = 10-12farads. Nano= 10-9 Micro= 10-6 1 Nano Farad= 10-9 Farad 1 Microfarad (µF)= 10-6 Farad 1 nF = 1000 pF 1 pF = 0.001 nF   Example:   convert 15 nF to pF: 15 nF = 15 × 1000 pF = 15000 pF   Capacitor voltage code   0G4VDC0L5.5VDC0J6.3VDC1A10VDC1C16VDC1E25VDC1H50VDC1J63VDC1K80VDC2A100VDC2Q110VDC2B125VDC2C160VDC2Z180VDC2D200VDC2P220VDC2E250VDC2F315VDC2V350VDC2G400VDC2W450VDC2H500VDC2J630VDC3A1000VDC   Ⅴ FAQ   1. What is ceramic capacitor used for? Ceramic capacitors are used for all types of circuits in a number of applications. There are four main capacitor applications that are described in detail below: coupling, decoupling, smoothing, and filtering.   2. Do ceramic capacitors go bad? Like mica capacitors, ceramic capacitors also very rarely go bad. Do not replace ceramic disc capacitors unless you are sure one has gone bad. ... While replacing the capacitors, check the radio's resistors. Since you will be replacing the capacitors, you should snip one lead of each paper and electrolytic capacitor.   3. Why do ceramic capacitors fail? Ceramic capacitors can fail in a couple of ways. They can be mechanically damaged - too much physical stress (pressure on the part or the board is bent a little too much) can cause a crack. The capacitor will then develop short circuits between layers. It acts more like a resistor in that case.  4. When should you use a capacitor? Capacitors are widely used in electronic circuits for blocking direct current while allowing alternating current to pass. In analog filter networks, they smooth the output of power supplies. 5. What is the practical use of capacitor? The most common use for capacitors is energy storage. Additional uses include power conditioning, signal coupling or decoupling, electronic noise filtering, and remote sensing. Because of its varied applications, capacitors are used in a wide range of industries and have become a vital part of everyday life.  6. Why capacitor is not used as battery? Capacitors don't provide large amount of energy because they have less energy density than batteries. Capacitors are useful to provide short duration power requirements because they can be charged or discharged at a higher rate than the batteries. 

Introduction Linear Displacement Sensor, also called Linear Transducer or Linear Potentiometer Sensor, is a device used to monitor and measure linear position, which convert mechanical physical quantities into electrical signals. Linear potentiometer is a type of variable resistance sensor, designed to measure the displacement of a slider or wiper in a linear direction. Also known as a slider or pot, linear potentiometers produce a changing rate of resistance, dependent on the position of a slider or wiper. LVIT Linear Position Sensor Technology Catalog Introduction Ⅰ Linear Displacement Sensor Working Principle Ⅱ Linear Potentiometer Sensor Design Parameters Ⅲ Linear Transducer Applications Ⅳ Linear Displacement Sensor Types Recommendation Ⅴ Linear Potentiometer Sensor Installation Ⅵ Linear Transducer Operating Requirements Ⅶ Linear Displacement Sensor Use Matters Ⅷ FAQ Ⅰ Linear Displacement Sensor Working Principle The function of the linear displacement sensor is to convert the linear mechanical displacement into an electrical signal. In order to achieve this effect, the sensor slide rail is connected to a steady-state DC voltage, allowing a small current of microamperes to flow, and the voltage between the slide and the starting end is proportional to the length of the slide. Using the sensor as a voltage divider can minimize the requirements for the accuracy of the total resistance of the sliding rail, because the resistance change caused by the temperature change will not affect the measurement result. The linear displacement sensor is actually a sliding rheostat. Using the sensor as a voltage divider can minimize the requirements for the accuracy of the total resistance of the sliding rail, because the resistance change caused by the temperature change will not affect the measurement result. Figure 1. KTC 300mm Linear Displacement Sensor Ⅱ Linear Potentiometer Sensor Design Parameters For the general linear displacement sensor:Wear resistance life: >100X106 timesLinear accuracy error: <0.05%Repeatability error: <0.005mmMaximum moving speed: 10m/sImpact factor: IEC 68-2-29:1968 50gVibration factor: IEC 68-2-6:1982 20gMaximum allowable voltage: DC60V/5KΩ～20KΩ; DC36V/2KΩ～4KΩ; DC24V/1KΩTemperature drift coefficient: <1.5ppm/℃ Figure 2. KTR-75mm Linear Displacement Transducer Ⅲ Linear Transducer Applications 1) KTC, KTM, LS tie rod structure is a general structure, with optional pull ball universal head or universal head, can reduce the adverse effects caused by the installation of non-neutral. They are suitable for injection molding machines, textile machinery, woodworking machinery, etc.2) KPC and KPM fixed belts at both ends are hinged and sporty, suitable for swinging, and in measurement systems where the sensor body cannot be fixed, and the sensor will move with the measurement movement.3) KTF and KFM slider types are suitable for the application of the smallest installation length size. With the extension arm, it can eliminate the adverse effects of installation misalignment.4) KTR type is a miniature self-recovery rod structure, no need to tow and install.5) KPF type can also detect the internal displacement of the cavity. Figure 3. KPM Linear Displacement Sensor Ⅳ Linear Displacement Sensor Types Recommendation 🔺Tie Rod TypeUniversal drawbar conductive plastic film series, effective stroke 75mm ~ 1250mm, 4mm buffer stroke at both ends, precision 0.05%~ 0.04%FS. The surface of the shell is anodized, anti-corrosion.Built-in conductive plastic measuring unit, no temperature drift, long life, and automatic electrical grounding function. The sealing grade is IP67, DIN430650 standard plug and socket, which can be applied to most general occasions.The tie rod ball joint has 0.5mm automatic centering function, and the allowable extreme movement speed is 10m/s.🔺Sliding TypeGeneral-purpose slider conductive plastic film series, effective stroke 75mm～3000mm, 4mm buffer stroke at both ends, precision 0.05%～0.02%FS. The surface of the shell is anodized, anti-corrosion.Built-in conductive plastic measuring unit, no temperature drift, long life, and automatic electrical grounding function. The sealing level is IP54 (IP57 when installed downwards), DIN430650 standard plug and socket, which can be used in most general occasions, especially the length direction is limited, the alignment is difficult.The tie rod with the ball head has 10mm automatic correction function, and the allowable limit motion speed is 10m/s. Figure 4. KPC Linear Displacement Sensor Ⅴ Linear Potentiometer Sensor Installation 1) The installation of the linear displacement sensor should balance two ends. Do not tighten the fixing bracket screws before the limit position is determined. The linear displacement sensor fixing bracket screws can be locked after adjusting the stroke.2) The pull-ball universal head of the tie-rod displacement sensor allows a centering deviation with a radius of 1mm. Of course, the shorter the specification, the smaller the centering deviation is recommended.3) After fixing the linear displacement sensor, when retracting the tie rod, the cylindrical body of the universal ball head should be able to have gaps in the four radial directions. Or adjust the mounting position of the universal head or the mounting bracket position near the extended end.4) If there is a big misalignment when the pull rod is pulled out, adjust the mounting bracket near the end of the plug. This can be used as an auxiliary review method.5) The mounting rod of the pull ball universal head and the pull rod are allowed to tilt at an angle of 12°. However, if the centering deviation and tilt deviation are both large during installation, the stability and service life of the electronic ruler will be affected. So further adjustment is required.6) The slider electronic ruler can reduce the workload of adjusting the neutrality, but the auxiliary extension rod cannot be cancelled. Because the stability and service life due to the poor neutralization will occur, and even damage the sensor.7) After all adjustments are made, tighten the mounting screws to make the grounding resistance less than 1. Measure the resistance between the cover screw of the potentiometer sensor and the mounting bracket with a multimeter in the 200 block.8) When using a four-wire system or wiring with a shielded wire, the grounding end of the linear potentiometer should be connected, and the fourth end or shielding wire should be grounded at the end of the electric control box correctly. Figure 5. KTM Linear Displacement Sensor Ⅵ Linear Transducer Operating Requirements 🔺The supply voltage should be stable.Industrial power supply requires ±0.1% stability. For example, the reference voltage is 10V, and the fluctuation of ±0.01V is allowed under the fluctuating voltage. Otherwise, it will cause the displayed trap to fluctuate. 🔺Prevent electrostatic interference.Electrostatic interference and FM interference can easily make the digital display of the linear displacement sensor jump. Separate the strong current line of the equipment from the signal line of sensor in a wire duct. The potentiometer should use a grounding support, and its shell (the resistance between the end cover screw and the support should be less than 1Ω) must be well grounded. The signal line should be shielded and well grounded where at one end of the electrical box.In the case of electrostatic interference, the voltage measurement of the general multimeter is normal, but it shows the digital beating, even the phenomenon is the same when the high-frequency device is interfered. To verify whether it is electrostatic interference, use a power cord to short-circuit the cover screw of the sensor with a certain point of metal on the machine. However, it is difficult to eliminate high-frequency interference by the above-mentioned methods, which occurs frequently in robots and inverters. Stopping the robot or the inverter power saver can test it. 🔺WiringLines "1" and "3" are power lines, and "2" is the output line. Once the above line is connected wrongly, there will be large linear errors, resulting in poor control accuracy, and display bounce easily. 🔺The power supply capacity should be sufficient.If the power supply capacity is too small, the following situations are likely to occur: the mold clamping movement will cause the display of the glue injection ruler to jump, or the melt movement will cause the display of the mold clamping potentiometer sensor to fluctuate. Especially when the power supply of solenoid valve drive power supply is combined with the sensor, the above-mentioned situation is prone to occur. In severe cases, the voltage fluctuation can be measured with the voltage file of a multimeter. If the problem cannot be solved, even if the electrostatic interference and high-frequency interference are eliminated, the neutrality is also bad. At this time, you can check the power supply efficiency. 🔺Installation angleThe angle tolerance is ±12°, and the parallelism tolerance is ±0.5mm. If both are too large, it will cause the display number to jump. In this case, the angle and parallelism must be adjusted. 🔺Prevent short circuit.During the working process of the displacement sensor, the data is regularly displayed at a certain point or no data. In this case, it is necessary to check whether the connection line insulation is damaged and the ground short circuit caused by regular contact with the machine's metal casing. 🔺Avoid aging.For the linear displacement sensor that has been used for a long time, the seal is aging, there may be a lot of impurities, such as oil and water mixture, which affect the contact resistance of the brush, and cause the display number. It can be considered as the early damage of sensor. Figure 6. KTF Linear Displacement Sensor Ⅶ Linear Displacement Sensor Use Matters 1) If the potentiometer sensor has been used for a long time, and the seal has been aging, there are a lot of impurities mixed in, and the water mixture and oil will seriously affect the contact resistance of the brush, which will cause the displayed number to jump continuously. At this time, it can be said that the electronic ruler of the linear displacement sensor has been damaged and needs to be replaced.2) If the capacity of the power supply is small, there will be many situations. Therefore, the power supply should have sufficient capacity. Because insufficient capacity will cause the following situation: The movement of the melt will change the display of the sensor to cause the fluctuations,  resulting in a large error in the measurement result.If the driving power of the solenoid valve and the power supply of the linear displacement sensor are at the same time, the above situation is more likely to occur. In serious cases, the voltage range of the multimeter can even measure the relevant fluctuations of the voltage. If the situation is not caused by high-frequency interference, electrostatic interference, or insufficient neutrality, then it may be caused by the small power supply.3) FM interference and electrostatic interference may cause the digital scale of the linear displacement sensor to jump. The signal line of the sensor and the strong current line of the equipment should be separated from the wire duct. Use the grounding support to have good contact with the ground. The signal wire needs to use a shielded wire, and a section of the electrical box should be grounded to the shielded wire.If there is high-frequency interference, the voltage measurement with a multimeter will usually display abnormally. When there is electrostatic interference, the situation is the same as that of high-frequency interference. To prove whether it is electrostatic interference, you can use a power cord to short-circuit the cover screw of the sensor with some metal on the machine. As long as it is short-circuited, the e-interference will be eliminated immediately. However, if you want to eliminate high-frequency interference, it is difficult to use the above method. Frequency-conversion power savers and robots often have high-frequency interference, so you can try to stop them to verify the interference.4) The power supply voltage must be stable. The industrial voltage needs to meet the stability of ±0.1%. For example, if the reference voltage is 10V, a fluctuation of ±0.01V can be allowed. If it is not, it will cause a display fluctuation. But if the amplitude of the display fluctuation at this time does not exceed the amplitude of the fluctuation voltage, then the potentiometer sensor is normal.5) As for the linear displacement sensor installation, the parallelism can be allowed to have an error of ±0.5mm, and the angle can be allowed to have an error of ±12°. However, if both are too large, then the display number will be bounced. So the parallelism and angle must be adjusted.6) During the connection process, be sure to pay more attention, the wires of the potentiometer sensor cannot be connected wrongly.   Ⅷ FAQ 1. What is a linear displacement sensor?A linear displacement sensor is a device used to monitor and measure linear position. They can also be called Linear Position Sensors or Linear Transducers. They are available in different sizes to measure different stroke lengths.   2. How does a linear displacement sensor work?Linear displacement transducers are linear sensors that work on the magnetostrictive principle, whereby a torsional strain pulse is induced in a specially designed magnetostrictive waveguide by the momentary interaction of two magnetic fields.   3. What is the linear displacement?Therefore; “Linear Displacement” can be defined as the movement of an object in a linear fashion along a single axis in a straight line, for example; from side to side or up and down. ... Linear Displacement is usually measured in millimetres or inches and has a positive and negative direction.   4. What are linear sensor potentiometers?A linear potentiometer is a type of position sensor. They are used to measure displacement along a single axis, either up and down or left and right. Linear potentiometers are often rod actuated and connected to an internal slider or wiper carrier.   5. What is the difference between linear potentiometer and rotary potentiometer?This potentiometer is similar in function to the rotary potentiometer. The only difference between these two, as the name suggests, is the linear motion of the knob, instead of rotary, for adjusting the resistance.   6. How does a potentiometer sensor work?Potentiometers work by varying the position of a sliding contact across a uniform resistance. ... A potentiometer has the two terminals of the input source fixed to the end of the resistor. To adjust the output voltage the sliding contact gets moved along the resistor on the output side.   7. What does a potentiometer sensor measure?A potentiometer sensor measures the distance or displacement of an object in a linear or rotary motion and converts it into an electrical signal.   8. How does a potentiometer measure displacement?To measure the displacement of the body, this body, which is moving, is connected to the sliding element of the potentiometer. As the body moves, the position of the slider located on the potentiometer also changes so the resistance between the fixed point and the slider changes.

ⅠIntroduction Channel MOSFETs are a type of Metal Oxide Semiconductor Device. It consists of the n-substrate in the center with a high concentration of light doping. This is a list of the three-terminal devices. It has unipolar characteristics because the majority of the charge carriers are essential for its operation. Because of the two p materials used in the circuitry, the majority of the carriers are holes. It is further subdivided based on the presence of channels.   Catalog ⅠIntroduction Ⅱ What is P-Channel  MOSFET? Ⅲ P Channel MOSFET Characteristics Ⅳ How P-Channel MOSFETs Are Constructed Internally? Ⅴ Types of P-Channel MOSFET 5.1 P Channel with Enhancement MOSFET 5.1.1  How a P-Channel Enhancement-type MOSFET Works? 5.1.2 How to Turn on a P-Channel Enhancement Type MOSFET? 5.1.3 How to Turn Off a P-Channel Enhancement Type MOSFET? 5.2 P Channel Depletion MOSFET 5.2.1 How a P-Channel Depletion-type MOSFET Works? 5.2.2 How to Turn on a P-Channel Depletion Type MOSFET? 5.2.3 How to Turn Off a P-Channel Depletion Type MOSFET? Ⅵ How to use only positive voltage in this p-channel MOSFET tutorial? 6.1 VGS Threshold 6.2 P-Channel MOSFET Tutorial and Explanation Ⅶ FAQ     Ⅱ What is P-Channel  MOSFET?   A MOSFET is formed when a lightly doped N-type substrate is connected to two highly doped P-type materials. Doping refers to the concentration of impurities added to the atom. The p-channel formed between the two P-type substrates could be the consequence of induced voltages or it could have existed previously.    MOSFET Symbol    Ⅲ P Channel MOSFET Characteristics   The voltage controlled devices are represented by MOSFETs.These devices have high input impedance values.The conductivity of the channel in a P-channel is caused by the application of negative polarity at the gate terminal.     Ⅳ How P-Channel MOSFETs Are Constructed Internally?    P-Channel MOSFET   A P-Channel MOSFET is consists of a P channel, which is a channel that is mostly made up of hole current carriers. N-type material is used for the gate terminals.  How the transistor operates and whether it turns on or off  is determined by the amount and type of voltage (negative or positive)     P-Channel MOSFET as a Switch. Turn ON a 12V Motor with Arduino. (Step-By-Step Guide)     Ⅴ Types of P-Channel MOSFET   The p-channel MOSFET’s are classified as:   (1)P-channel with the Enhancement MOSFET (2) P-channel with the Depletion MOSFET     5.1 P Channel with Enhancement MOSFET   This MOSFET is constructed with a lightly doped n-substrate. The length separates the two heavily doped p-type materials (L). This L is referred to as the channel length.   Above the substrate, a thin layer of type silicon dioxide is deposited. This layer is commonly referred to as the dielectric layer. The source and drain are formed by the two P types. The gate terminal is formed by the aluminum plating used above the dielectric. The ground is connected to the source and the body of the MOSFET.   The gate terminal has been subjected to a negative voltage. Because of the effect of capacitance, the positive concentration of charges settles below at the dielectric layer. Because of repulsive forces, the electrons present at the n substrate are shifted, and the uncovered value of the positive ions layer can be found there. In an n-type substrate, the holes, which are minority carriers, combine with a few electrons to form a bond.   However, further application of the negative voltage cracks the covalent bonds, thereby breaking the pairs formed between electrons and holes. It results in the formation of holes and an increase in the carrier concentration of holes in the channel. When a negative voltage is applied to the drain terminal, the channel becomes conductive, allowing current to flow through the transistor.     5.1.1  How a P-Channel Enhancement-type MOSFET Works? circuit example     5.1.2 How to Turn on a P-Channel Enhancement Type MOSFET?     To turn on a P-Channel Enhancement-type MOSFET, apply a positive voltage VS to the MOSFET's source and a negative voltage to the MOSFET's gate terminal (the gate must be sufficiently more negative than the threshold voltage across the drain-source region) (VGDS). A current will be allowed to flow through the source-drain channel as a result of this.   With a sufficient positive voltage, VS, applied to the source and load, and a sufficient negative voltage applied to the gate, the P-Channel Enhancement-type MOSFET is fully functional and operating in the active 'ON' mode.     5.1.3 How to Turn Off a P-Channel Enhancement Type MOSFET?   There are two ways to turn off a P-channel enhancement type MOSFET. You can either disconnect the bias positive voltage, VS, which powers the source. Alternatively, you can disable the negative voltage applied to the transistor's gate.     5.2 P Channel Depletion MOSFET When compared to n channel depletion MOSFETs, the formation of p channel depletion is simply in reverse. Because of the presence of p-type impurities in the channel, it is pre-built. When a negative voltage is applied to the terminal gate, the free holes that represent the minority carriers at the n-type are attracted to the channel of the positive type impurity ions. When a drain terminal is reverse biased in this condition, the device begins to conduct, but as the negative voltage in the drain terminal increases, the depletion layer forms.   This region is affected by the concentration of the layer formed by positive ions. The width of the depletion region influences the conductivity of the channel. The current at the terminal is controlled by varying the voltage value of the region. Finally, the gate and drain retain their negative polarity, while the source maintains its zero value.     5.2.1 How a P-Channel Depletion-type MOSFET Works?   circuit  P-Channel Depletion-type MOSFET   5.2.2 How to Turn on a P-Channel Depletion Type MOSFET? The gate voltage feeding the gate terminal should be 0V for maximum operation if you switch on a P-Channel Depletion-Type MOSFET. The drain current is at its maximum when the gate voltage is 0V, and the transistor is in the active 'ON' region of conduction.     5.2.3 How to Turn Off a P-Channel Depletion Type MOSFET?   There are two methods for turning off a P-channel MOSFET. You can either switch off the bias positive voltage, VDD, which powers the drain, or you can turn it back on. Alternatively, you can apply a negative voltage to the gate. The current is cut down when a negative voltage is used to the gate. As the gate voltage, VG, becomes more negative, the current decreases until it reaches cutoff, at which point the MOSFET is in the 'OFF' state. It prevents a great source-drain current from flowing.   MOSFET transistors are applied for switching as well as amplifying. MOSFETs are among the most widely used transistors today. Because of their high input impedance, they draw very little input current, which is simple to manufacture, can be made very small, and consume very little power.       Ⅵ How to use only positive voltage in this p-channel MOSFET tutorial?   6.1 VGS Threshold   VGSth: an abbreviation for Voltage Threshold from Gate to Source is one of their critical properties we need to know about using MOSFETs. The resistance between the DRAIN and SOURCE pins changes as the voltage difference between those two pins changes. This is the threshold at which a MOSFET turns on and off.   The resistance changes depending on whether the MOSFET is N-Channel or P-Channel.     6.2 P-Channel MOSFET Tutorial and Explanation   For a P-Channel MOSFET, look at the VGSth. VGSth is a negative value, as you may have noticed. As an example, consider the datasheet for an IRF5305.     specification   The specification of VGSth is -2.0V to -4.0V. So, how could this MOSFET work with an Arduino, LaunchPad, Raspberry Pi, or any other microcontroller? Is it really necessary to generate negative voltages?     It’s about the difference:   This is where the "negative voltage" myth comes into play: Because the datasheet says negative, you need negative voltage to work. Datasheets, on the other hand, never lie (except when they do...).   Let's take a literal look at what the specification says. "A negative four-volt voltage from gate to source." You could read it as "GATE voltage value minus SOURCE voltage value" in other words.   Consider the following voltages in this "high-side switch" configuration:     negative voltage     The GATE now has a voltage of 5 volts. The SOURCE is 5 volts as well. It means that the Vgs is 5V – 5V = 0V. In this case, the Vgs is 0 volts. This voltage indicates that the MOSFET is off, or that it is open.   This is the same circuit as before, but the GATE is now connected to ground rather than 5 volts.       circuit  example in 5 volts     Let's take another look at the SOURCE and GATE. The SOURCE remains at 5 volts. However, the GATE is now at the ground, indicating that it is 0V. If you subtract the GATE voltage from the SOURCE voltage, you get 0V – 5V = -5V. This will activate the MOSFET.   Have you noticed what just happened? Using only positive voltage supplies, we obtained a "negative" voltage...     Why use N-Channel over P-Channel?   A tutorial on when to use an n-channel and p-channel MOSFET would be required. A great application for P-Channel is in a circuit where the voltage levels of your load and logic are the same. For example, suppose you're attempting to activate a 5-volt relay with an Arduino. The current required by the relay coil is too high for an I/O pin, but the coil requires 5V to function. Use a P-Channel MOSFET to turn on the relay from the Arduino's I/O pin in this case.   If your load voltage is higher, such as 12 or 24V, you should consider using an N-Channel MOSFET in a "low side" configuration.   Ⅶ FAQ   1. How do you test P MOSFET? Hold the MosFet by the case or the tab but don't touch the metal parts of the test probes with any of the other MosFet's terminals until needed. 2) First, touch the meter positive lead onto the MosFet's 'Gate'. 3) Now move the positive probe to the 'Drain'. You should get a 'low' reading.   2. When would you use a MOSFET? Power MOSFETs are commonly used in automotive electronics, particularly as switching devices in electronic control units, and as power converters in modern electric vehicles. The insulated-gate bipolar transistor (IGBT), a hybrid MOS-bipolar transistor, is also used for a wide variety of applications.   3. What is MOSFET? MOSFET stands for metal-oxide-semiconductor field-effect transistor. It is a field-effect transistor with a MOS structure. Typically, the MOSFET is a three-terminal device with gate (G), drain (D) and source (S) terminals.   4. What are the types of MOSFET? Different Types of MOSFET Transistors PMOS Logic. As previously mentioned, the integration of a MOSFET allows for high levels of circuit efficiency when compared with BJTs. ... NMOS Logic. ... CMOS Logic. ... Depletion Mode MOSFET Devices. ... MISFETs. ... Floating-Gate MOSFETs (FGMOS) ... Power MOSFETs. ... DMOS.                  

2026 Executive Summary: Reading SMD Resistor CodesHow do you read SMD resistor codes? For standard 3-digit codes, the first two numbers are significant digits, and the third is the multiplier (10^x). For 4-digit codes (precision), the first three are significant. The EIA-96 system uses a two-digit code and a letter multiplier. This authoritative guide covers all calculation methods, updated for 2026 industry standards.What are SMD Resistors? (2026 Overview)SMD Resistor, also known as a Chip Resistor, is a surface-mount passive component essential for modern high-density electronics. Manufactured by sintering metal powder and glass glaze on a ceramic substrate, these components offer superior resistance to humidity, high temperatures, and vibration compared to legacy through-hole parts. As of 2026, they are the industry standard for everything from AI hardware to smartphones. While different resistors feature varied specifications, the critical question remains: how are these microscopic resistance values marked and decoded? Figure 1. Structure of SMD ResistorsⅠ How to Read Resistor Markings: 4 Key MethodsTo master resistor identification, one must understand the four global standards used to denote resistance values. These methods are governed by IEC 60062 standards:1. Direct Marking MethodThis method prints the actual numbers and unit symbols directly on the resistor surface. The allowable error (tolerance) is expressed as a percentage. If no deviation is marked, the standard tolerance is typically ±20%.2. Text Symbol MethodThis approach uses a combination of Arabic numerals and text symbols to indicate the nominal resistance and tolerance. The number preceding the symbol represents the integer value, while the number following represents the decimal. Tolerance characters are standardized: D (±0.5%), F (±1%), G (±2%), J (±5%), K (±10%), M (±20%).3. Digital Method (Most Common for SMD)This method uses a 3-digit or 4-digit code. Read from left to right, the initial digits represent the significant figures (effective values), and the final digit is the exponent (multiplier), indicating the number of zeros to add. The unit is always Ohms (Ω).4. Color Code Marking MethodWhile rare on modern SMDs (except MELF packages), color bands are the standard for through-hole resistors. The bands represent values and multipliers:Black (0), Brown (1), Red (2), Orange (3), Yellow (4)Green (5), Blue (6), Violet (7), Gray (8), White (9)Tolerance: Gold (±5%), Silver (±10%), Colorless (±20%)Figure 2. Universal Resistor Color Code DiagramReading Tip: For a four-band resistor, the last band (usually gold/silver) is the tolerance. The first two bands are digits, and the third is the multiplier. For five-band precision resistors, the first three are digits, the fourth is the multiplier, and the fifth is the tolerance. Ⅱ Calculating SMD Resistor Values (Step-by-Step)2.1 Understanding Character Code MarkingsVideo: SMD Resistor Coding ExplainedMarking chip resistors requires a compact system due to the component's microscopic size. While large packages may use full numbers, 0603, 0805, and 1206 packages use coded systems. Here is the 2026 standard breakdown for decoding these values:The 3-Digit System (Standard Tolerance ±5%):1. The first and second digits represent the significant resistance figures.2. The third digit is the multiplier (10^x).Decoding Guide by Third Digit:• Ends in 0: No extra zeros. Example: 100 = 10 Ω.• Ends in 1: Add one zero (x10). Example: 101 = 100 Ω.• Ends in 2: Add two zeros (x100). Example: 102 = 1,000 Ω (1 kΩ).• Ends in 3: Add three zeros (x1,000). Example: 103 = 10,000 Ω (10 kΩ).• Ends in 4: Add four zeros. Example: 104 = 100 kΩ.• Ends in 5: Add five zeros. Example: 105 = 1 MΩ.• Ends in 6: Add six zeros. Example: 106 = 10 MΩ.The 4-Digit System (Precision Tolerance ±1%):For higher precision, three significant digits are used. Example: 1001 means 100 + one zero = 1000 Ω (1 kΩ).Note: Ultra-small packages like 01005, 0201, and 0402 are physically too small for markings. These must be measured with a multimeter or tracked via reel tape labeling.2.2 Real-World Calculation ExamplesCase 1: 3-Digit Code (±5% Tolerance)This uses two significant digits followed by a multiplier.Calculation: 153 → 15 followed by 3 zeros → 15,000 Ω = 15 kΩDecimal Values: "R" represents the decimal point. Code 6R8 → 6.8 ΩCase 2: 4-Digit Code (±1% Tolerance)Common on packages like 0805, 1206, and 2512. The first three digits are significant.Calculation: 2372 → 237 followed by 2 zeros → 23,700 Ω = 23.7 kΩDecimal Values: 3R24 → 3.24 ΩCase 3: EIA-96 System (The "Cryptic" Code)Used for 1% tolerance resistors on small 0603 packages where 4 digits won't fit. This system uses a two-digit code (referencing a lookup table) and a letter multiplier.Format: [Code] [Letter]Example Multipliers: Y=0.01, X=0.1, A=1, B=10, C=100, D=1000, E=10000.E-96 Series Standard Resistance Lookup Table (Partial)ValueCodeValueCodeValueCode100011471721533102021501822134105031541922635107041582023236110051622123737113061652224338115071692324939118081742425540121091782526141124101822626742127111872727443130121912828044133131962928745137142003029446140152053130147143162103230948 ValueCodeValueCodeValueCode316494646568181324504756669882332514876771583340524996873284348535116975085357545237076886365555367178787374565497280688383575627382589392585767484590402595907586681412606047688792422616197790993432626347893194442636497995395453646658097696EIA-96 Calculation Examples:Code 29B: Lookup "29" in table → Value 196.Multiplier "B" → x10.Result: 196 × 10 = 1.96 kΩCode 10X: Lookup "10" in table → Value 124.Multiplier "X" → x0.1.Result: 124 × 0.1 = 12.4 ΩCase 4: The Underlined Code (Special 0603 Case)Sometimes you see a standard 3-digit code with a line under it on an 0603 package. This usually indicates the manufacturer uses the E-24 series values (loose tolerance) rather than E-96, but the calculation is standard.122 = 12 × 100 = 1.2 kΩ680 = 68 × 1 = 68 Ω (Note: 680 does not mean 680 ohms here, it means 68 and zero extra zeros). Ⅲ How to Identify Damaged SMD Resistor Values?When a resistor is burned or the marking is unreadable, use these four forensic engineering methods to deduce the value:1. Parallel Circuit ComparisonPCB designs, especially in power supplies and audio amplifiers, often use symmetrical channels. • Example: In an LCD backlight driver, if the resistor in Channel A is burnt, check the corresponding position in Channel B. Often R17 = R51, or R23 = R48. Measure the intact sibling component to find the value.2. Circuit Context Analysis (Pull-Up/Pull-Down)For Microcontroller (MCU) circuits, resistors connected to GPIO pins are typically "pull-up" or "pull-down" resistors used to stabilize logic levels.• Common Values: 3.3kΩ, 4.7kΩ, 10kΩ.• Deduction: If the resistor connects a data line to VCC or GND, replacing it with a 10kΩ resistor is a safe starting point for testing.3. Reference Similar SchematicsIf the exact schematic is unavailable, search for schematics of devices using the same main IC. Manufacturers often use the "Reference Design" provided by the chipmaker, meaning the peripheral resistor values will be identical across different brands.4. The Potentiometer Test (Advanced)If all else fails, trace the circuit diagram. Temporarily solder a high-value potentiometer (variable resistor) in place of the damaged part. Power on the device and slowly adjust the resistance while monitoring voltage levels until the circuit functions correctly. Remove the potentiometer, measure its set resistance, and replace it with the closest standard fixed resistor.  Ⅳ Top SMD Resistor Manufacturers (2026 Updated)Reliability is paramount in 2026 electronics. The following brands are currently recognized as Tier-1 manufacturers for automotive, industrial, and consumer electronics:YAGEO: Global leader in chip resistors (acquired KEMET).Vishay: Known for high-precision, military-grade foil resistors.Panasonic: Industry standard for high-reliability automotive parts.KOA Speer: Major supplier for automotive and industrial markets.Bourns: Famous for circuit protection and resistors.TE Connectivity: Specialist in harsh environment resistors.Other Notable Brands: ROHM, Ohmite, Welwyn, TT Electronics, UNI-ROYAL (Uniohm). ⅴ Frequently Asked Questions (FAQ)1. What is an SMD resistor used for?SMD (Surface Mount Device) resistors limit current, divide voltage, and stabilize signal lines in compact electronic circuits. They are essential for miniaturizing devices like smartphones, wearables, and IoT sensors where traditional through-hole components would be too bulky. 2. How do I calculate the value of a 3-digit SMD resistor?Use the formula: [1st Digit][2nd Digit] x 10^[3rd Digit]. For example, "103" means 10 x 10^3 (1000) = 10,000 Ohms or 10kΩ. 3. What does "R" mean in a resistor code like 4R7?The letter "R" represents the decimal point. It is used when the resistance value is too small to use a multiplier code. Therefore, 4R7 equals 4.7 Ohms. 4. What is the difference between 103 and 1002 markings?Both equal 10kΩ, but the marking indicates tolerance. "103" (3-digit) typically indicates ±5% tolerance. "1002" (4-digit) indicates higher precision, typically ±1% tolerance. 5. How do I read the cryptic "01A" or "29B" codes?These are EIA-96 codes for 1% precision resistors on small 0603 parts. You cannot read them directly; you must use an EIA-96 lookup table. The number refers to a value code, and the letter is the multiplier. 6. Why do some SMD resistors have no markings?Resistors in package sizes 0402, 0201, and 01005 are physically too small to print legible text. To identify these, you must measure them with a multimeter or refer to the manufacturer's reel tape packaging. 7. What does SMD stand for?SMD stands for Surface Mounted Device. It refers to the component itself. SMT (Surface Mount Technology) refers to the manufacturing process of placing these components onto a PCB. 8. What materials are SMD resistors made of?Most SMD resistors are "Thick Film" or "Thin Film" types. They consist of a ceramic substrate (alumina) coated with a resistive paste (metal oxides and glass). This is fired in a kiln, laser-trimmed to the exact value, and then coated with a protective layer.{ "@context": "https://schema.org", "@type": "Article", "mainEntityOfPage": { "@type": "WebPage", "@id": "https://www.kynix.com/Blog/How-to-Read-the-Value-of-SMD-Resistor-Example-Explained.html" }, "headline": "How to Read SMD Resistor Codes: The 2026 Guide to 3-Digit, 4-Digit & EIA-96 Markings", "image": "https://www.kynix.com/editor_u/image/20211027/2021102711243403.jpg", "author": { "@type": "Organization", "name": "Kynix Electronics" }, "publisher": { "@type": "Organization", "name": "Kynix Electronics", "logo": { "@type": "ImageObject", "url": "https://www.kynix.com/logo.png" } }, "datePublished": "2021-10-27", "dateModified": "2026-01-08", "description": "Learn how to calculate SMD resistor values using 3-digit, 4-digit, and EIA-96 codes. Includes updated 2026 lookup tables and troubleshooting steps for damaged components.", "articleBody": "SMD Resistor, called Chip Resistor, is one type of resistors..."}{ "@context": "https://schema.org", "@type": "FAQPage", "mainEntity": [{ "@type": "Question", "name": "What is an SMD resistor used for?", "acceptedAnswer": { "@type": "Answer", "text": "SMD (Surface Mount Device) resistors limit current, divide voltage, and stabilize signal lines in compact electronic circuits like smartphones and IoT devices." } }, { "@type": "Question", "name": "How do I calculate the value of a 3-digit SMD resistor?", "acceptedAnswer": { "@type": "Answer", "text": "Use the formula: [1st Digit][2nd Digit] x 10^[3rd Digit]. For example, 103 means 10 x 1000 = 10,000 Ohms (10kΩ)." } }, { "@type": "Question", "name": "What does 'R' mean in a resistor code like 4R7?", "acceptedAnswer": { "@type": "Answer", "text": "The letter 'R' acts as a decimal point. 4R7 represents 4.7 Ohms." } }, { "@type": "Question", "name": "How do I read EIA-96 codes like 01A?", "acceptedAnswer": { "@type": "Answer", "text": "EIA-96 codes require a lookup table. The number represents a significant value, and the letter represents a multiplier. For '01A', 01 is 100 and A is x1, resulting in 100 Ohms." } }]}{ "@context": "https://schema.org", "@type": "HowTo", "name": "How to Read a 3-Digit SMD Resistor Code", "description": "Step-by-step guide to calculating resistance from standard 3-digit markings found on most chip resistors.", "step": [{ "@type": "HowToStep", "name": "Identify the Significant Digits", "text": "Read the first two numbers on the resistor. These are your significant digits (e.g., in '103', the significant digits are '10')." }, { "@type": "HowToStep", "name": "Identify the Multiplier", "text": "Read the third number. This indicates the power of 10 to multiply by (or how many zeros to add). In '103', the multiplier is 3 (10^3 or 1000)." }, { "@type": "HowToStep", "name": "Calculate the Result", "text": "Multiply the significant digits by the multiplier. 10 x 1000 = 10,000 Ohms (10kΩ)." }]}

Ⅰ IntroductionOscillators are the heartbeat of modern electronics. From the quartz watch on your wrist to the 5G smartphone in your pocket, these components play a critical role in generating timekeeping signals and carrier waves. While early applications included simple AM radios and metal detectors, today's oscillators are foundational to IoT devices, advanced computing, and high-speed data transmission.To understand how electronic oscillators function in 2025, it helps to look at physical analogies and fundamental circuit designs. This guide covers the core concepts, modern classifications, and practical examples of oscillators in electronics.Ⅱ What is an Oscillator?An oscillator is an electronic circuit that converts direct current (DC) from a power supply into an alternating current (AC) signal—typically a sine wave, square wave, or triangle wave. They are ubiquitous in technology, found in everything from microcontrollers and music synthesizers to GPS receivers.Every oscillator contains at least one active device (such as a transistor or Op-Amp) that acts as an amplifier. The core operating principle relies on a feedback loop: an oscillator employs a sensitive amplifier where a portion of the output signal is fed back into the input in phase. This process, known as positive feedback, allows the signal to regenerate and sustain itself indefinitely, provided there is a power source.Ⅲ The Working Principle of an OscillatorFor an oscillator to sustain a frequency, energy must oscillate between two forms. The simplest way to visualize this is through a Tank Circuit, created by connecting a capacitor and an inductor in parallel.The Energy Cycle:Storage: Capacitors store energy in an electrostatic field, while inductors store energy in a magnetic field.Discharge: When a charged capacitor discharges through an inductor, the current creates a magnetic field around the inductor coil.Collapse & Recharge: As the capacitor fully discharges, the inductor's magnetic field collapses, inducing a current that recharges the capacitor (with opposite polarity).Oscillation: This back-and-forth transfer of energy creates an oscillation. In a perfect world, this would continue forever. In reality, internal resistance dissipates energy (damping), so an active component (amplifier) is required to inject energy and keep the oscillation going.Ⅳ Types of Oscillators4.1 General ClassificationWhile there are countless variations, oscillators generally fall into two primary categories:Harmonic (Linear) Oscillators: Energy flows from active to passive components to generate a purely sinusoidal waveform. The frequency is determined by a feedback path. These are crucial for radio frequencies (RF) and audio applications.Relaxation Oscillators: These operate by exchanging energy between active and passive components through charging and discharging phases. They produce non-sinusoidal shapes like square, saw-tooth, or triangular waves, commonly used in digital timing and signal processing.4.2 The 5 Basic TypesRC and LC Oscillators: Basic circuits using resistors/capacitors or inductors/capacitors to determine frequency.Crystal Oscillators: Use vibrating quartz crystals (and increasingly MEMS technology) for high-precision stability.Sinewave Oscillators: Circuits optimized to produce low-distortion sine outputs (e.g., Wien Bridge).Square Wave Oscillators: Circuits like the Multivibrator or 555 Timer used for clock pulses.Voltage Controlled Oscillators (VCO): The frequency output can be tuned by varying the input voltage.Ⅴ Details and Circuit Examples5.1 LC OscillatorsLC oscillators combine inductors and capacitors (a tank circuit) to generate high-frequency sine waves. They are preferred in Radio Frequency (RF) applications because they offer good phase noise performance and are easy to tune. In 2025, advanced LC tank circuits are still relevant in communication hardware, though they are often integrated into silicon chips.Figure 1: Basic LC Oscillator ConfigurationExample: Gated LC Phase Shift OscillatorThis circuit allows the oscillation to be turned on or off via a logic input. When the input is high (e.g., 5V), the oscillator runs; when grounded, it stops. This "burst" mode capability is useful in digital communication protocols.Figure 2: Gated LC Phase Shift Oscillator5.2 RC (or CR) OscillatorsAt low frequencies (like the audio range of 20Hz - 20kHz), inductors become large and impractical. Engineers solve this by using Resistors and Capacitors (RC) to set the frequency. While creating a pure sine wave with RC circuits is challenging, they are cost-effective and compact for audio signal generation.Figure 3: Basic RC OscillatorExample: CMOS 555 Timer & Schmitt TriggerEven decades after its invention, the 555 timer remains a staple in electronics. The modern CMOS versions consume less power and offer cleaner switching, making them ideal for battery-operated IoT sensor polling.Figure 4: 555 Timer based RC Oscillator5.3 Crystal OscillatorsCrystal oscillators utilize the piezoelectric effect of quartz to generate a frequency with immense stability. They act as the "heartbeat" for microprocessors. In recent years, MEMS (Micro-Electro-Mechanical Systems) oscillators have begun to replace quartz in some high-vibration environments, but quartz remains the standard for precision.Figure 5: Crystal Oscillator SchematicFor High-Frequency (HF) applications, a transistor like the 2N2222A (or modern surface-mount equivalents) is typically used. The tuned circuit matches the impedance, often loading at nominally 50 ohms. Modern designs frequently include a buffer amplifier stage to prevent the load from pulling the crystal off-frequency.5.4 Sinewave OscillatorsThe Wien Bridge Oscillator is a specific type of RC oscillator capable of generating very low-distortion sine waves. It is famous for being the first product designed by Hewlett-Packard (HP).Figure 6: Practical Wien Bridge Oscillator using a light bulb for stabilizationHistorical Note: The schematic above uses an incandescent light bulb for gain stabilization. As the bulb heats up, its resistance increases, stabilizing the feedback loop. In modern 2025 circuitry, this bulb is typically replaced by JFETs or automatic gain control (AGC) ICs for higher reliability and lower power consumption, though the bulb method remains an excellent educational example of negative feedback.5.5 Square Wave OscillatorsAlso known as Astable Multivibrators, these generate a digital on/off signal without external input. They are fundamental to digital logic clocks and PWM (Pulse Width Modulation) controllers.Figure 7: Multi-frequency Square Wave Generator using 555 Timer5.6 Voltage Controlled Oscillator (VCO)A VCO allows the frequency to be tuned dynamically by changing a control voltage. This is the core component of Phase Locked Loops (PLLs) used in Wi-Fi, Bluetooth, and cellular radios to lock onto specific frequencies.In the circuit below, a Varactor Diode is used. When reverse-biased, a diode acts like a capacitor; varying the voltage changes the capacitance, thus tuning the oscillator circuit without moving parts.Figure 8: Hartley Oscillator configuration for VCO applicationsⅥ Frequently Asked Questions (FAQ)1. What is the primary function of an oscillator?Oscillators convert a steady DC supply into a periodic AC signal. They provide the timing signals (clock) for computers, generate carrier waves for wireless transmission, and produce audio signals for synthesizers and alarms.2. How do you calculate oscillation frequency?For a simple pendulum or mechanical system, the formula is T = 2π√(m/k). In electronics (LC circuit), the resonant frequency is calculated as f = 1 / (2π√(LC)), where L is inductance and C is capacitance.3. What are the core components of an oscillator circuit?Most oscillators require three elements: 1. Tank Circuit/Network: Passive components (Inductors/Capacitors or Crystals) to set the frequency. 2. Amplifier: An active device (Transistor, Op-Amp) to gain power. 3. Feedback Loop: A positive feedback path to sustain the oscillation.4. What is the difference between an oscillator and an alternator?While both generate AC, an alternator is a mechanical device that converts mechanical energy into electrical energy (usually at low frequencies like 50/60Hz). An electronic oscillator is a solid-state circuit that converts DC electrical energy into high-frequency AC signals without moving parts.