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"What is the RMS Value of AC Circuits?" - "Ⅱ Determine RMS Value of AC Signals" -> "How to Determine the RMS Value of AC Signals" - "2.1 Sinusoidal Waveform" -> "How to Calculate RMS for a Sinusoidal Waveform" - "2.2 RMS Value Equation Steps" -> "What Are the Steps to Derive the RMS Value Equation?" - "2.3 RMS Mean on a Multimeter" -> "How Do Multimeters Measure RMS?" - "2.4 The Other Waveform" -> "How to Calculate RMS for Other Waveforms"- Missing or improvable schema types detected: Article, FAQPage, HowTo (for the equation steps).- Sections with vague/unsupported claims: "Nowsaday many electrical appliances, e.g. adjustable speed drives, tend to introduce harmonics..." (Updated with 2026 context on IEEE 519 and ASDs).- Estimated content freshness score: 4/10-->IntroductionSummary: The Root Mean Square (RMS) value of an alternating current (AC) signal represents the equivalent direct current (DC) voltage that produces the same heating effect across a resistor. This 2026 guide explains how to calculate RMS voltage for sinusoidal and non-sinusoidal waveforms, details the mathematical derivation steps, and explores why RMS is the standard measurement for AC power delivery.The RMS (Root Mean Square) value of any time-varying signal is directly related to the amount of heat being produced in a circuit or across a specific electrical element. If you need to know how to calculate the root mean square or RMS voltage of a sine wave given the peak voltage, this article provides the exact formulas. We will help you calculate the RMS value of AC circuits and provide the step-by-step process to derive the formula using basic math and calculus.What is RMS Value? | Easiest ExplanationCatalogIntroductionⅠ RMS Value of AC CircuitsⅡ Determine RMS Value of AC Signals2.1 Sinusoidal Waveform2.2 RMS Value Equation Steps2.3 RMS Mean on a Multimeter2.4 The Other WaveformWhat is the RMS Value of AC Circuits?The RMS value represents the effective direct current (DC) equivalent of a given alternating current (AC) signal that produces the exact same amount of heat and power across a specific circuit element. In electrical engineering, the physical meaning of RMS is the effective voltage value of an AC signal used to perform work. The work done in the process of converting electric current into other forms of energy is called electrical work, which depends on current, voltage, and energizing time.The higher the voltage applied to electrical appliances, the greater the energized current, and the longer the energizing time, the more work the current will do. The RMS value is also called the effective value because it is evaluated from the perspective of electrical work.The effective value of alternating current equals the DC voltage that obtains the same power consumption (heating) on an identical resistance.Because AC fluctuates, the correct result must be obtained after time averaging (integration).The instantaneous value of direct current cannot be used to replace the effective value.In statistical data analysis, the square of all values is summed, the mean value is calculated, and finally, the square root is taken to obtain the root mean square value.Figure 1. Peak to Peak VoltageIn physics, we often use the RMS value to analyze the noise of a power supply. When the voltage of the resistor is the AC voltage V(t), the power V²/R changes with time. If the energy consumed per cycle is divided by the number of cycles, this is the average power. Furthermore, if the power of a DC voltage applied to the same resistor is the same as the average power of the AC voltage, the DC equivalent voltage is the root-mean-square value of the AC voltage. How to Determine the RMS Value of AC SignalsLiterally, RMS means take the SUM, get the MEAN, and then take the ROOT; in that order, and you'll get the RMS value. As shown here, the general equation of RMS value has been derived, which can be used to find the RMS value of any time-varying signal. Just obey the rules.How to Calculate RMS for a Sinusoidal WaveformTo calculate the RMS voltage of a pure sinusoidal waveform, you multiply the peak voltage by 0.7071 (or divide by the square root of two). The following formulas apply strictly to PURE sine wave signals. In 2026, the widespread use of non-linear loads like adjustable speed drives (ASDs) and LED lighting frequently introduces harmonic distortion into electrical systems, meaning real-world signals are rarely pure sine waves.Calculate the effective value from the definition, that is, alternating current and direct current respectively pass through the same resistor. If the two consume the same electric energy (or produce the same Joule heat) in the same time, then the direct current value is called the effective value of the alternating current. The accumulation of signal power over time is the work done by the signal. The most primitive is derived for sine waves, but in fact, it is applicable to all waveforms.Use definite integral to calculate the work by the AC signal in the load R at one cycle. It is equal to the work done by a DC quantity (effective value) in one cycle of the load R.VR:  Instantaneous power of R: Average power of R: The power of the stable DC voltage Vdc is , if this power is the same as the average power of AC, thenWhere, Vdc is called the RMS value of the AC signal (Vrms)With Vrms, calculate the average power of the load resistor R:The RMS voltage calculation is ultimately used to give a measure of the average continuous power carrying capability of a signal. The instantaneous voltage values are squared (the V² term) which is then summed up (the integration) before converting back to voltage by the square root operation. Once the RMS voltage value is known, then you can make accurate estimates on true power delivery over time, independent of the signal's polarity.To put it simply, for example, a square wave signal with an amplitude of 100V and a duty cycle of 0.5, if calculated based on the average value, its voltage is only 50V, and calculated according to the root mean square value is 70.71V. Why is this? For example, there is a set of 100-volt battery packs, which will stop for 10 minutes after each power supply for 10 minutes, which means that the duty cycle is half. If this batteries set drives a 10Ω resistor, 10A of current and 1000W of power will be generated in 10 minutes, and the current and power will be zero during a power failure.Then in a period of 20 minutes, the average power is 500W, which is equivalent to the power generated by 70.71V charging a 10Ω resistor directly. The 50V DC voltage can only produce 250W of power when charges a 10Ω resistor. For motors and transformers, as long as the root mean square current does not exceed the rated current, they will not burn out even if they are overloaded within a certain period of time.What Are the Steps to Derive the RMS Value Equation?To calculate the RMS of a time-varying signal y(t), you must square the function, find its mean over one complete period, and take the square root. The exact mathematical steps are as follows:Square the waveform: Calculate the square of the instantaneous signal, y²(t).Find the mean: Take the average (integral) value of y²(t) over one complete period.Take the root: Calculate the square root of that average value to find the final RMS figure.Example:(1) a2 is a constant, so .(2) cos(ωt) is a complete cosine curve.(3)How Do Multimeters Measure RMS?Most standard multimeters measure the peak voltage of an AC signal and automatically multiply it by 0.707 to display the RMS value, assuming a pure sine wave. In daily life, ordinary voltmeters are scaled according to this effective value of the sine wave.Effective Value: The effective value of the sine wave is U = maximum Um × 0.707.Average Value: The average value is generally not used for power calculations; it refers to the average of each instantaneous value in the positive or negative half cycle. The average value of the sine wave is Up = Maximum Um × (2/π) = 0.637Um.Note that measuring alternating current with a standard voltmeter is strictly based on the sine wave effective value scale. If you are measuring a non-sine wave, such as a square or pulse wave, a standard meter reading is inaccurate. You must use a "True RMS" multimeter for distorted waveforms.How to Calculate RMS for Other WaveformsDifferent waveform shapes require different mathematical constants to calculate their RMS values accurately. Below are the derivations for half-sinusoidal and square waves.Waveform TypeRMS Voltage FormulaAverage Voltage FormulaPure Sine Wave0.707 × Peak0.637 × PeakHalf Sine Wave0.500 × Peak0.318 × PeakSquare Wave1.000 × Peak1.000 × Peak1) Half Sinusoidal Waveform2) Square WaveWhen we want to average the electrical signal, if the process is completed over the entire period or less, we need to give accuracy. For basic and symmetrical AC signals, regardless of frequency, peak value or period, averaging over a complete period always results in 0V. Therefore, it is more appropriate to average these signals during the half period.In short, average voltage tells you that your voltage fluctuates around some average value, while RMS voltage shows you how much is that fluctuation. In addition, Square of RMS could be understood as the average power on a resistor of 1 Ohm. ↪️Recommended RMS Value Calculation Tool: RMS Voltage Calculator – From Average Value, Peak & Peak to Peak Value Frequently Asked QuestionsWhat does RMS stand for in electronics?RMS stands for Root Mean Square. In electronics, it is a mathematical method used to determine the effective direct current (DC) equivalent of an alternating current (AC) signal. The RMS value represents the exact amount of AC voltage required to produce the same heating effect as a steady DC voltage.How do you calculate the RMS voltage of a sine wave?To calculate the RMS voltage of a pure sine wave, multiply the peak voltage by 0.7071 (which is one divided by the square root of two). For example, an AC signal with a peak voltage of 170V has an RMS voltage of approximately 120V.Why is RMS voltage used instead of average voltage?RMS voltage is used because the true average voltage of a complete AC sine wave cycle is zero, as the positive and negative halves cancel each other out. RMS squares the instantaneous values, making them all positive, which accurately reflects the signal's true power delivery capability.What is the difference between RMS and peak power?RMS power represents the continuous, average power an amplifier can output or a speaker can handle over a long period without distortion or damage. Peak power is the absolute maximum burst of power a device can handle for a fraction of a second. RMS is the more reliable metric.{ "@context": "https://schema.org", "@graph":[ { "@type": "Article", "headline": "RMS (Root Mean Square) Value of AC Circuits", "datePublished": "2021-07-02T15:10:32Z", "dateModified": "2026-03-14T15:51:00+08:00", "author": { "@type": "Organization", "name": "ApogeeWeb" }, "publisher": { "@type": "Organization", "name": "ApogeeWeb", "logo": { "@type": "ImageObject", "url": "https://www.apogeeweb.net/favicon.ico" } } }, { "@type": "FAQPage", "mainEntity":[ { "@type": "Question", "name": "What does RMS stand for in electronics?", "acceptedAnswer": { "@type": "Answer", "text": "RMS stands for Root Mean Square. In electronics, it is a mathematical method used to determine the effective direct current (DC) equivalent of an alternating current (AC) signal. 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IntroductionAs everyone knows, Error correction code memory (ECC memory) is a type of computer data storage technique. It identifies and fixes the most common errors which could otherwise lead to data corruption or system crashes. In other words, it is one of the most important techs for this loss and system errors prevention. There will be people who have such a question: now the memory technology is improved greatly, it’s possible to use ECC server RAM inside of your regular desktop computer at home, but is it something you SHOULD do? This note will help you find clues step by step.ECC Memory ExplainedCatalogIntroductionⅠ What Causes Errors in RAM?Ⅱ Is ECC RAM Better?Ⅲ ECC Server RAM or Regular Home Desktop?Ⅰ What Causes Errors in RAM?The ram error is caused by electromagnetic interference inside the computer. This interference will cause the units of DRAM (Dynamic Random Access Memory) to spontaneously change to the opposite state. Unit errors may be hidden, that is, they will not have a serious impact on the data. However, the memory units are interrelated, so unit changes may affect the entire operating system, resulting in system errors, especially when the strict operation is required. To be specific, memory errors will cause security vulnerabilities, crashes, transcription errors, lost transactions and corrupted or lost data, and one of the most common types of memory error is a single-bit error.Ⅱ Is ECC RAM Better?In the face of these problems, if memory can fix the error itself, what will it look like? That is ECC RAM.Memory Chips DifferenceECC RAM is server memory. This type of memory module has an ECC error check storage chip (the number of storage chips is an odd number). The application of ECC can ensure that the server is safer and more stable during operation. However, the number of chips stored in ordinary memory sticks is even. In reality, ECC RAM has 9 memory chips instead of 8. Error Checking and CorrectingThe ECC memory is equipped with ECC error-checking technology. After error checking and correction, the stability and reliability of the server system can be effectively guaranteed. For ordinary ram, when the word detects an error, the error location cannot be determined, and the error cannot be corrected. Therefore, for a single task that takes a long time and cannot be suspended or error, ECC memory is an inevitable choice. However, ordinary PCs will not use because of high-cost price. Application DifferenceBecause ECC memory can effectively store and maintain data integrity and is equipped with check and correction technology, ECC memory further reduces data corruption. Therefore, it is mostly used in servers and graphics workstations such in financial and scientific industries. Non-ECC memory sticks are more suitable for the general public's use. Capacitor DifferenceAs server memory applications require higher capacity, ECC memory modules usually start at 4GB, while ordinary memory modules usually start at 2GB. The standard configuration on home computers is 4~8GB of memory. Price DifferenceDue to the higher-tech of ECC memory sticks, their capacity is also larger than ordinary memory. Therefore, ECC memory sticks are more expensive than ordinary memory.Ⅲ ECC Server RAM or Regular Home Desktop?ECC memory is usually used in servers or graphics workstations. Because of the check and correction function, when there are some read and write errors in the memory, the ECC RAM can correct these errors and reduce the probability of downtime/blue screen. Guaranteed data storage and accuracy of reading and writing.Server memory and ordinary PC memory are very similar, there is no obvious difference in appearance and structure, but its price is higher than ordinary memory. There are three main types of server memory: SDRAM, DDR, and DDR2. At present, server memory is mostly used by DDR and DDR2. As time goes by, the server uses some new technologies now, such as ECC, chip kill, register, hot-swap technology, FB-DIMM (full buffer memory module), etc. More server memory currently adopts ECC and REG ECC technologies. The chips on REG ECC memory are generally 2-3 more than ordinary motherboards, mainly PLL (phase-locked loop) and Register IC. ECC and ECC REG memory have been developed for a period, and the frequency mainly has 133, 266, 333, 400, 533, and 667 stages. What is RECC? The specific uses of RECC memory are as follows: phase-locked loop chip, the bottom of the memory stick are smaller than Register ICs. Generally, there is only one, which can adjust the clock signal and ensure signal synchronization between the memory modules. The smaller IC chip (2-3 pieces) at the bottom plays a role in improving the driving capability. Server products need to support large-capacity memory. The motherboard alone cannot drive such a large-capacity memory. Instead, the memory module with Register is used to improve the driving ability, so that the server can support up to 32GB of memory. Because of the PLL and Register chips, the server memory capacitor can be made very large, it can better meet the endless requirements of the ever-increasing software for memory. Therefore, it is recommended that the server whose requirement is over 16G use RECC RAM.RECC has one more register. We can understand the function of the memory as a book directory. When the memory receives a read and write command, it will retrieve this directory first, and then perform read and write operations, which will greatly improve the efficiency of the server memory. So some people mistakenly think that RECC RAM runs slower than ECC RAM. The Register memory that can be used at present also has an ECC function, and some motherboards require the memory to support Register. In fact, all registered memory is ECC memory. The use of ECC memory requires the support of other computer components, such as the motherboard and cpu, and may also need to be set in the BIOS before it can be used on most server CPUs and motherboards (some non-server CPUs and motherboards also support). In addition, when purchasing ecc memory, you need to pay attention to whether it is ecc udimm or ecc rdimm or ecc lrdimm or ecc 3ds rdimm or something else. Because your computer configuration may not support some types.What’s more, all of the modern, contemporary storage drives use ECC at some level internally. HDD, SSDs. The data densities of the HDD push the edge where need to keep up with track integrity. NAND in SSDs tend to loose data bits in usage over time. The SSD controller in the T2 isn't remarkable on the ECC dimension. All the ones that store the data encrypted 'at rest' basically have to if going to be competently implemented. In addition, ECC generally works on all Ryzen Chips minus the APUs (with the exception of the pro apus), they tend to not be on the QVL since it costs time and money to do that. Frequently Asked Questions about ECC Server Memory1. What is ECC memory?Error correction codeError correction code (ECC) memory is a type of RAM memory found in workstations and servers. It's valued by professionals and businesses with critical data for its ability to automatically detect and correct memory errors, thus fighting data corruption. 2. Which is better ECC or non-ECC memory?Non-ECC (also called non-parity) modules do not have this error-detecting feature. ... Using ECC decreases your computer's performance by about 2 percent. Current technology DRAM is very stable, and memory errors are rare, so unless you have a need for ECC, you are better served with non-parity (non-ECC) memory. 3. How does ECC memory work?ECC memory uses the extra bits to store an encrypted code when writing data to memory, and the ECC code is stored at the same time. ... As data is processed, ECC memory is constantly scanning code with a special algorithm to detect and correct single-bit memory errors. 4. What is the benefit of ECC memory?ECC memory protects your system from potential crashes and inadvertent changes in data by automatically correcting data errors. This is achieved with the addition of a ninth computer chip on the RAM board, which acts as an error check and correction for the other eight chips. 5. Who needs ECC RAM?Error-correcting code memory (ECC memory) is a type of computer data storage that can detect and correct the most common kinds of internal data corruption. ECC memory is used in most computers where data corruption cannot be tolerated under any circumstances, such as for scientific or financial computing.

IntroductionThe mass air flow sensor, also known as the air flow meters, is one of the important sensors of the electronic jet engine. It converts the inhaled air flow into electrical signals and sends them to the Electronic Control Unit (ECU). As one of the basic signals to determine fuel injection, it is a sensor to measure the inhaled air flow into the engine.      CatalogIntroductionCatalogⅠ OverviewⅡ Structural PrincipleⅢ The Structure of the Valve Type Air Flow SensorⅣ Karman Scroll Air Flow SensorⅤ Measuring RangeⅥ Detection PrincipleⅦ Ultrasonic Karman Vortex Air Flow SensorⅧ Karman Vortex Type Air Flow Sensor for Pressure Change DetectionⅨ FAQⅠOverviewIn order to obtain the best concentration of the mixture under various operating conditions, the electronically controlled gasoline injection engine must accurately measure the amount of air inhaled into the engine at each moment, which is the main basis for the ECU to calculate (control) the amount of fuel injection.  If the air flow sensor or circuit fails and the ECU does not get the correct intake signal, it will not be able to control the fuel injection properly, which will cause the mixture to be too thick or too thin, and the engine will not operate properly. There are many types of air flow sensors in the electronic controlled gasoline injection system. According to their structure types, the common air flow sensors can be divided into blade (wing) type, core type, hot-wire type, hot film type, Karman vortex type, etc.                     Ⅱ Structural PrincipleIn the electronic controlled fuel injection device, the mass air flow sensor, which measures the amount of air absorbed by the engine, is one of the important components to determine the control precision of the system. When the control precision of the air-fuel ratio (A/F) of the air and mixture inhaled by the engine is specified as ±1.0, the allowable error of the system is ±6[%]~7[%]. When the allowable error is distributed to each component of the system, the allowable error of the air flow sensor is ±2[%]~3[%]. The ratio of the maximum value to the minimum value of the air flow rate inhaled by a gasoline engine is 40-50 in a natural intake system, and 60-70 in a supercharged system. In this range, the air flow rate of the sensor should be able to maintain a measurement accuracy of ±2~3[%]. The air flow sensor used in the electronic control fuel injection device should not only maintain the measurement accuracy over a wide measurement range, but also have excellent measurement response and can be measured. For pulsating air flow, the output signal processing should be simple. According to the different characteristics of the air flow sensor, the fuel control system is divided into L-type control for direct measurement of air intake volume and D-type control for indirect measurement of air intake volume (indirect measurement of air intake according to the negative pressure of the intake manifold and the engine speed).                                                           The microcomputer ROM in the D-type control mode stores in advance the intake air volume under various conditions based on the engine speed and the pressure in the intake pipe. The microcomputer is based on the measured operation. The intake pressure and speed in the state, referrring to the intake volume memorized by ROM, can calculate the fuel volume. The air flow meter used for L-type control is basically the same as the general industrial flow sensor, but it can adapt to the harsh environment of the car, but it is the response requirements for the rapid changes in the flow rate that occur during the throttle and the requirements for high-precision detection in the uneven airflow caused by the shape of the intake manifold before and after the sensor. The original electronic fuel injection control system did not use a microcomputer. It was an analog circuit. At that time, a valve-type air flow sensor was used, but several other air flow sensors emerged as microcomputers were used to control fuel injection.Ⅲ The Structure of the Valve Type Air Flow SensorThe valve type air flow sensor is mounted on the gasoline engine and installed between the air filter and the throttle. Its function is to detect the air intake of the engine and convert the detection results into electrical signals, which are then input into the microcomputer. The sensor is composed of an air flow meter and potentiometer. Look at the working process of the air flow sensor first. The air drawn in by the air filter rushes to the valve, and the valve turns to stop at the position where the intake is balanced by the return spring. In other words, the opening of the valve is proportional to the intake.  A potentiometer is also installed on the rotating shaft of the valve, and the sliding arm of the potentiometer rotates synchronously with the valve. The voltage drop of the sliding resistance is used to convert the opening of the measuring piece into an electrical signal, which is then input into the control circuit.Ⅳ Karman Scroll Air Flow SensorIn order to overcome the shortcomings of the valve type air flow sensor, that is, under the premise of ensuring measurement accuracy, expanding the measurement range and eliminating the sliding contact, a small and lightweight air flow sensor has been developed, namely the Karman Vortex Air Flow Sensor. The Karman vortex is a physical phenomenon. The vortex detection method and electronic control circuit have nothing to do with the detection accuracy. The air path area and the size change of the vortex column determine the detection accuracy. Because the output of such a sensor is an electronic signal (frequency), the AD converter can be eliminated when the signal is input to the control circuit of the system. Therefore, in essence, the Karman vortex air flow sensor is a signal suitable for microcomputer processing. This sensor has the following three advantages: high test precision, which can output linear signal and signal processing is simple; long-term use and performance will not change; because it detects volume flow, it does not need to correct temperature and atmospheric pressure.                                     The principle of flow detection of this air flow sensor is that when a Karman vortex is generated, it follows the change of speed and pressure. The basic principle of flow detection is to make use of the velocity change. The signal waveform output from the air flow sensor to the control module is shown in the figure. The signal is a square wave and a digital signal. The more air intake, the higher the frequency of the Karman vortex, and the higher the frequency of the output signal of the air flow sensor. The temperature and pressure compensation air flow sensor, mainly used for industrial pipeline flow measurement of medium fluid, such as gas, liquid, vapor and other media. It is characterized by small pressure loss, large range, high precision, and is almost unaffected by fluid density, pressure, temperature, viscosity and other parameters when measuring volume flow in working conditions.Features of the Karman Vortex Flow Meter                                There are no movable mechanical parts, so the reliability is high and the maintenance is small. The instrument parameters can be stable for a long time. This instrument adopts piezoelectric stress sensor, which has high reliability and can work in the working temperature range of -10℃~+300℃. There are analog standard signals and digital pulse signal outputs, which are easy to use with digital systems such as computers. It is a relatively advanced and ideal flow. The biggest advantage of the air flow sensor is that the meter coefficient is not affected by the physical properties of the measuring medium, and can be extended from a typical medium to other mediums. However, the frequency range is also very different because of the great difference between liquid and gas velocity ranges. In the amplifier circuit that processes the vortex signal, the passband of the filter is different, and the circuit parameters are also different. Therefore, the same circuit parameter cannot be used to measure different media.Ⅴ Measuring Range             Ⅵ Detection PrincipleOverhead power lines in the field whine when blown by the wind. The higher the wind speed is, the higher the sound frequency will be. This is because the air flows through the wire and forms a vortex. This phenomenon can occur in liquid, gas and other fluids, which can be used to make a vortex flow sensor. After the column is placed in the tube, two rows of vortices are formed, and the flow rate can be measured according to the frequency of occurrence of the vortices. Because the vortex turns into two parallel rows and alternates left and right, similar to the street lights on both sides of the street, it is called the vortex street. Because this phenomenon was first discovered by Karman, it is also called Karman Vortex Street.                                  Karman Vortex StreetⅦ Ultrasonic Karman Vortex Air Flow SensorThe ultrasonic air flow sensor is provided with two intake channels, the main channel and the side channel. The detection part of the intake flow is located on the main channel. The purpose of setting the side channel is to adjust the flow of the main channel so as to make the detection characteristics of the main channel present an ideal state. That is to say, for engines with different exhaust volume, one specification of air flow sensor can be used to cover a variety of engines by changing the cross-section size of the air flow sensor channel. The Karman vortex generator is composed of triangular columns and several vortex amplifiers on the main channel. On both sides of the place where the Karman vortex is generated, the ultrasonic transmitter and the ultrasonic receiver belonging to the electronic detection device are arranged oppositely. These two components can also be classified into the sensor. The electrical signal generated by the two electronic sensors is passed through the air. The control circuit (hybrid integrated circuit) of the flow sensor is shaped and amplified into an ideal waveform, and then input to the microcomputer. In order to detect vortices by ultrasound, sound-absorbing materials are glued to the inner wall of the vortex channel to prevent irregular reflections of ultrasonic waves.Ⅷ Karman Vortex Type Air Flow Sensor for Pressure Change DetectionThe vortex occurs alternately from both ends of the vortex generator, so the pressure at both ends of the vortex generator also alternately changes. This pressure change is guided to the mirror cavity through the pressure guide hole on the cone-shaped column on the downstream side of the vortex generator. In the mirror cavity, the mirror in the mirror cavity is tensioned with a very thin tension band, so distortion and vibration appear on the tension band. In addition, a leaf spring is used to apply appropriate tension to the tension band. Pressure changes other than vibration and scroll pressure are difficult to affect, so stable torsion and vibration can be obtained. The pressure formed by the vortex passes through the pressure guide hole to the reflector cavity, and the pressure changes synchronously with that in the reflector, and the reflector twists and vibrates in the tension band. The reflector is very lightweight and can operate even at low flow rates and very small pressure changes. On the upper part of the reflector, a light sensor composed of light-emitting diodes and phototransistors is correspondingly arranged. When the light emitted by the diode is reflected by the reflector and hits the phototransistor, it will become a current and output after the waveform circuit.Ⅸ FAQ1. What is the difference between the MAF sensor and the oxygen sensor?The MAF is the Mass Air Flow sensor and just as the name implies the sensor measures the mass of air going into the engine at the sensor (this is important because vacuum leaks or unmetered air is unaccounted for on the MAF sensor). Typically it uses a heated element and the air moving across the element cools it to "measure" the incoming air, however, vane style meters existed in the earlier days of electronic fuel injection. There are upstream and downstream oxygen sensors. The upstream sensor is responsible for checking the exhaust output of the engine. If there is too much fuel left in the exhaust the O2 sensor sends that information to the ECU and it will "trim" it out. If the O2 sensor samples the exhaust and there is too much oxygen in the exhaust stream then the sensor sends that info to the ECU and it will command more fuel. The downstream O2 sensor is present to monitor the condition of the catalytic converter(s). If it is out of range the ECU will flag it and the check engine light will illuminate. This is a very simple, quick, overview of the sensors but should give you a basic idea of their operation. 2. What are the symptoms of a bad mass airflow sensor?A faulty mass airflow sensor will cause problems similar to low compression or low vacuum, and will also show symptoms similar to when your vehicle has low fuel pressure from a faulty fuel pump. Here are some of the most common symptoms of a faulty mass airflow sensor:The engine is very hard to start or turn overThe engine stalls shortly after startingThe engine hesitates or drags while under load or idleHesitation and jerking during accelerationThe engine hiccupsExcessively rich or lean idling 3. How does a MAF sensor work?Installed in the intake pipe between the air filter housing and the intake manifold, most MAF sensors work on the hot wire principle. Put simply, a MAF has two sensing wires. One is heated by an electrical current, the other is not. As air flows across the heated wire, it cools down. When the temperature difference between the two sensing wires changes, the MAF sensor automatically increases or decreases the current to the heated wire to compensate. The current is then changed to a frequency or a voltage that is sent to the ECU and interpreted as airflow. The quantity of air entering the engine is adjusted accordingly. 4. Can a car run without a mass airflow sensor?Well, the answer to that is no. If you disconnect the mass airflow sensor, then the car should keep running and still be able to start normally. This means that if your mass airflow sensor dies completely, then your car will stay running and surprisingly the car might run better without the mass airflow sensor. 5. Why a MAF sensor needs to be replaced?If the sensor gets dirty, it won’t be able to read the airflow. When the MAF sensor doesn’t work, the engine may idle roughly, hesitate, and have difficulty starting. It may even stall on you while driving, which is no fun. The most common cause for the sensor to become dirty is an air filter that doesn’t get replaced when needed. When the air filter is clogged, it allows more dirt and debris to slip by and accumulate on the sensor. Routine maintenance and air filter replacement can extend the life of your MAF sensor and ensure it continues to work correctly. While the exact timing varies based on where and how much you drive, a good rule to follow is every 10,000 to 12,000 miles. 6. What will a bad mass airflow sensor do?A contaminated or failed mass air flow sensor cannot measure the amount of air flow correctly. This causes the engine computer to miscalculate the amount of injected fuel. As a result, a bad mass air flow sensor causes various driveability problems, including a no-start, stalling, lack of power and poor acceleration. 7. Will a bad mass airflow sensor cause a misfire?If an oxygen sensor or mass airflow sensor is failing, it could give incorrect data to your engine's computer, causing the misfire. When a vacuum line is broken, it can cause a fuel-injected motor to misfire. ... Replacing a vacuum line that's gone bad can potentially resolve the misfire. 8. How long does it take for the mass air flow sensor to reset?When you change a MAF sensor, you need to disconnect the battery for about 10 minutes so the computer forgets the learned parameters and resets to the factory parameters. Then it goes into learn mode and may take a little while before it learns all the parameters of the new MAF sensor. 9. How long can I drive with MAF unplugged?When you unplug the MAF, the computer goes to a default value stored in your memory. Your fuel economy will probably suffer a little bit, but no big issues. You're OK for a week or two, but replace the MAF with a proper TDI unit. The long-term effect is that the car does not operate to its full potential. 10. Can you bypass a MAF sensor?There is a sensor on the air intake called the mass air flow sensor. This sensor calculates how much air to mix with the fuel. You can bypass the MAF sensor, and allow the O2 sensor to calculate how much air is needed. 

IntroductionSeries Circuits and Parallel Circuits are main circuit connections, also a third type of circuit involves the dual use of series and parallel connections in a circuit. Circuit connection is a kind of principle for layout diagram that shows the relationship between components drawn by physical and electrical standardized symbols for research and engineering planning. As we all know, there are two types of circuit we can make, called series and parallel. They provide solutions for analyzing performance, installing electronic and electrical products.CatalogIntroductionⅠ Series Circuits and Parallel CircuitsⅡ Series Circuits and Parallel Circuits Calculation2.1 Resistors2.2 Capacitors2.3 Inductor2.4 Switch2.5 Power Supply2.6 Series and Parallel Circuits RulesⅢ Six Circuit Design Software Tools Introduction3.1 Protel PCB Design Platform3.2 Altium Designer3.3 Quartus II3.4 Electronics Workbench (EWB)3.5 NI Multisim3.6 Allegro PCBⅣ Frequently Asked Questions about Series and Parallel CircuitsⅠ Series Circuits and Parallel CircuitsWhat is the difference between series and parallel circuits? Just have a look of the following video and words description about series circuits and parallel circuits to get the basics and differences of them.Series vs Parallel CircuitsSeries connection is one of the basic ways to connect circuit elements. The circuit formed by connecting various electrical parts in series. In the series circuit, the current through each part is equal.Parallel connection is another connection method between electrical components. Components connected in parallel are connected in multiple paths so that the current can split up, and the same voltage is applied to each component.Ⅱ Series Circuits and Parallel Circuits Calculation👉 Resistors in Series and Parallel Circuits2.1 ResistorsResistors in SeriesAs shown in the figure, n resistors connect in series. Now connect the power supply to both ends of this series circuit. According to Kirchhoff’s current law, the current given from the power supply is equal to the current through each resistor, so .According to Ohm’s law, the voltage across the k-th resistor is equal to the current through multiplied by its resistance .According to Kirchhoff’s voltage law, the voltage across the power supply is equal to the algebraic sum of the voltage across all resistors.Therefore, the equivalent resistance Req of n resistors in series is .According to Ohm’s law, the voltage across the power source is equal to the given current times the equivalent resistance .Pay attention to the voltage shared by the resistors of the series circuit is proportional.Conductance G is the reciprocal of resistance R, so the equivalent conductance of n resistors in series is Among them, Gn is the conductance of the n-th resistor.For the simple case of two resistors in series, the equivalent conductance is .Resistors in ParallelWhen linear resistors connect in parallel, the conductance (the reciprocal of resistance) is equal to the sum of the conductances of the parallel resistors, which is called the equivalent conductance, and the reciprocal is called the equivalent resistance. For example, the resistances of R1, R2, and R3, their conductances are G1, G2, and G3, respectively. The total resistance R and total conductance G of the parallel circuit are calculated according to the formula .Note: Calculate the total series and parallel resistance of a circuit using Apogeeweb's Parallel and Series Resistor Calculator. 👉 Capacitors in Series and Parallel Circuits2.2 CapacitorsCapacitors in SeriesAs shown in the figure, n capacitors are connected in series. From the definition of capacitor, it can be obtained that the current passing through the k-th capacitor is equal to its capacitance multiplied by the voltage change rate across it:According to Kirchhoff’s current law, the current i given from the power source (ac or dc) is equal to the current passing through each capacitor, so According to Kirchhoff’s voltage law, the voltage across the power supply is equal to the algebraic sum of the voltage across all capacitors:The voltage change rate of the power supply end is .Therefore, the equivalent capacitance Ceq of n capacitors in series is Each capacitor has a “voltage rating” set by its manufacturer. Assuming that the working voltage exceeds the voltage rating of the capacitor, it may cause capacitor failure. In order to avoid it, several similar capacitors can be connected in series to make the algebraic sum of the voltage rating greater than the operating voltage. However, this will also reduce the equivalent capacitance of the circuit.Capacitors in ParallelAs shown in the figure, n capacitors are connected in parallel. From the definition of capacitor, it can be obtained that the current ik through the k-th capacitor is equal to its capacitance Ck multiplied by the voltage change rate across it:According to Kirchhoff’s voltage law, the voltage across the power supply is equal to the voltage across each capacitor:According to Kirchhoff’s current law, the current given from the power source (dc or ac) is equal to the algebraic sum of the current through each capacitor: Therefore, the equivalent capacitance Ceq of n capacitors in parallel is .Note: Calculate the total series and parallel capacitance of a circuit using Apogeeweb's Series and Parallel Capacitance Calculator. 👉 Inductors in Series and Parallel Circuits2.3 InductorInductor in SeriesAs shown in the figure, n inductors are connected in series. According to the method described above, the equivalent inductance can be calculated as .Among them, Ln is the inductance of the n-th inductor.The magnetic field generated by the inductor will be coupled with the winding coil of the adjacent inductor. So it is difficult to avoid the mutual influence of the adjacent inductors. The mutual inductance M of physical quantities can give a measure of this influence.A series circuit composed of two inductors L1 and L2, and the mutual inductance Ms.1) Assuming that the magnetic fields or fluxes generated by two inductors are in the same direction, the equivalent mutual inductance Leq is expressed by the equation: 2) Assuming that the magnetic fields or fluxes generated by two inductors are in opposite directions, Leq is expressed by the equation:For a parallel circuit with three or more inductors, it is necessary to consider the self-inductance of each inductor and the mutual inductance among the inductors, which makes the calculation more complicated. The equivalent inductance is the algebraic sum of all self-inductance and mutual inductance.For example, a series circuit composed of three inductors will involve three self-inductances and six mutual inductances. The self-inductances of the three inductors are M11, M22, and M33, and the mutual inductances are M12, M13, M21, M23, M31, and M32.Equivalent inductance is .Since the mutual inductance between any two inductors is equal to each other, the latter two sets of mutual inductance can be combined:Inductors in ParallelN ideal inductors without mutual inductance are connected in parallel. Similar to the method described above, the equivalent inductance Leq can be calculated as .Among them, Li is the inductance of the i-th inductor.The above equation describes an ideal case where n inductors are connected in parallel without mutual inductance.A parallel circuit composed of two inductors with inductances L1 and L2 and mutual inductance M:1) Assuming that the magnetic fields or fluxes generated by two inductors are in the same direction, the equivalent mutual inductance Leq is expressed by the equation: 2) Assuming that the magnetic fields or fluxes generated by two inductors are in opposite directions, Leq is expressed by the equation:For a parallel circuit with three or more inductors, it is necessary to consider the self-inductance of each inductor and the mutual inductance among the inductors, which makes the calculation more complicated. 👉 Switch in Series and Parallel Circuits2.4 SwitchSwitch in SeriesTwo or more switches are connected in series to form an or gate circuit. Assuming a power supply is connected to both ends of the circuit, current will only flow when all switches are closed.Switch in ParallelTwo or more switches are connected in parallel to form an or gate circuit. Assuming that a power supply is connected to both ends of this circuit, even though any one of the switches is closed, current will flow. 👉 Power Supply in Series and Parallel Circuits2.5 Power SupplyPower Supply in SeriesFor example, assuming that several cells in the battery pack are connected in series to form a power source, the voltage across the power source is the algebraic sum of the voltages across all cells.Power Supply in ParallelFor example, assuming that a battery pack uses several single batteries with the same voltage connected in parallel as a power source, the voltage across the power source is equal to the voltage across the single battery.Note: Get more info from Switching Power Supply Circuit Diagram with Explanation. 2.6 Series and Parallel Circuits RulesHow to judge whether the electrical circuits are connected in series or in parallel? Series and parallel are the two most basic forms of circuit connection, and there are certain differences between them. So get to know their basic characteristics well according to the following specific methods.(1) Visual CheckLook at the connection form of electrical parts in the circuit. The one by one in sequence is series; the one paralleled between two points of the circuit is parallel.(2) Current FlowWhen the current flowing from the positive pole of the power supply to each element in turn shows that the circuit is in series; when the current flows to two branches and get together at a certain place finally, it indicates that the circuit is in parallel.(3) Removing ComponentsRemove one electrical part at will to see whether other electrical components are working normally. If the circuit can continue to work, then the connection relationship of this circuit is in parallel, otherwise, it is in series. Ⅲ Six Circuit Design Software Tools Introduction3.1 Protel PCB Design PlatformProtel PCB is a CAD software for the circuit industry launched by Protel Systems Pty Ltd in 1985, and has rebranded to Altium Designer. It has many advantages compared with many EDA software for circuit designers. Almost all circuit companies use it. The early Protel PCB was mainly used as a printed board automatic wiring tool. It ran in DOS and had fewer hardware requirements. It can run under the 1M memory of a 286 machine without a hard disk. However, it’s less functional, only electrical schematic drawing and printed board design functions, and the PCB layout rate of automatic wiring is also low.It is a professional circuit board drawing tool. It includes electrical schematic drawing, analog circuit and digital circuit mixed signal simulation, multilayer PCB design, programmable logic device design, chart generation, circuit table generation, and supports macro operations, etc. And it has a client/server architecture. PROTEL is also compatible with some other design software file formats, such as ORCAD, PSPICE, EXCEL, etc. Using automatic routing of multi-layer can achieve 100% layout rate of high-density PCBs.3.2 Altium DesignerAltium Designer is one of the most popular of the high end PCB design software packages on the market today. It provides a single, unified application that incorporates all the technologies and capabilities necessary for complete electronic products, which mainly runs on the Windows operating system. This software provides designers with brand-new design solutions through the perfect integration of schematic design, circuit simulation, PCB drawing editing, topology logic automatic routing, signal integrity analysis and design output, etc. When using this software, the quality and efficiency of circuit design can be greatly improved.Fully inheriting the functions and advantages of the previous series of versions of Protel 99SE and Protel DXP, Altium Designer has many improvements and many high-end features. The platform broadens the traditional interface of board-level design and fully integrates FPGA design functions and SOPC design implementation functions, allowing engineers to integrate FPGA in system design with PCB design and embedded design. With these advantages, Altium Designer requires higher computer system performance than the previous version. 3.3 Quartus IIThe Altera Quartus II design software is a multiplatform design environment that easily adapts to your specific needs in all phases of FPGA and CPLD design. In other words, Quartus II software delivers the highest productivity and performance for Altera FPGAs, CPLDs, and HardCopy ASICs. It is a comprehensive CPLD/FPGA development software, and supports schematics, VHDL, VerilogHDL and AHDL (Altera Hardware supports Description Language) and other design input forms. Quartus II embedded with its own synthesizer and simulator, can complete the process of design input to the hardware configuration. It can run in Windows, Linux and Unix. Use Tcl scripts to complete the design process, and it also provides a complete user graphical interface design method. Quartus II has the characteristics of fast running speed, unified interface, centralized function, easy to learn and easy to use.Quartus II provides a fully integrated development which independent of circuit structure, with all the features of digital logic design, including:1. You can use the schematic diagram, structural block diagram, VerilogHDL, AHDL and VHDL to complete the circuit description, and save it as a design entity file.2. Chip (circuit) plane layout wiring editing3. With LogicLock region, users can build and optimize the system, and add subsequent modules that have little or no impact on the performance of the original system.4. Powerful logic synthesis tool5. Complete circuit function simulation and sequential logic simulation6. Timing analysis and critical path delay analysis7. Signaltap ii logic analyzer can be used for embedded logic analysis.8. Support the addition and creation of software source files, and link them to generate programming files.9. Use the combined compilation method to complete the overall design process at one time.10. Automatically locate compilation errors.11. Efficient period programming and verification12. Read into standard EDIF, VHDL and Verilog netlist files.13. It can generate VHDL and Verilog netlist files used by third-party EDA software.3.4 Electronics Workbench (EWB)EWB is is a mixed-mode SPICE-based electronics design and simulation tool, launched by Interactive Image Technology Co., Ltd. in the early 1990s. It is used for mixed simulation of analog circuits and digital circuits. With this powerful software, you can directly see the output of various circuits on the screen.Compared with other EDA software, EWB is a smaller software, and its function is relatively single. However. its simulation function is very powerful, almost 100% simulation results of real circuits. It provides parts such as multimeters, oscilloscopes, signal generators, frequency sweepers, logic analyzers, digital signal generators, logic converters, etc., and its device library contains many transistor components, integrated circuits and digital gate circuit chips from large companies.  In addition, components that are not in the device library can also be imported externally. Among many circuit simulation software, EWB is the easiest to use. Its working interface is very intuitive. The schematic diagram and various tools are in the same window. People who have never touched it can use the software proficiently with a short-time learning. For electronic designers, it is an excellent EDA tool. For many circuits, you can know its results without using a soldering iron. If you want to change components or change parameters, you only need to click the mouse. It can also be used as an auxiliary teaching software for electrical knowledge.3.5 NI MultisimMultisim is a Windows-based simulation tool launched by National Instruments (NI) Co., Ltd.. It is industry standard SPICE simulation and circuit design software for analog, digital, and power electronics in education and research. It includes graphical input of circuit schematics, circuit hardware description language input, and has rich simulation analysis capabilities. Engineers can use it to interactively build circuit schematics and simulate the circuit.With SPICE simulation, designers can quickly capture, simulate and analyze new designs without knowing SPICE deeply, which also makes it more suitable for electronics education. Through Multisim and virtual instrument technology, PCB designers and electronics educators can complete a complete integrated design process from theory to schematic capture and simulation to prototype design and testing.NI Multisim software is an EDA tool software specially used for electronic circuit simulation and design. As a personal desktop electronic design tool running in Windows, NI Multisim is a complete integrated design environment. Its computer simulation and virtual instrument technology can solve the problem of disconnection between theoretical teaching and actual reality experiment. Students can easily reproduce the theoretical knowledge they have learned through computer simulation, and can use virtual instrument technology to create their own instruments. It has an intuitive graphical interface, abundant components, powerful simulation capabilities, abundant testing instruments and complete analysis methods. NI Multisim software is a not bad teaching tool.3.6 Allegro PCBAllegro PCB is an advanced PCB design routing tool introduced by Cadence. It provides a good and interactive working interface, and powerful and complete functions. Provide the most perfect solution for the current high-speed, high-density, multi-layer complex PCB design and wiring, with the combination of its front-end products Cadence, OrCAD, and Capture. Allegro has a complete constraint setting. Users only need to set the wiring rules as required. The wiring design requirements can be met without violating DRC, thus saving tedious manual inspection time and improving work efficiency. It can also define parameters such as minimum line width or line length to meet the various requirements of today's high-speed circuit board wiring. Allegro PCB enables you to do high-speed design, RF antenna, flex-circuitry, and design for manufacturing (DFM) technology.For the drawing and modification functions of copper foil that the industry attaches great importance to, Allegro provides a simple and convenient inner layer division function, as well as the ability to review the inner layer of the positive and negative film. For copper paving, it can also be divided into dynamic copper or static copper, which can be used for different applications. Dynamic copper parameters can be divided into different levels of settings for all copper, single copper or single object, so as to meet the requirements of different connection effects or spacing values to match the special settings due to design requirements. Ⅳ Frequently Asked Questions about Series and Parallel Circuits1. What is the difference between parallel and series circuits?In a parallel circuit, the voltage across each of the components is the same, and the total current is the sum of the currents flowing through each component. ... In a series circuit, every device must function for the circuit to be complete. If one bulb burns out in a series circuit, the entire circuit is broken. 2. What are the rules for series and parallel circuits?Rules regarding Series and Parallel CircuitsVoltage drops add to equal total voltage.All components share the same (equal) current.Resistances add to equal total resistance. 3. What are the similarities and differences between series and parallel circuits?Series circuits are designed so that the current through each component is the same, whereas parallel circuits are designed so that the voltage through each component is the same. 4. Why is resistance different in series and parallel?In a series circuit, the output current of the first resistor flows into the input of the second resistor; therefore, the current is the same in each resistor. In a parallel circuit, all of the resistor leads on one side of the resistors are connected together and all the leads on the other side are connected together. 5. Which software is best for circuit design?Based on Proto-Electronics client preferences, we have drawn up the top 10 best electronics CAD software programmes.EagleAltiumProteusKiCadCadence OrCAD PCB DesignerDesignSparkProtelCadstar

The solid-state capacitor is called a solid-state aluminum electrolytic capacitor. The biggest difference between it and ordinary capacitors (i.e. liquid aluminum electrolytic capacitors) lies in the use of different dielectric materials. The dielectric materials of liquid aluminum capacitors are electrolyte, while the dielectric materials of solid capacitors are electroconductive polymer materials.   Electronic Basics #14: Capacitors Catalog I. Solid State Capacitor Introduction II. Solid State Capacitor Advantages III. Solid State Capacitor Types IV. Advantages and Disadvantages of Solid Capacitors FAQ   I. Solid State Capacitor Introduction   In view of the many problems of liquid electrolytic capacitance, the solid aluminum electrolytic capacitor has emerged as the times require. Since the 1990s, solid conducting polymer material has been used as cathode instead of electrolyte for aluminum electrolytic capacitor, which has achieved great development. The conductivity of conductive polymer materials is usually 2 ~ 3 orders of magnitude higher than that of electrolytes.    The application of aluminum electrolytic capacitors can greatly reduce the ESR and improve the features of temperature frequency, what’s more, because of the good processability of polymer materials, it is easy to be packaged. All greatly promote the development of aluminum electrolytic capacitance.   On the market, there are two types of aluminum electrolytic capacitors: organic semiconductor aluminum electrolytic capacitors (OS-CON) and polymer conductor aluminum electrolytic capacitors (PC-AC) (PC-CON).    The structure of an organic semiconductor aluminum electrolytic capacitor is similar to that of a liquid aluminum electrolytic capacitor; both are packaged in straight-pin and vertical configurations.   The difference is the cathode material of solid aluminum polymer electrolytic capacitor using the organic semiconductor extract, which can effectively solve the tough problems of electrolyte evaporation, leakage, flammability, and so on. Also, a solid aluminum polymer patch capacitor is a unique structure formed by combining the characteristics of aluminum electrolytic capacitance and tantalum capacitance.   Like liquid aluminum electrolytic capacitors, solid aluminum polymers are mostly in the form of patches. The film of polymer electrode with high conductivity is deposited on alumina as cathode, carbon, and silver as an extraction electrode, which is similar to the structure of solid tantalum electrolytic capacitance.     II. Solid State Capacitor Advantages   （1）With high stability, the solid aluminum electrolytic capacitor can work stably in a high-temperature environment, and improve the performance of the motherboard directly. At the same time, it is suitable for power filters because of its stable impedance in a wide temperature range, provides a stable and abundant power supply effectively, especially in overclocking.    Solid-state capacitors can work at high temperatures and maintain various electrical properties. The capacitance changes less than 15% in the whole temperature range, which is obviously superior to the liquid electrolytic capacitance. Meanwhile, the capacitance of solid-state electrolytic capacitor is independent of its working voltage, so it can work stably in the environment of voltage fluctuation.   （2）The solid-state aluminum electrolytic capacitor has an extremely long service life (over 50 years). It longer than the liquid aluminum electrolytic capacitance. And it will not be broken down, nor need to worry about liquid electrolyte drying and leakage affecting the stability of the motherboard. Solid-state electrolytes do not expand or even burn as liquid electrolytes do at high temperatures. Even if the temperature of the capacitor exceeds its limit, it just melts, which does not cause the capacitor metal shell to burst, so it is very safe.    The working temperature has a direct effect on the life of electrolytic capacitance. Advantages of its electrolyte make a longer service life than liquid electrolytic capacitor under different temperature conditions.   （3）Low ESR(Equivalent Series Resistance) and high mA rms are important indexes of capacitance. The lower the ESR, the faster the charge and discharge speed of capacitance. It directly affects the decoupling performance of the microprocessor power supply circuit, which is more obvious in high-frequency circuits. Therefore, it can be viewed the biggest difference between solid-state electrolytic capacitance and liquid capacitance.   Solid aluminum electrolytic capacitance with the lower ESR and energy dissipation under high power operation conditions can fully absorb the high amplitude voltage between the power lines in the circuit and prevent its interference to the system. When the CPU changes from a low power state to a full load state, the transient (generally less than 5 milliseconds) power required for this CPU switch comes from the CPU power supply circuit, at this moment, the high peak current can be output instantly by the high-speed charge-discharge characteristic of the solid-state capacitor, which can guarantee sufficient power supply and ensure the CPU to work stably.     III. Solid State Capacitor Types     According to the medium, capacitors can be divided into inorganic dielectric capacitors, organic dielectric capacitors, and electrolytic capacitors three categories.   1. Inorganic dielectric capacitors: including familiar ceramic capacitors and mica capacitors, we will often see ceramic capacitors on the CPU. Ceramic capacitors have excellent comprehensive properties and can be used in GHz-class UHF devices, such as CPU/GPU, thus its price is also very expensive.   2.Organic dielectric capacitors: such as thin-film capacitors, which are often used in loudspeakers with their precision, high temperature, and high-pressure resistance.   3. Electrolytic capacitors: known as aluminum capacitors. The traditional method of classifying electrolytic capacitors is based on anode materials, such as aluminum, tantalum, or niobium. However, this method of judging capacitance performance based on the anode is out of date. At present, the key to determine the performance of electrolytic capacitance lies not in the anode, but in the electrolytic, cathode. According to the classification of cathode materials, electrolytic capacitors can be divided into electrolyte, manganese dioxide, TCNQ organic semiconductors, solid polymer conductors, and so on.      IV. Breif Analysis of Advantages and Disadvantages of Solid Capacitors   The dielectric of liquid electrolytic capacitors is liquid electrolyte: liquid particles are very active at high temperatures and have a low boiling point relative to the internal pressure of the capacitor, making it easily explosible. The solid-state capacitance is made of polymer dielectric: at high temperatures, the particle growth and behavior of solid particles are lower than that of liquid electrolytes, and its boiling point will reach 350 degrees Celsius, making it almost impossible to burst.    The ESR of solid-state capacitance in high-frequency operation is shown to be very weak, and the conductivity is very fine. It has the properties of lowering impedance and producing less heat, which is the most obvious between 100KHz and 10MHz.   Traditional electrolytic capacitance is easily influenced by the operating environment's temperature and humidity, and it is less stable at high and low temperatures. The ESR of the solid capacitance can be as low as 0.0040.005 ohms between minus 55 and 105 degrees Celsius, but the electrolytic capacitance varies with temperature.   In terms of capacitance values, liquid capacitance would be lower than the indicated capacitance value below 20 degrees Celsius, and the lower the temperature, the lower the capacitance value. At minus 20 degrees Celsius, capacitance decreases by around 13%, and at minus 55 degrees Celsius, capacitance decreases by 37%. Since solid capacitance decreases by less than 5% at minus 55 degrees, solid state capacitors are guaranteed not to be harmed by lower temperatures. The low-frequency response of solid-state capacitance is not as good as electrolytic capacitance.     In other words, a motherboard with all-solid-state capacitance is not the most reasonable. Whether solid or electrolytic capacitors, their main function is to filter clutter, so long as the capacity and quality of capacitance can reach certain requirements, it can also ensure a stable operation. Solid-state capacitors at 105C have the same lifetime as electrolytic capacitors for 2000 hours.    When the temperature drops, their lives increase, but the solid-state capacitors increase even more. In general, the operational temperature of the capacitor is 70 degrees or less. In addition, the service life of solid-state capacitance can last 23 years, almost six times than the electrolytic capacitance. Compared with electrolytic capacitors, the capacity of electrolytic capacitors is much larger than that of solid capacitors at the same volume and voltage.     At present, solid capacitors are mostly used in the CPU power supply of computer motherboard, but the capacity redundancy is very little, it is necessary to improve the switching frequency of the part of the CPU power supply. Both solid and electrolytic capacitors will have the problem of capacity attenuation in the process of use. However, although the capacity of the circuit board with solid-state capacitance fluctuates slightly, the power supply will appear ripples, which will cause the CPU to work improperly.     Therefore, the lifetime of the solid-state capacitor is very high theoretically, but not in practice. Maintenance when using solid-state capacitor computer board: the power supply part of the CPU is often connected with multiple capacitors, so the solid-state capacitance will not have deformation, explosive slurry, leakage, etc. There is no way to determine which one is out of order basically. Therefore, in maintenance, one of them is often removed (no matter good or bad), and a large-capacity capacitor can be replaced (often with electrolytic capacitance). This method can usually solve the problem quickly.      In theory, the lifetime of the solid-state capacitor is very long, but there will still be a lot of faults in the process of practical use. At present, it seems that most motherboards with overclocking as the selling point put forward by many manufacturers will use solid-state capacitors. But it is not the capacitance that determines the performance of the CPU. The design of the circuit, the development of BIOS, the quality of the CPU itself, and the heat dissipation measures may determine the success or failure of the CPU.   FAQ   1. What is a solid state capacitor? The full name of a solid capacitor is a conductive polymer aluminum electrolytic capacitor, also called a polymer aluminum capacitor. It is currently the highest level of capacitor products. The dielectric material of the solid capacitor is a functional conductive polymer, which can greatly improve the product.   2. Are Solid Capacitors better? Solid capacitors have a higher tolerance not only for higher temperatures, but they also perform better with higher frequencies and higher current than electrolytic capacitors. ... Because there is less impedance at higher frequencies, solid capacitors are more stable and generate less heat than electrolytic capacitors.   3. How do you read a solid state capacitor? If you have a capacitor that has nothing other than a three-digit number printed on it, the third digit represents the number of zeros to add to the end of the first two digits. The resulting number is the capacitance in pF. For example, 101 represents 100 pF: the digits 10 followed by one additional zero.   4. What do you need to know about solid state capacitors? Solid-state capacitors have already gone down the altar. Many common electronic and digital products use these products in large quantities. The solid-state capacitors are similar to the common aluminum electrolytic capacitors, some are replaceable, and there is a solid capacitor, sheet, for Replace the common tantalum capacitor.   5. Which is the best electrolytic capacitor for motherboard? Solid aluminum electrolytic capacitors can directly improve the performance of the motherboard. At the same time, it is suitable for power supply filtering due to its stable impedance over a wide temperature range. It can effectively provide a stable and abundant power supply, which is especially important in overclocking.   6. How do you read a solid state capacitor? If you have a capacitor that has nothing other than a three-digit number printed on it, the third digit represents the number of zeros to add to the end of the first two digits. The resulting number is the capacitance in pF. For example, 101 represents 100 pF: the digits 10 followed by one additional zero.   7. What is the average lifespan of a capacitor? Design lifetime at rated temperature. Manufacturers of electrolytic capacitors specify the design lifetime at the maximum rated ambient temperature, usually 105°C. This design lifetime can vary from as little as 1,000 hours to 10,000 hours or more.   8. What metals are capacitors made of? There are three different anode metals in use for electrolytic capacitors: Aluminum electrolytic capacitors use a high-purity etched aluminium foil with aluminium oxide as dielectric. Tantalum electrolytic capacitors use a sintered pellet (“slug”) of high-purity tantalum powder with tantalum pentoxide as dielectric.   9. 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.   10. How do I choose the right size capacitor? You mainly need to look at 2 values: the voltage and the capacity -both are written on most capacitors-. For example, if you are going to charge a capacitor with 24V, you need to make sure your capacitor will support that voltage; so you'll need a capacitor for at least 25V (plus error margin).       You May Also Like Operational Amplifier(OP Amp) Tutorial Instructions of Common problems in the Application of Inverter About Operational Amplifier LM358: 24 Classical Circuits DIY Community:  DIY Capacitor Flux Capacitor - Back TO The Future

Ⅰ IntroductionThe vacuum tube was an essential part of early radios, used to create and amplify the electrical signals needed for the radio to work. The vacuum tube radio was a new stuff of the early 20th century, and immediately became the "new favorite" of that era with the launch of the radio show. Due to the continuous development of technology and the emergence of transistors, vacuum tubes were swept away by the powerful transistors in the 1960s and 1970s. With the improvement of people's lives, they have a new understanding of sound quality, and people are once again interested in the beautiful sound of vacuum tube radios.Vacuum Tube Radio RepairCatalogⅠ IntroductionⅡ Vacuum Tube Radio Circuit2.1 Input Circuit2.2 Converter Stage2.3 Detection Stage2.4 Intermediate Amplifier Stage2.5 Audio Voltage Amplifier2.6 Audio Power Amplifier Stage2.7 RectifierⅢ Classification3.1 AM Radio3.2 Heterodyne Radio3.3 FM Radio3.4 Service LifeⅣ Audio Maintenance PrincipleⅤ Specific Troubleshooting5.1 Tube Inspection5.2 Resistor Inspection5.3 Capacitor Inspection5.4 Transformer InspectionⅥ One Question Related to Vacuum Tube Radio and Going FurtherCompared with the semiconductor radio, the biggest advantage of the tube radio is that the sound quality is obviously better than that of the semiconductor radio. The second is that it is stable and elegant, with classical temperament. In addition, the history of tube radios is far greater than that of semiconductor radios, which are more valuable for collection. Ⅱ Vacuum Tube Radio CircuitFigure 1. 12AV6 Vacuum Tube Radio Circuit2.1 Input CircuitThe circuit from the antenna of the radio to the input of the first-stage tube is called the input circuit. It has two tasks to complete: One is to transmit the high-frequency signal voltage induced on the antenna to the grid of the first electron tube (usually the frequency conversion stage). To accomplish this task, there should be a certain coupling between the radio antenna and the input circuit to facilitate signal transmission. Second, because the antenna induces a lot of signals, it is necessary to select the radio broadcast signal you want to listen to  suppress unnecessary signals. To accomplish this task, the input circuit should be composed of a selective resonant circuit, so the input circuit should compose of coupling elements and the resonant circuit.Depending on the coupling form of the antenna and the resonance circuit. The input circuit can be divided into three types: inductive coupling (transformer coupling) circuit, capacitive coupling circuit, and inductive capacitive coupling circuit. Since the voltage transmission coefficient of the inductive coupling circuit is relatively high and uniform, tube radio usually adopts this type. In order to improve the suppressing ability of mid-frequency interference (because the intermediate-frequency detuning is smaller for medium wave, and it is larger for short wave.). An intermediate-frequency trap circuit is also applied in the antenna loop.2.2 Converter StageThe converter stage is located between the input circuit and the intermediate amplifier stage. Its function is to change the high-frequency amplitude modulation signal into a fixed intermediate-frequency amplitude modulation signal. In order to complete the task, the frequency converter should be composed of four parts: oscillator (generating a high frequency constant-amplitude oscillating voltage with an intermediate-frequency different from the frequency of the external radio signal), a high frequency circuit (used to select the radio signal, usually it is the input circuit), non-linear components (usually pentagrid converter, used to change the frequency), the intermediate-frequency loop.The converter stage of a tube radio is generally composed of a pentagrid converter tube. The high-frequency circuit is connected to the third grid (signal grid). The oscillator is composed of the screen grid (oscillation anode), the first grid (oscillation grid) and the cathode. The anode load is an intermediate frequency resonance circuit. Therefore, the main mark that distinguishes the converter stage from the tube amplifier is the pentagrid tube and three resonant circuits. The frequency converter can be divided into single-grid converter and double-grid converter according to the different ways of inputting signal voltage and local oscillation voltage. The single-grid inverter applies the signal voltage and the local oscillation voltage to the same electrode of the inverter tube, so the traction effect is large, and the operation is unstable. The double-gate inverter adds the signal voltage and the local oscillation voltage to the different electrodes of the inverter tube separately, the traction effect is greatly reduced, thus double-bar frequency converters are commonly used in tube radios.The structural feature of pentagrid tubes is that there are two metal sheets on the second grid, called the collection screen. It blocks the electrons moving to the anode. There are two metal rods on the third grid in the gap of the collecting screen, which carry negative potential. When the electrons passing through the second grid hit the negatively charged metal rod while advancing, the electrons flying to the anode is divided into two streams, one flying to the anode, and the other being collected by the collecting screen without returning to the cathode. In this way, when the signal grid voltage changes, it will only affect the distribution of the two currents, and has little effect on the total current. Because the local oscillator adopts the total current feedback, the oscillator is basically not affected, so the oscillation frequency is stable. There are many types of frequency converter circuits with different performances, but their principle difference lies in the way of local oscillation feedback. 2.3 Detection StageThe detection stage is located between the intermediate amplifier stage and the audio voltage amplifier stage. Its task is to transform the intermediate-frequency signal into the original modulated audio signal. To complete the task of frequency conversion, the detector must consist of an intermediate-frequency signal circuit (it is the output circuit of an intermediate-frequency amplifier), a non-linear elements (usually a diode), and a load (resistor). 2.4 Intermediate Amplifier StageThe intermediate amplifier stage is located between the frequency converter stage and the detection stage, and specifically amplifies the 465kHz intermediate-frequency signal. The main feature of the intermediate amplifier stage is: in order to achieve automatic gain control, the intermediate amplifier tube generally uses a remote cut-off tube. The intermediate-frequency transformer is the main component of the intermediate-frequency amplifier, and its quality directly affects the quality of the radio. In addition, a shielding cover is usually used to avoid the parasitic coupling between the intermediate-frequency loop and the eternal to improve the working stability. The shielding cover is made of good conductors such as aluminum and copper, and is attached to the case (ground potential), to isolate the entry of high frequency electromagnetic fields. 2.5 Audio Voltage AmplifierTo make the power amplifier stage output a certain amount of power, its anode current must have a certain amount of AC component, which requires that the grid audio signal voltage used to control the anode current must have a sufficiently large amplitude (voltage). The output voltage of the detector stage is usually very low. Therefore, between the power amplifier stage and the detector stage, there is always one or several audio voltage amplifier stages. Its function is to amplify the audio signal voltage to meet the input signal requirements.The audio voltage amplifier stage can be divided into a resistance-capacitance coupling amplifier and a transformer-coupled amplifier according to the different anode load forms. In the vacuum tube radio, the resistance-capacitance coupling amplifier is used mostly. The audio voltage amplifier stage and the detection stage usually share an electron tube. The input signal is generally controlled by a volume control potentiometer to adapt to different broadcasts and listening situations. Some radios have a tone control circuit connected to the output end of the audio voltage amplifier stage to flexibly change the frequency characteristics of the amplifier to make the sound pleasant. Due to the different forms of volume and tone control circuits. There are many types of audio voltage amplifier stages. 2.6 Audio Power Amplifier StageThe audio power amplifier stage is the last stage of the tube radio, and its function is to output a certain amount of audio power to make the speaker work normally. Someone may wonder, can a voltage amplifier be used instead of a power amplifier? This will not work. Although there is no difference between the basic circuits of a power amplifier and a voltage amplifier, due to the different tasks of the two, there are significant differences in the selection of electron tubes, the circuit components, and the nature of the load. It should be pointed out that the so-called power amplifier does not amplify the input power itself, but uses the control function of the electron tube grid voltage to convert the power supplied by the anode circuit DC power supply into the required audio power. From the viewpoint of energy conversion, the power amplifier is an energy converter. 2.7 RectifierThe rectifier stage of the tube radio is composed of three parts: power transformer, rectifier tube and filter. There are many forms of rectifier circuits, and the most common is a full-wave rectifier circuit.Ⅲ Classification3.1 AM RadioIn the era when tube radios were popular. AM radios were the mainstream products. Amplitude modulation is to modulate the high frequency carrier with audio signal. Its waveform is symmetrical up and down, and the amplitude is the same as the modulated signal. After detection, the highfrequency component is filtered out to obtain the audio signal. 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. The sound quality is affected, and electromagnetic interference is relatively large.There are two main types of AM radios: direct-amplifier type and heterodyne type.1)Direct-amplified radio, also known as high-amplification radio, its typical circuit structure is such as: High-amplification→Detection→Low-amplification→Power amplifierA circuit that uses a grid detector circuit and a high-frequency positive feedback, called a regenerative radio, can achieve better sensitivity and selectivity. It can receive AM telegraph signals with high-amplifier and short-wave. Old Japanese-made radios mostly have this circuit. High-frequency signals of direct-amp radios are prone to self-excitation, and the high-end and low-end gains are uneven, and there is no high-amplifier regeneration. Widespread use of reed speakers with poor sound quality made it obsolete. Out of nostalgia, some enthusiasts are still keen on getting recycled radios. The regenerative circuit can not only be applied to direct-amplified radios, but also in simple heterodyne radios, because proper positive feedback can also be used to improve sensitivity.Simple regenerative radios often use reed speakers, which have high impedance (about 10K) and high sensitivity, and can be directly used as the load of the power amplifier tube. Its frequency range is only 350~3000Hz, so the sound quality is poor. Later regenerative radios used moving coil speakers, and the sound quality was better. However, due to the low impedance, an output transformer is needed, and its primary impedance must match the load impedance of the power amplifier tube. Moving coil speakers are divided into permanent magnet, constant magnet and excitation type. In addition, excitation horns are used in AC tube radios, and their excitation coils can also be used as filter chokes. 3.2 Heterodyne RadioThe heterodyne radio uses a frequency conversion circuit. The signal generated by the high-frequency oscillation circuit is different from the input signal at a certain frequency. After the two are combined, a fixed intermediate frequency signal (455~465KHz) is generated. The oscillation circuit needs independent vacuum tube as a part before the emergence of the dedicated frequency conversion tube. Some people call the oscillation frequency higher than the signal frequency by a heterodyne type.Heterodyne plus intermediate-frequency amplifier circuit is called superheterodyne. This type of circuit requires a single electron tube to oscillate. Later a multi-pole or composite tube dedicated to frequency conversion appears, such as 1A2, 6A2, 6SA7GT, 6U1, 6K8, etc. The superheterodyne type is the most common circuit of commercial radios. It has an automatic volume control circuit and can add tuning instructions. The superheterodyne radio can obtain more stable and higher gain due to the fixed frequency amplified. The disadvantage is that there is image frequency interference.The circuit structure of a typical superheterodyne radio is as follows:Frequency conversion→Middle amplifier→Detection→Low amplifier→Power amplifier 3.3 FM RadioFM is to use audio signal to modulate the frequency of high-frequency carrier. Its advantages are strong anti-interference ability, high signal-to-noise ratio, good frequency bandwidth and sound quality, and the audio frequency can reach 20~15000Hz. Because the FM audio work in the ultra-high frequency band, it can accommodate many radio stations. Because of 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 (in the early days of stereo broadcasting, two frequencies were used and received by two radios). Amateurs like to use a simple super-regenerative circuit to receive FM broadcasts. Because it works in a self-oscillation state, it is unstable and has strong super noise. 3.4 Service LifeThe general design life of the valves is 2000 hours (special tube has 5000~10000 hours), but in reality, many electron tubes break after using 2000 hours, for example, there is no sound. Its performance is not up to the design standard. When there is not any sound from the actual tube, it may have reached 3000 hours or more. The actual service life of the amplifier tube of the front stage is longer. To cite the simplest example: the old picture tube (picture tube is also a kind of vacuum tube) of a TV set, the actual life span usually excesses 10 years.If use it for 5 hours a day, you need to change the tube once a year to meet the actual design performance, and the replaced tube can also be used for other purposes.Ⅳ Audio Maintenance PrincipleHow to repair the failure of the vacuum tube radio depends on the difficulty of the failure. Under normal circumstances, the following steps are used.First point is to seek clues. What is the difference in the use of the radio before and after the failure, thinking about whether it has been repaired, or what components have been replaced, etc.Second point is the fault display. For faults such as flashover, smoking, burning, etc. Turn off the power immediately and find the factor to avoid damage to the audio. According to the displayed failure phenomenon, rotate audio button to compress the failure to clarify where the failure may occur, and to provide necessary information for analysis and judgment.Third point is analysis and judgment. Make comprehensive analysis and judgment based on the information obtained by self-examination inference and fault display. List all possible direct causes of the failure, and develop a scientific inspection procedure. This not only prevents blind movement, but also accumulates maintenance experience and improves efficiency.Fourth point is troubleshooting. Gradually narrow the scope of the fault, and accurately detect the fault point. Sometimes it refers to (such as electron tubes, capacitors, resistors, coils, transformers, etc.) connecting wires, welding points of a certain component. Determine where the failure occurred, which is important for fault repair. Tube radios are usually divided into high-frequency part, intermediate frequency part, audio part, power supply part and auxiliary circuit according to their working frequency and circuit function. The fault should be compressed to a specific circuit, such as DC circuit, AC circuit, or the anode circuit, the screen grid circuit, grid circuit, cathode circuit, etc. Since each loop in the electronic tube circuit affects each other, a failure of a component may affect several loops at the same time. Therefore, in the inspection process, comprehensive analysis should be performed, that is, each circuit should not be isolated.Fifth point is repairing practice. The repair test can be performed after determining the cause of the failure.Sixth point is repair inspection. In the actual maintenance process, if a failure point is detected, it must be immediately eliminated and repaired. After all the faults are investigated, the radio should be inspected as necessary to ensure the quality of the repair. The specific content of the inspection depends on the specific fault and the type and quantity of the instrument. The simplest one should also be auditioned and take general technical observations.Ⅴ Specific TroubleshootingA radio is composed of many components, and component damage is the main cause of radio failure. When the fault location is gradually reduced, the quality of the components must be checked to determine the fault. Therefore, inspecting components is one of the main methods to find the cause of failure.5.1 Tube InspectionThe common faults of electronic tubes are mostly filament broken, poor contact of the electric board, broken pole, pole touching, leakage, breakdown between the cathode and the filament, aging, air leakage, and micro-sound effects. When the radio is turned on, if the filament of a certain tube does not light up, the filament may be broken or a serious leak. The tube shell is cold when the filament is broken, and the tube shell is often warm when the gas leaks. Unplug the tube for further inspection. Use a multimeter to measure the filament resistance at the "R×1"gear. If the meter indicates infinite, the filament is disconnected. If the indicator of the needle is zero, it means that the tube is short-circuit. When the indicator of the needle indicates a constant value, it means that there is leakage between the electrodes. The smaller the resistance, the more serious the leakage. At this time, the top of the tube is usually milky white.The electron tube electrode is in poor contact, intermittently electrode touching (some are hot electrode touching), and the radio will sometimes have no sound or noise. This type of failure is characterized by being greatly affected by vibration. Therefore, you can tap the tube shell lightly. If there is no sound or noisy sound (sometimes there may be no sound or normal sound after tapping), it means that the tube electrode is in poor contact or intermittently electrode touching. When the fault is serious, the electrode is completely disconnected, which means a broken pole. The tube does not work, and the radio is silent.When the electron tube ages, the positive current and the amplification will decrease. If it was frequency conversion tube, the local oscillator will oscillate abnormally, resulting in the radio cannot receive the radio signal, low sound, or the high frequency end of the band can receive one or two radio stations, and the low-frequency end cannot receive the radio signal. The micro-phonic effect of the vacuum tube is often caused by improperly fixing the electrode, and it can be judged by tapping the tube case lightly. Sometimes it is difficult to determine whether the valve is normal or not. The easiest way is to replace it with the same type of electron tube. If the failure disappears, it means that there is a problem with the vacuum tube. 5.2 Resistor InspectionThere are two types of resistors used in radios: fixed resistors and variable resistors (potentiometers). They are not easy to damage. Possible damages include: resistor burnout, resistor body broken or lead broken, internal open circuit, or poor lead contact, etc. Some of failure can be observed. For example, the increase of fault current in a certain part of the circuit, which means the resistor is burned out. At this time, the paint layer on the outside of the resistor is burnt and hot. If the resistor is internally disconnected or the resistance value changes, it can be checked by measuring the ohm gear of a multimeter. If the meter indicates infinity, it means that the resistor is internally open; if the measurement result is too far from the nominal value (the error exceeds 20%), it means that the resistance has deteriorated.The lead of the resistor body is in poor contact and will be broken unbroken, which will cause noise or sound from the radio. This kind of failure is very susceptible to vibration and produces vibration noise. Therefore, you can gently shake the resistor body to see if the sound changes. It can also be measured with a multimeter. When measuring, shake the resistor body. If the pointer is unstable, it means that the contact is bad.The potentiometer that controls the volume of the radio usually has a power switch. The common faults of the potentiometer are: dirty carbon film, wear of the carbon film, poor contact of the sliding contact, loose lead-out piece, burnt of the carbon film, broken bakelite frame of the sliding contact, leakage, and damage to the power switch. When the potentiometer is normal, the radio can only hear a very light sound after power on. If the potentiometer is closed, the broadcast voice should not be heard. After turning off the power, there is no sound. If you cannot control the power on and off, it indicates that the power switch is partially damaged; if the noise is very loud, especially when the volume is adjusted, the loudspeaker has a large sound or interrupted sound, it means that the potentiometer is in poor contact. 5.3 Capacitor InspectionThere are two types of capacitors used in radios: fixed capacitors and variable (semi-variable) capacitors. The faults of fixed capacitors are usually leakage, breakdown, internal open circuit, poor internal contact, broken lead, or capacity failure, etc. The common faults of variable capacitors are bump, short circuit, leakage and so on. 5.4 Transformer InspectionCommon faults in transformers are coil mold breakage, a partial short circuit, leakage and other faults. A multimeter can also check out the coil mold. When high-frequency coils and intermediate-frequency transformers are locally short-circuited, it is not easy to measure. The substitution method can be employed to test or adjust the loop frequency to figure problems out.Ⅵ One Question Related to Vacuum Tube Radio and Going Further6.1 QuestionWhy do vacuum tubes sound better?6.2 AnswerTubes sound better because their distortion products are more musical. Those are the fundamental reasons why tubes simply sound better. Vacuum tubes are the more linear and require less feedback. Tubes are voltage amplifiers as opposed to transistors which are current amplification devices. Frequently Asked Questions about Vacuum Tube Radio1. What is a vacuum tube radio?VACUUM TUBE RADIO. Vacuum Tube Radio. 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. 2. How do radio vacuum tubes 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. ... When the cathode is heated, and a positive voltage is applied to the anode, electrons can flow from the cathode to the anode. 3. Why are vacuum tubes better for audio?Tube amplifiers sound better because of the euphonic distortions they add to the music, as well as plenty of other reasons I'll cover below. ... We use tubes simply because they make the music we create sound better: smoother, warmer and cleaner. Ditto for guitar amplifiers used in creating music. 4. How do you know if a vacuum tube is bad?When a vacuum tube develops an air leak (a small crack or bad seal by a pin for example) this getter color will change to pure white. If you see this you know with 100% certainty that the tube is bad. Third, look for a purple glow that is very focused around specific elements inside the tube.