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CatalogCatalogⅠ Oscillation DefinitionⅡ Definition of Voltage Controlled OscillatorⅢ Types of Voltage Controlled Oscillator  3.1 Harmonic Oscillators  3.2 Relaxation OscillatorsⅣ Working Principle of Voltage Controlled OscillatorⅤ Voltage Controlled Oscillator Requirements  5.1 VCO tuning range  5.2 VCO tuning gain  5.3 VCO V/f slopeⅥ Voltage Controlled Oscillator FeedbackⅦ Colpitts & Clapp Voltage Controlled Oscillator CircuitsⅧ Voltage Controlled Oscillator Varactor Issues  8.1 Abrupt  8.2 Hyper-abruptⅨ FAQⅠ Oscillation DefinitionAn oscillator is a circuit that, without any input, generates a continuous, repeated, alternating waveform. Basically, oscillators transform unidirectional current flow from a DC source into an alternating waveform that, as determined by its circuit components, is of the desired frequency. By observing the behavior of the LC tank circuit shown in Figure 1 below, which uses an inductor L and a completely pre-charged capacitor C as its components, the basic theory behind the operation of oscillators can be understood. In this case, the capacitor initially begins discharging through the inductor, which results in the conversion of its electrical energy into an electromagnetic field that can be stored in the inductor. There will be no current flow in the circuit until the capacitor discharges fully.The stored electromagnetic field, however, would have created a back-emf by then, which results in the flow of current through the circuit in the same direction as before. This flow of current through the circuit continues until the electromagnetic field collapses, resulting in the electromagnetic energy back-conversion into electrical form, allowing the cycle to repeat. Now, however, the capacitor would have been charged with the opposite polarity, because of which an oscillating waveform is obtained as the output. However, because of the resistance of the circuit, the oscillations that occur due to the inter-conversion between the two energy-forms will not continue indefinitely as they will be subject to the impact of energy loss. The amplitude of these oscillations gradually decreases to zero as a result, making them damp. This means that the energy loss needs to be balanced to achieve continuous oscillations and constant amplitude. However, in order to achieve oscillations of constant amplitude, it should be noted that the energy supplied should be precisely regulated and must be equal to that of the energy lost.Ⅱ Definition of Voltage Controlled OscillatorA voltage-controlled oscillator (VCO) is an output signal oscillator whose output can be varied over a particular frequency range that is controlled by the DC voltage input. It is an oscillator whose output frequency is directly connected by its input to the voltage applied (FM control).A main parameter of the VCO is the sweeping time: this is the minimum time required to turn or sweep from minimum frequency to maximum frequency or reverse. From an external analog signal, the VCO can be modulated by amplitude (AM). To produce the requested RF power level, an external power amplifier may be required.Ⅲ Types of Voltage Controlled OscillatorThe VCOs can be categorized based on the output waveform:• Harmonic Oscillators• Relaxation Oscillators3.1 Harmonic OscillatorsThe output waveform that harmonic oscillators generate is sinusoidal. This can also apply to the oscillator that regulates the linear voltage. The LC and Crystal oscillators are examples. Here, the capacitance of the diode varies according to the voltage around the diode. This in turn alters the LC circuit's capacitance. Hence, the frequency of the output will change. The advantages are frequency stability in terms of power supply, noise and temperature, and frequency control precision. The only downside is that this form of the oscillator on monolithic ICs can not be implemented effortlessly.3.2 Relaxation OscillatorsThe waveform output produced by harmonic oscillators is a screwed tooth. Using the decreased amount of components, this type may provide a wide range of frequency. It can primarily be used in ICs that are monolithic. The oscillators for relaxation may have the following topologies: • Delay-based ring VCOs • Grounded capacitor VCOs • Emitter-coupled VCOs Here: In delay-based ring VCOs, in a ring shape, the gain stages are connected. As the name implies, in every single point, the frequency is connected to the delay. The VCOs of the second and third types act almost equally. The time taken in each stage is directly linked to the capacitor's charging and discharging time.Ⅳ Working Principle of Voltage Controlled Oscillator Using several voltage regulation electronic components such as varactor diodes, transistors, Op-amps, etc., VCO circuits can be built Here, using Op-amps, we are going to address the function of a VCO. Below, the circuit diagram is shown.A square wave is going to be the output waveform of this VCO. The output frequency is, as we know, connected to the control voltage. The first Op-amp will act as an integrator inside this circuit. The arrangement of the voltage divider is applied here. Because of this, half of the control voltage given as input is supplied to the Op-amp 1 positive terminal. At the negative terminal, the same voltage level is retained. This is to maintain the voltage drop, R1 as half of the control voltage, across the resistor. The current flowing from the R1 resistor passes through the MOSFET when the MOSFET is in good condition. The R2 has half of the resistance, the same drop in voltage and twice the current as of the R1's. So, the attached capacitor is charged by the extra current. To supply this current, the Op-amp 1 should have a gradually increasing output voltage. The current flowing from the R1 resistor passes through the capacitor and gets discharged when the MOSFET is out of order. The output voltage obtained at this time from the Op-amp 1 will decrease. A triangular waveform is therefore produced as the output of Op-amp 1. The Op-amp 2 will act as a catalyst for Schmitt. A triangular wave that is the output of the Op-amp 1 is the input to this Op-amp. If the input voltage is greater than the threshold level, VCC will be the output from the Op-amp 2. If the input voltage is lower than the threshold level, the Op-amp 2 output is zero. The output of the Op-amp 2 is therefore going to be square waves. LM566 IC or IC 566 is an instance of VCO. In fact, it is an integrated 8-pin circuit that can generate double-square wave and triangular wave outputs. Below, the internal circuit is depicted.Ⅴ Voltage Controlled Oscillator RequirementsThere are several parameters that must be considered before the design begins when designing a voltage-regulated oscillator, VCO. These describe the parameters of key performance required for the VCO. 5.1 VCO tuning rangeIt is clear that the oscillator that is powered by voltage must be able to tune over the range that the loop is supposed to work over. This requirement is not always simple to satisfy and, in certain extreme situations, can require the VCO or resonant circuit to be switched. 5.2 VCO tuning gainThe gain of the oscillator regulated by voltage is important. It is calculated per Hz (or V/MHz, etc) in terms of volts. It is the tuning shift for a given change in voltage, as indicated by the units. Any of the overall loop design factors and measurements are influenced by the voltage-controlled oscillator gain.At lower frequencies, the VCO response curves can be shown to be relatively straight. They typically flatten out at higher voltages, however, where the capacitance changes from the variable diodes decrease. 5.3 VCO V/f slopeFor any voltage-driven oscillator used in a phase-locked loop, it is a crucial requirement that the voltage to frequency curve is monotonic, i.e. it always shifts in the same context, usually increasing voltage frequency. If ti alters, as can generally occur in some instances due to spurious resonances, etc., this can cause the loop to become unstable. This must therefore be avoided if the phase-locked loop is to work satisfactorily. This curve shows a slight dip which will result in an unstable phase-locked loop.Phase noise efficiency: In some PLL applications, the phase noise performance of the voltage regulated oscillator is of particular importance - particularly where it is used in frequency synthesizers. Outside of the PLL loop bandwidth, the phase noise output of the voltage-regulated oscillator is the dominant factor in phase noise. While the operation of the PLL reduces close-in noise, there is no reduction in VCO phase noise outside the loop bandwidth. These are some of the main specifications that must be understood from the outset of the VCO design. Careful optimization of the tuned circuit Q, especially the use of variable diodes with as high a Q as possible, selection of the active system, optimization of the oscillator feedback.Ⅵ Voltage Controlled Oscillator FeedbackA VCO can be considered, like any oscillator, as an amplifier and a feedback loop. It is possible to denote the amplifier's gain as A and the feedback as B. For the circuit to oscillate, 360 ° must be the complete phase shift around the loop and unity must be the gain. Signals are fed back around the loop in this manner so that they are addictive and, as a result, any slight disturbance in the loop is fed back and builds up. Because the feedback network is frequency-dependent, the signal is based on one frequency, the feedback network is resonant, and a single frequency signal is produced. A typical emitter circuit is used by many oscillators and thus by VCOs. This in itself generates a 180° phase shift, leaving a further 180° to be given by the feedback network. A typical base circuit where there is no phase shift between the emitter and collector signals (assuming a bipolar transistor is used) can be used by other oscillator or VCO circuits and the phase shift network must provide either 0 ° or 360 °. The device requires a resonant circuit for the oscillator to oscillate on a given frequency to ensure that the oscillation happens on a given frequency. The resonant circuit may be one of a variety of LC resonant circuit configurations, depending on the circuit, or a quartz crystal, etc., in either series or parallel resonance.Ⅶ Colpitts & Clapp Voltage Controlled Oscillator CircuitsThe Colpitts and Clapp oscillator circuits are two commonly used formats for the VCO. Of the two, the most commonly used is the Colpitts circuit, but both are somewhat similar in their configuration. These circuits serve as oscillators because an active device such as a bipolar transistor with capacitors positioned between the base and the emitter (C1) and the emitter and the ground (C2) has been found to fulfill the requirements needed to provide adequate feedback for the output of the oscillator in the correct step. The C1:C2 ratio must be greater than one for the oscillation to take place. The resonant circuit is rendered between the base and ground by adding an inductive function. This consists of only an inductor in the Colpitts circuit, while an inductor and capacitor in series are used in the Clapp circuit.The resonance conditions are that:The capacitance for the overall resonant circuit consists of a series of combinations of the two C1 and C2 series capacitors. The capacitor in the series with the inductor is also used in the series with C1 and C2 in the case of the Clapp oscillator.The capacitance of the series is thus:It is important to change the resonant point of the circuit to make the oscillator tune. This is better accomplished in the case of the Colpitts oscillator, by inserting a capacitor across the indicator. Alternatively, the capacitor may be in series with the inductor for the Clapp oscillator. A circuit where the inductive reactance is located between the base and ground is often favored for high-frequency applications because it is less vulnerable to spurious oscillations and other anomalies.Ⅷ Voltage Controlled Oscillator Varactor IssuesIn order to ensure that the drive frequency in the tuned circuit is not too high, caution must be taken in the design of the circuit when varactor diodes are used inside a voltage-driven oscillator. If this is the case, then the varactor diodes, reducing the Q and increasing the number of spurious signals, can be forced into forwarding conduction. Within a VCO, there are two main types of varactor diode that can be used-the name refers to the diode junction and this impacts their output.8.1 Abrupt: Abrupt diodes have a relatively sharp transition between the areas of the diode, as the name implies. They are able to give a higher Q than their hyper-abrupt relatives, while abrupt varactor diodes do not offer such a high tuning range or linear transfer characteristic. This results in a better oscillator phase noise output regulated by voltage. The other point to note is that in order to have the appropriate tuning range, abrupt varactor diodes may need a high tuning voltage, as certain diodes may need a tuning voltage for the VCO to differ up to 50 volts or slightly more. This can cause problems with supplying the drive circuits with a voltage supply with a sufficiently high voltage.8.2 Hyper-abrupt: There is a relatively linear voltage for hyper-abrupt diodes: the capacitance curve. As a consequence, in some applications, they give a very linear tuning characteristic that may be needed. They can also tune over a wide range, and can normally tune over an octave range with less than a 20-volt tuning voltage shift. They do not give an especially high Q standard, however. Since this will deduct from the tuned circuit's overall Q, this will mean that the output of the phase noise is as good as that which can be obtained using an abrupt varactor diode. Despite the apparent simplicity of the circuit, the voltage-controlled oscillator design is far from trivial. A design would also involve careful optimization of the levels of input coupled with the system and layout. The VCO's design will need to carefully balance the requirements of sometimes conflicting requirements, such as a large tuning range and low noise phase. The standards of efficiency that can be achieved are surprisingly good once the design has been completely configured and the design has been completed.Ⅸ FAQ1. What is a Voltage Controlled Oscillator?A voltage-controlled oscillator (VCO) is an electronic oscillator whose oscillation frequency is controlled by a voltage input. The applied input voltage determines the instantaneous oscillation frequency. 2. What is the use of VCO in PLL?VCO stands for Voltage Controlled Oscillator. PLL operation is simple. VCO creates a high-frequency clock that is divided by some factor. This divided frequency is compared against a stable, reference, frequency using a phase comparator and difference (in-phase or frequency) is converted into voltage and fed back into VCO.Depending on voltage difference VCO frequency will be higher or lower.For example, let’s suppose we have VCO generating 10000 at 5V and divide by 100 dividers. The reference frequency is 90. The phase comparator will subtract two frequencies, 100 - 90 = 10 and will produce some voltage proportional to the frequency difference. This voltage is fed back into VCO and will increase 5V to 6V. Voltage increase will result in frequency drop. The process will continue as long as VCO generated frequency is equal to reference, in our case 9000.From above we see PLL output frequency is: Out = Ref * DividerVCO in RF is produced using varicap diodes - diodes which capacity depends on reverse voltage. Varicap diodes are available with capacities ranging from 1pF up to 500pF and capacity change 2 - 20. How PLL is stable depends on the reference clock and a phase comparator. In the simplest case phase comparator are the XOR gate and RC filter. 3. Why is VCO better than DCO?Of course, the real answer depends on the application. But one important application for a VCO is to implement a so-called phase-lock-loop. In that application, the smoothly continuous frequency vs voltage characteristic of a VCO would allow the VCO to track some variable reference frequency much more precisely. A 'typical' DCO in the same application could only achieve a step-wise approximation to tight tracking. Another, historically more important, application of a VCO is as the primary component of an FM broadcast transmitter. Using a conventional DCO in this application would typically produce an unacceptable amount of weird, noisy distortion in the demodulated audio as the DCO control input attempted to track the audio signal. But yes, it is possible to conceptualize, and even practical to design, a DCO whose frequency control steps are so fine and rapid that, used in an FM broadcast transmitter, the listener would not notice the step-wise tuning of the carrier. 4. What is the function of a VCO voltage-controlled oscillator?A voltage-controlled oscillator (VCO) is an electronic oscillator whose oscillation frequency is controlled by a voltage input. The applied input voltage determines the instantaneous oscillation frequency. 5. How does voltage control oscillator work?A voltage-controlled oscillator is an oscillator with an output signal whose output can be varied over a range, which is controlled by the input DC voltage. It is an oscillator whose output frequency is directly related to the voltage at its input. The oscillation frequency varies from few hertz to hundreds of GHz. 6. How do you make a voltage-controlled oscillator?To make a VCO, the oscillator needs to be tuned by a voltage. This can be achieved by making the variable capacitor from varactor diodes. The tuning voltage for the VCO can then be applied to the varactors. 7. What is the output of VCO?The VCO has an output power level of -3 dBm into 50 Ω with phase noise of -101 dBc/Hz typical at 100 kHz offset. The control voltage range is 0.4 to 2.4 volts, and load pulling is typically 0.75 MHz, pk-pk. Power supply pushing is 280 kHz/volt (typical). 8. What is the VCO tuning range?The VCO is linearly tunable from 806 to 1,113 MHz with a 34% tuning range controlled linearly by the tuning voltage. The phase noise of the VCO is -100.4 dBc/Hz at 100-kHz offset frequency from a 903 MHz carrier. 9. What is VCO phase noise?Characterizing Phase Noise. The term phase noise is widely used for describing short-term random frequency fluctuations of a. signal. Frequency stability is a measure of the degree to which an oscillator maintains the same value. 10. Which is the input terminal in a VCO?It generates the square wave at the output whose frequency is determined by a control voltage. The first op-amp works as an integrator. The control voltage is applied at the input terminal and due to the voltage divider arrangement, half the control voltage is applied at the positive terminal of the first op-amp. 

Introduction: A Comprehensive Guide to Using a Multimeter in 2025When it comes to measuring instruments, the question often arises: how do you use a multimeter effectively? A Multimeter, also known as a VOM (volt-ohm-milliammeter) or DMM (Digital Multimeter), is the indispensable "Swiss Army Knife" for electronics. It is used to measure two or more electrical values—principally voltage (volts), current (amps), and resistance (ohms) in electronic and electrical circuits.In 2025, modern multimeters have evolved significantly. Beyond basic measurements, many now include features like capacitance testing, transistor checks, temperature sensing, and even Bluetooth connectivity for smartphone data logging. Whether you are troubleshooting a smart home device, checking automotive wiring, or testing a battery, the multimeter is your primary diagnostic tool.Multimeters are generally divided into two types: analog multimeters and digital multimeters (DMM). While analog meters use a moving needle, digital versions are now the industry standard, offering high accuracy, auto-ranging capabilities, and easy-to-read LCD or OLED displays. This guide is designed for beginners and will cover the basic parts, working principles, functions, and safety tips for using a multimeter in the modern era.Ⅰ What are the Parts of a Multimeter?The anatomy of a multitester generally includes a display (scale or screen), a selection knob, ports (jacks), and test probes. However, the interface differs between the older analog style and modern digital tools.Analog Multimeters: Use a microammeter with a moving pointer (needle) to display readings against a printed scale. They require the user to interpret the scale based on the selected range.Digital Multimeters (DMM): The current mainstream choice. They feature a numeric digital display, often with a backlight for dark environments. Modern DMMs may also include "True RMS" for accurate AC readings and auto-ranging features that automatically select the correct measurement scale for you.A common digital multimeter is composed of three main interface parts:1.1 The Display (Meter Head)On a digital multimeter, this is the LCD or LED screen where measurement values are shown. It often displays icons for battery life, high voltage warnings, and the unit of measurement (e.g., V, A, Ω). High-end models in 2025 may feature high-resolution color screens or bar graphs that mimic analog needles to show fluctuating signals.1.2 Measuring Circuit (Internal)Hidden inside the case, the measuring circuit converts incoming analog signals (voltage, current, resistance) into digital data. It is composed of precision resistors, an Analog-to-Digital (A/D) converter, and protective fuses to ensure safety during overload.1.3 Rotary SwitchThe central dial allows you to select the function (Volts, Amps, Ohms) and the range. In Auto-ranging multimeters, you simply select the function (e.g., DC Voltage), and the meter automatically adjusts to the scale of the signal. In Manual-ranging meters, you must select the specific range (e.g., 20V, 200V) yourself.Ⅱ Working Principle of MultimeterA Digital Multimeter (DMM) works by converting an analog input signal into a digital value using an A/D converter. The core logic involves comparing the input voltage against a reference voltage.To measure current and resistance, the multimeter actually uses voltage as the base reference:Current: The meter measures the voltage drop across a known internal shunt resistor.Resistance: The meter outputs a small, known current through the component being tested and measures the resulting voltage to calculate resistance (Ohm's Law).Modern DMMs use complex logic control circuits to manage the display, auto-ranging, and safety checks, ensuring that the reading on the screen is stable and accurate. Ⅲ Multimeter Operating ProceduresTo ensure accuracy and safety—especially with modern high-energy circuits—follow these steps:Safety Check: Inspect your test leads for damaged insulation. Ensure the multimeter is rated for the voltage you are testing (e.g., CAT III or CAT IV ratings for household mains).Select Function: Turn the rotary dial to the correct setting (Voltage, Current, or Resistance) before connecting the probes.Select Range: If using a manual-ranging meter and the value is unknown, always start at the maximum range and switch down to lower ranges to get a precise reading. Auto-ranging meters handle this automatically.Zero Calibration: For resistance measurements on analog meters, touch the probes together and zero the needle. Digital meters usually auto-zero, but you can check the "Rel" (Relative) mode on advanced models to null out lead resistance.Power Off for Resistance: Never measure resistance or continuity on a live circuit. Turn off the power to the device before testing.Probe Handling: Keep your fingers behind the finger guards on the test probes to avoid electric shock.Ⅳ Common Multimeter FunctionsMeasure Resistance (Ohms - Ω)Ensure the circuit power is OFF. Connect the test leads across the component (resistor, coil, etc.). Note: Measuring a component while it is soldered to a PCB may give inaccurate results due to parallel paths from other components.Measure Current (Amps - A/mA)Critical Step: You must physically move the red probe to the specific "Amps" or "mA" jack on the multimeter. The meter must be connected in series with the circuit (you must break the circuit and let current flow through the meter). Warning: Connecting a meter in current mode across a voltage source (parallel) will blow the meter's fuse.Measure Voltage (Volts - V)Connect the meter in parallel (across the component or power source). Ensure you select AC (V~) for wall outlets or DC (V=) for batteries.Detect Short Circuit (Continuity)Set the dial to the continuity mode (often marked with a sound wave symbol). Touch probes to two points. If resistance is near zero (a short), the multimeter will beep. This is excellent for checking broken wires or fuses.Non-Contact Voltage (NCV)Many modern multimeters (2020s era and later) include an NCV sensor at the tip. This allows you to detect the presence of live AC voltage in a wire or outlet without touching the metal contacts.Test ICs and ComponentsWhile multimeters can check supply voltage (VCC) and ground pins on Integrated Circuits (ICs), troubleshooting internal IC logic is often better done with an oscilloscope or logic analyzer. However, a multimeter is perfect for finding shorted pins. Ⅴ Multimeter Usage Tips1. Probe Safety: Never touch the metal tips of the probes during a test. Always hold the insulated handles behind the finger guards.2. Switching Gears: Never rotate the selection dial while the probes are connected to a live high-voltage circuit. This can cause internal arcing. Disconnect probes, switch modes, then reconnect.3. Battery Maintenance: If the multimeter will not be used for a long period, remove the internal battery to prevent leakage and corrosion.4. High Voltage Awareness: Be aware of the "CAT" rating of your meter. Do not use a CAT II meter for main service panels (which require CAT III or CAT IV ratings).Video: How to Use a Multimeter?Ⅵ How to Find Circuit Faults with Multimeter6.1 General Troubleshooting Strategy1. Visual InspectionBefore measuring, look for charred components, swollen capacitors, or loose wires. Touching components (cautiously) to check for overheating can also identify shorts.2. Voltage TracingMeasure the voltage at various points in the circuit starting from the power source. If voltage is present at point A but missing at point B, the fault lies between them (e.g., a broken trace or failed component).3. Hidden TroubleshootingIntermittent failures are often caused by "cold" solder joints or loose connectors. Continuity mode is vital here. Wiggle wires while testing continuity; if the beep stops, you have found a loose connection. 6.2 Measuring Techniques6.2.1 Voltage Measuring PointsTesting voltage against a "Ground" reference is the standard method. Connect the black probe to the circuit Ground (GND) and use the red probe to touch various test points (VCC, output pins). Deviations from the expected voltage (e.g., getting 2V on a 5V line) usually indicate a problem.6.2.2 Measuring Parameters Selection① Always check if you are measuring AC or DC. Measuring AC voltage while in DC mode (or vice versa) will give false readings.② For signal circuits, remember that standard multimeters measure "Average" or "RMS" voltage. They may not accurately show fast data pulses—an oscilloscope is required for that.③ Polarity: In DC mode, if you reverse the probes (Red on negative, Black on positive), the screen will simply show a negative sign (e.g., -12V). This is normal and safe for digital meters. Ⅶ How to Measure Current with Digital MultimeterMeasuring DC Current1. Insert the Red test lead into the jack marked "mA" (for low current) or "10A/20A" (for high current). Insert the Black lead into "COM".2. Turn the dial to the DC Current setting (A=).3. Break the circuit: You must physically interrupt the wire and place the multimeter probes in line with the circuit so current flows through the meter.4. Power on the circuit and read the value.Figure 1. Measuring Operating Current of a DC Relay If the reading is negative, your probes are reversed (current is entering the black probe). This does not damage a digital meter.Figure 2. Measuring DC Current in Series Measuring Current with an Analog MultimeterWith analog meters, polarity matters. If you connect probes backward, the needle will deflect to the left (below zero), potentially damaging the mechanism. Always ensure Red connects to the more positive side and Black to the negative side.Figure 3. Series connection with Analog Multimeter Figure 4. Reading the Scale on an Analog Multimeter Measuring AC CurrentThe process is similar to DC, but you must select the AC Current setting (A~). For high currents (e.g., household mains), it is highly recommended to use a Clamp Meter instead of a standard multimeter for safety. A clamp meter measures current via magnetic fields without breaking the circuit.Figure 5. AC Measurement Diagram Ⅷ Which is Better: Analog or Digital Multimeter?For 99% of users in 2025, the Digital Multimeter (DMM) is superior. It offers higher accuracy, higher input impedance (which means it doesn't affect the circuit you are testing), and easier readability. Analog meters are now a niche tool, primarily used by technicians who need to see real-time trends or rapid fluctuations that a digital digital might miss (though modern DMMs with "bar graphs" solve this).Analog MultimeterDigital MultimeterVisualizes trends/fluctuations easily via needle movement.Easy to read exact numbers; no parallax errors.Lower input impedance (can load down sensitive circuits).High input impedance (better for delicate electronics).Susceptible to damage from physical shock (drops).generally more rugged and durable.Often requires manual zeroing and range selection.Includes Auto-ranging, Auto-polarity, and specialized functions.Both meters have their place, but if you can only afford one, buy a Digital Multimeter. They are now available at very affordable price points without sacrificing essential accuracy. Ⅸ Best Multimeter Brands in 2025When selecting a multimeter, reliability and safety are paramount. Brands differ by their target audience: Professionals (industrial use) vs. Hobbyists (home use). Below are reputable brands recognized in the industry today.*Etekcity (Budget/Home)Mastech GroupInnova (Automotive)Klein ToolsKeysight Technologies (formerly Agilent)BrymenKaiweets / AstroAI (Budget)Fluke (Professional Gold Standard)ExtechAmprobeHioki Ⅹ Frequently Asked Questions1. What is a multimeter primarily used for?A digital multimeter is a diagnostic tool used to measure electrical values—principally voltage (Volts), current (Amps), and resistance (Ohms). It is standard equipment for electricians, automotive mechanics, and HVAC technicians. 2. What is "Auto-Ranging"?Auto-ranging is a feature on digital multimeters where the meter automatically selects the correct measurement range for the signal it detects. You simply select "Voltage," and the meter decides if it's millivolts or hundreds of volts. This saves time and prevents setup errors. 3. Why is "True RMS" important?True RMS (Root Mean Square) allows a multimeter to accurately measure AC voltage even when the sine wave is distorted (common in motor drives, HVAC systems, and computers). Non-True RMS meters are only accurate on perfect sine waves. 4. Can I use a multimeter to test a battery?Yes. Set the multimeter to DC Voltage (V=). Connect the red probe to the positive (+) terminal and black to negative (-). A fully charged 1.5V AA battery should read greater than 1.5V (usually 1.6V). If it reads below 1.2V, it is dead. 5. What are CAT ratings?CAT ratings (Category I, II, III, IV) define the safety level of the meter. CAT III or CAT IV is recommended for testing household wiring and mains power to protect against dangerous transient voltage spikes.

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. 

IntroductionA potentiometer is a three-terminal resistor with a sliding or rotating contact. It is an adjustable voltage divider with two static contacts and one moving contact. The moving terminal is a wiper that travels across the resistance element, usually in an arc controlled by a rotary knob. Rotating the knob gives a ratiometric division of the potential across the resistance element. Potentiometer generally used in speakers and receivers for volume control. In addition, it cannot directly control the motor because its power is too small. When potentiometer acting as a voltage divider, the absolute resistance of the potentiometer will not affect the output voltage, and its output voltage is proportional to the input voltage.Figure 1. Potentiometer StructureCatalogIntroductionⅠ Potentiometer WiringⅡ Potentiometer Symbol and Diagram DescriptionsⅢ Potentiometer Voltage Divider Circuit BasicsⅣ Potentiometer Resistance MeasuresⅠ Potentiometer WiringThe potentiometer can be used as a three-terminal component or a two-terminal component. The latter can be regarded as a rheostat. For a general potentiometer (three pins), the slider near the center which is a resistance wire. The two pins at both ends of the resistance wire are connected to the input and the ground (some are not connected), respectively. That is, one pin is connected to the input signal and the other pin is grounded. At this time, the resistance wire has a total resistance value on the two sections. You move the sliding piece to go across this resistance wire to get a variable resistance. If the input and output signals are reversed, the sliding direction of the slide is opposite to the resistance change.How to Wire a Potentiometer1) For a potentiometer (or a trimming resistors) with traditional pins (three pins), the resistance at both ends is fixed, and the resistance of the middle pin is variable. That is, the terminal on both sides of the potentiometer are total resistance, and the middle is changing. For example, the power supply is connect from any one contact on resistor sides and output from the middle contact, and the voltage changes with the rotation of the middle contact.Figure 2. Potentiometer Voltage Divider Output2) Although the resistance can vary with the slider, the total resistance value of pins is fixed. At this time, the potentiometer is equal to a current controller, and the selected current output terminals must be the sliding terminal. Commonly used potentiometers have poor resistance accuracy and poor temperature coefficient, but as long as the resistance of the potentiometer is uniform, so is the output voltage value.Figure 3. Potentiometer as Voltage Divider3) If a potentiometer used as a variable voltage divider, one contact connects to the input voltage, the middle contact connects to the output voltage, and the other contact can be grounded. When the rotary handle or sliding handle of the potentiometer take action, the movable contact slides on the resistor. At this time, an output voltage that has a certain relationship with the external voltage, wiper angle and travel stroke.4) If a potentiometer used as a variable resistor, one end connects to the input voltage, the middle end connects to the output, and the other end can be suspended or connected to the middle end to obtain a smooth and continuously changing resistance value.Figure 4. Potentiometer Connected as Variable Resistor As above mentioned, a potentiometer can be connected as a variable resistor, if you want to know more info, you can get it from The Differences Between Potentiometer and Adjustable Resistor. Ⅱ Potentiometer Symbol and Diagram DescriptionsNamePotentiometer SymbolDescriptionNormal PotentiometerUse RP (resistor potentiometer) to represent the potentiometer. The symbol in the figure mark the 3 pins of the potentiometer, indicating the chip pins.Potentiometer SwitchS1 is a switch attached to the RP, and S1 is controlled by the RP rotary handle. When you start to turn the handle, after the switch closes, this circuit is the same as a normal potentiometer. This kind of potentiometer is mainly used in volume control circuits with power switches.As a Variable ResistorThe potentiometer at this time can be regarded as a variable resistor.A Potentiometer with dual portDivide the 3 pins of the potentiometer into 4 ends to form a dual-port circuit. That is, terminals 1 and 2 input signals, terminals 3 and 4 output signals, and terminals 2 and 4 are common terminals, which usually connected to the ground of the line.Dual Gang PotentiometersIt has two single potentiometer circuit symbols, which are connected by a dotted line to indicate that the resistances of dual gang potentiometer are adjusted simultaneously, that is, their resistance values increase or decrease at the same time.Half Linear StrokeThis is a special dual gang potentiometer. Two potentiometer travel strokes are synchronized, but their resistance changes are not the same during adjustment. Only one mechanical stroke of this kind of potentiometer changes in resistance, and the resistance value of the silver zone is zero of another one. The silver zone with no resistance is indicated by shading in the circuit symbol. When the moving contact slides up from the middle, the moving piece RP-1 will enter the silver zone, and RP-2 will enter the varistor area; when the moving handle slides down from the middle position, the RP-2 will enter the silver zone, and RP-1 enters the varistor zone. This special potentiometer can be used in a stereo balance controller circuit (a control circuit in stereo equipment).With Central TapIt has one more pin than the ordinary potentiometer, that is, the tapping pin. The tapping pin is set at the middle resistance of the potentiometer, and the resistance between the tap and the two fixed contacts is equal. There are also potentiometers whose taps are not set in the middle position.Figure 5. Potentiometer CircuitsⅢ Potentiometer Voltage Divider Circuit Basics1) The resistor of the potentiometer is mostly made of polycarbonate synthetic resin. The following items should be avoided: ammonia, other amines, aqueous alkali solutions, aromatic hydrocarbons, ketones, lipid hydrocarbons, strong chemicals (excessive pH), etc., otherwise it will affect potentiometer performance.2) When soldering the potentiometer terminals, avoid using water-capacitive flux, which will cause metal oxidation and mold material. Using inferior flux, poor soldering may cause problems in soldering, resulting in poor contact or open circuit.3) If the soldering temperature of the terminal is too high or the soldering time is too long, it may cause damage to the potentiometer. The temperature range of the plug-in potentiometer is 235℃±5℃; the wire bonding type is 350℃±10℃, and the soldering point should be more than 1.5mm away from the potentiometer body. In addition, avoid heavy pressure on the terminals, otherwise it is easy to cause poor contact.4) During soldering, the height of the flux entering the printing machine board should be adjusted properly, and it should be avoided to affect the potentiometer. Because it will cause poor contact between the brush and the resistor, or result in noise.5) The potentiometer is better in the voltage adjustment structure.6) Avoid condensation or water droplets on the surface of the potentiometer, and avoid using potentiometer in a humid place to prevent insulation deterioration or short circuit.7) When fixing the screws of the rotary potentiometer, the strength should not be too strong to avoid poor rotation. For the direct-sliding potentiometer, avoid using too-long screws, otherwise it may hinder the movement of the sliding handle and even damage the potentiometer itself.8) In the process of putting the potentiometer on the knob, the pushing force should not be too large (don’t exceed the parameter index of the rated pushing and pulling force), otherwise it may cause damage to the potentiometer.9) The rotary force of the potentiometer will decrease as the temperature increases, and become smaller as the temperature decreases. If the potentiometer is used in a low temperature environment, it needs special low temperature resistant grease.Figure 6. Potentiometer Voltage Divider Circuit Connections10) If the shaft or sliding handle of the potentiometer is too long, it is easy to shake and cause the instability of the circuit signal.11) The carbon film of the potentiometer can withstand the ambient temperature of 70℃, and its function may be lost when the temperature is higher than 70℃.12) For a adjustable potentiometer, when the DC is allowed to pass through the movable contact, the problem of anodic oxidation may occur. In this case, it is best to connect the component with the negative end and connect the moving contact with the positive end.13) The load current of the adjustable potentiometer cannot be increased at will to keep circuit safety. And actual current measurement would be to put ammeter in series with the potentiometer in the active circuit.14) Do not exceed the rated power when using the adjustable potentiometer. For example, when the power dissipation exceeds the rated value, it will cause the potentiometer to overheat.15) A Potentiometer is sensitive if it is capable of measuring very small potential differences, and shows a significant change in balancing length for a small change in potential difference being measured.16) A DC potentiometer is created by dropping voltage across a set of resistors in series. Different resistors will produce different values. In AC potentiometer, one can use resistors or even inductors or capacitors as impedances which will drop voltages and provide a voltage less than applied voltage.17) If positioned the potentiometer wiper on the center of the resistor element then the voltage at the wiper is 50%; if the wiper is positioned 1/4 of the way from the negative node then the wiper voltage is 1/4th the entire voltage.18) Potentiometer nomenclature: It generally use the direct marking method. Letters and numbers are marked on the potentiometer shell to indicate their model, nominal power, resistance, and the relationship between resistance and rotation angle.If you have any interest, with a deep reading, you can get more info from What is the Voltage Divider Basic and Rule. Ⅳ Potentiometer Resistance MeasuresThe main checking requirements for the potentiometer are: ① The resistance value meets the circuit requirements. ② The connection between the center sliding end and the resistor is good, and the rotation is smooth. For potentiometer with switches, the switch action should be accurate, reliable and flexible. Therefore, the performance of the potentiometer must be checked before use.1) Resistance measurement: First, select the appropriate gear of the multimeter according to the resistance of the measured potentiometer. Whether the resistance between the two ends of the AC is consistent with the nominal resistance. Rotate the sliding contact, and its value should be fixed. If the resistance indicates infinite, the potentiometer is damaged.2) Then measure the contact between the center end and the resistor, that is, the resistance between the two ends of BC. The method is to set the ohm range of the multimeter in the appropriate range. During the measurement, slowly rotate the shaft and observe the reading of the multimeter. Normally, the reading changes steadily in one direction. If there is a jump, drop, or blockage, it means that the movable contact has failures.3) When the center end slides to the head or the end, the resistance value of the center end and the coincident end is 0 for an ideal state. In the actual measurement, there will be a certain value (generally determined by the nominal value, generally less than 5Ω), which is normal. Frequently Asked Questions about Potentiometer Voltage Divider1. How can a potentiometer be used as a voltage divider?Potentiometers can be used as voltage dividers. To use the potentiometer as a voltage divider, all the three pins are connected. One of the outer pins is connected to the GND, the other to Vcc and the middle pin is the voltage output. Basically, the voltage divider is used to turn a large voltage into a smaller one. 2. How does a potentiometer affect voltage?When the potentiometer resistance is decreased (the wiper moves downwards) the output voltage from pin 2 decreases producing a smaller voltage drop across R2. Likewise, when the potentiometer resistance is increased (the wiper moves upwards) the output voltage from pin 2 increases producing a larger voltage drop. 3. What is a dual gang potentiometer?It means two potentiometer combined on the same shaft, enabling the parallel setting of two channels. Most common are single turn potentiometers with equal resistance and taper. 4. How many volts can a potentiometer handle?100 voltsIf the potentiometer is rated at 1 Watt, you can only apply a maximum of 100 volts. I.e 10 mA. That applied to the voltage across the full 10000 ohms. That also means that you cannot pass more than 10 mA into the Wiper.

IntroductionDefinition: A ceramic capacitor is a capacitor that has a ceramic dielectric as its dielectric material. Multi-layer ceramic capacitors and ceramic disc capacitors are the two most common types. The dielectric in a ceramic capacitor is ceramic. Ceramics, a well-known insulator, is one of the first materials used in the manufacture of capacitors. Ceramic capacitors come in a variety of geometric forms, some of which have been phased out due to size, parasitic effects, or electrical characteristics, such as ceramic tubular capacitors and barrier layer capacitors. Multi-layer ceramic capacitor, also known as ceramic multi-layer chip capacitor (MLCC), and ceramic disc capacitor are the two types of ceramic capacitors most widely used in modern electronics.                                                                                                                                             Typical Multilayer Ceramic Capacitor With a production volume of about 1000 billion devices per year, MLCCs are the most widely used capacitors. Due to their small size, they are commonly used and manufactured using SMD (surface-mounted) technology. Ceramic capacitors are usually made with very small capacitance levels, ranging from 1nF to 1F, with a maximum capacitance of 100F. Ceramic capacitors are thin, and their maximum rated voltage is low. Since they lack polarity, they can be safely linked to AC electricity. Due to low parasitic effects including resistance and inductance, ceramic capacitors have excellent frequency response. Ceramic capacitors have the following advantages over other capacitors: small size, large capacity, good heat resistance, mass production suitability, and low price.CatalogIntroductionCatalogⅠThe Origin of Ceramic CapacitorsⅡ Classification of Ceramic Capacitors  2.1 Semiconductor Ceramic Capacitors  2.2 High Voltage Ceramic CapacitorsⅢ Characteristics  3.1 Precision and Tolerance  3.2 Size Advantages  3.3 High Voltage and High PowerⅣ Ceramic Dielectric TypesⅤ Construction and Properties of Ceramic Capacitors  5.1 Ceramic Disc Capacitors  5.2 Multi-layer Ceramic Capacitor (MLCC) Ⅵ Advantages and Disadvantages  6.1 Advantages  6.2 DisadvantagesⅦ Applications for Ceramic CapacitorsⅧ How to read ceramic capacitor value?Ⅸ How to Test Ceramic Disc CapacitorⅩ FAQⅠThe Origin of Ceramic CapacitorsLombardi from Italy invented ceramic dielectric capacitors in 1900. It was discovered in the late 1930s that by adding titanate to ceramics, the dielectric constant can be doubled, resulting in cheaper ceramic dielectric capacitors. Ceramic capacitors were first used in military electronic equipment around 1940, following the discovery of the insulation properties of BaTiO3 (Barium titanate), the primary raw material for today's ceramic capacitors. Around 1960, ceramic laminate capacitors became commercially available. It had become an essential part of electronic devices by 1970, thanks to the rapid growth of hybrid IC, computers, and portable electronic devices. Ceramic dielectric capacitors currently account for approximately 70% of the overall capacitor market.                                                                                                             Historic Ceramic CapacitorsⅡ Classification of Ceramic Capacitors2.1 Semiconductor Ceramic Capacitors(1)Surface Layer Ceramic CapacitorThe miniaturization of capacitors, that is, the capacitor obtains the largest possible capacity in the smallest possible volume, which is one of the development trends of capacitors. For the separation of capacitor components, there are two basic approaches to miniaturization: ①Make the dielectric constant of the dielectric material as high as possible; ②Make the thickness of the dielectric layer as thin as possible. Among ceramic materials, the dielectric constant of ferroelectric ceramics is very high, but when ferroelectric ceramics are used to manufacture ordinary ferroelectric ceramic capacitors, it is difficult to make the ceramic dielectric very thin. Firstly, due to the low strength of ferroelectric ceramics, it is difficult to carry out actual production operations because it is easy to fracture when it is thin. Secondly, when the ceramic medium is fragile, it is easy to cause various structural defects and the production process will be challenging.(2)Grain Boundary Layer Ceramic CapacitorThe surface of BaTiO3 semiconductor ceramics with sufficiently developed grains is coated with appropriate metal oxides (such as CuO or Cu2O, MnO2, Bi2O3, Tl2O3, etc.), and heat treatment is performed under oxidizing conditions at appropriate temperatures. Then the substance will form a low eutectic solution phase with BaTiO3, rapidly diffuse and penetrate into the ceramic along with the open pores and grain boundaries, forming a thin solid solution insulating layer on the grain boundaries. The resistivity of this thin solid solution insulating layer is very high (up to 1012~1013Ω·cm). Although the ceramic grain interior remains as semiconductor, the entire ceramic body is shown as the dielectric constant of 2×104 to 8×104 dielectric medium. Capacitors made with this kind of porcelain are called boundary layer ceramic capacitors, or BL capacitors for short.2.2 High Voltage Ceramic CapacitorsThe ceramic materials of high-voltage ceramic capacitors are barium titanate-based and strontium titanate-based. Barium titanate-based ceramic materials have the advantages of high dielectric coefficient and good AC withstand voltage characteristics, but also have the shortcomings of capacitance change rate with the increase of medium-temperature and decrease of insulation resistance. The Curie temperature of strontium titanate crystal is -250℃, and it is a cubic perovskite structure at room temperature.  It is a para-electric body, and there is no spontaneous polarization phenomenon. Under high voltage, the dielectric coefficient of strontium titanate ceramic material changes little. The dielectric loss tangent value (tgδ) and capacitance change rate are small, which makes it a high-voltage capacitor dielectric. 2.3 Multilayer Ceramic CapacitorsMultilayer ceramic capacitors are the most widely used type of electronic component. They are stacked alternately in parallel with the internal electrode material and ceramic body and fired into a whole, also known as chip monolithic capacitors. It has the characteristic of small size, high specific volume and high precision. It can be mounted on a printed circuit board (PCB) and hybrid integrated circuit (HIC) substrates. It can effectively reduce the volume and weight of electronic information terminal products (especially portable products), and also improve product reliability.                                                             Multilayer ceramic capacitors conform to the IT industry's development direction of miniaturization, lightweight, high performance, and multifunction. The outline of the national vision goal for 2010 clearly puts forward that new components such as surface-mounted components should be the development focus of the electronic industry. It is not only simple packaging, good sealing, and can effectively isolate the opposite electrode. MLCC can store charge, block DC, filter merge, distinguish different frequencies and tune the circuit in the electronic circuit.  It can partially replace organic film capacitors and electrolytic capacitors in high-frequency switching power supplies, computer network power supplies and mobile communication equipment. What's more, it can greatly improve the filtering performance and anti-interference performance of high-frequency switching power supplies.                                                Ⅲ Characteristics3.1 Precision and ToleranceCeramic capacitors are currently available in two classes: class 1 and class 2. When high stability and low losses are needed, Class 1 ceramic capacitors are used. They are extremely precise, and the capacitance value remains constant regardless of applied voltage, temperature, or frequency. Within a total temperature range of -55 to +125 °C, the capacitance thermal stability of the NP0 series of capacitors is 0.54%. The nominal capacitance value's tolerances can be as poor as 1%. Class 2 capacitors have a large capacitance per volume and are used in less sensitive applications. Their thermal stability in the operating temperature range is usually 15%, and nominal value tolerances are about 20%.3.2 Size AdvantagesMLCC devices outclass other capacitors when high component packing densities are needed, as is the case in most modern printed circuit boards (PCBs). The “0402 multi-layer ceramic capacitor package” measures just 0.4 mm x 0.2 mm to demonstrate this point. There are 500 or more ceramic and metal layers in such a box. As of 2010, the minimum ceramic thickness was on the order of 0.5 microns.3.3 High Voltage and High PowerCeramic capacitors that are physically bigger and can withstand even higher voltages are known as power ceramic capacitors. These are much larger than the ones used on PCBs, and they have specialized terminals for connecting to a high-voltage supply safely. Ceramic capacitors with a power specification of much more than 200 volt-amperes can withstand voltages ranging from 2 kV to 100 kV. Printed circuit boards use smaller MLCCs that are rated for voltages ranging from a few volts to several hundreds of volts, depending on the application.Ⅳ Ceramic Dielectric TypesUnlike other capacitor types such as tantalum capacitors and electrolytic capacitors, ceramic capacitors may use a variety of dielectrics. These various dielectrics give capacitors very different properties, so in addition to deciding on a ceramic capacitor, a second decision about the type of dielectric may be needed. Popular ceramic capacitor dielectrics, such as C0G, NP0, X7R, Y5V, Z5U, and many others, are frequently listed in distributors' lists. However, determining which form is best necessitates a little more study. Ceramic Capacitor Dielectric ClassesSome industry organizations have identified a range of ceramic dielectric application classes to make selecting capacitors with the appropriate dielectric easier. These application groups divide the various ceramic capacitor dielectrics into separate classes based on the anticipated application.     International bodies such as the IEC (International Electrotechnical Commission) and the EIA (Electronic Industries Alliance) have standardized these ceramic capacitor classes.Ⅴ Construction and Properties of Ceramic Capacitors5.1 Ceramic Disc CapacitorsCeramic disc capacitors are made by coating a ceramic disc on both sides with silver contacts. These devices can be constructed from several layers to achieve higher capacitances. Ceramic disc capacitors are usually through-hole components that have lost popularity due to their large scale. If capacitance values allow, MLCCs are used instead. Ceramic disc capacitors have capacitance values ranging from 10pF to 100pF and voltage ratings ranging from 16 volts to 15 kV and beyond.                                                                    5.2 Multi-layer Ceramic Capacitor (MLCC)MLCCs are made by combining finely ground granules of paraelectric and ferroelectric materials and layering the mixture with metal contacts alternately. Following the layering, the device is heated to a high temperature and the mixture sintered, yielding a ceramic substance with the desired properties. The capacitance of the resulting capacitor is increased by connecting several smaller capacitors in parallel. MLCCs are made up of 500 layers or more, with a minimum layer thickness of 0.5 microns. As technology advances, layer thickness decreases, allowing for higher capacitances in the same volume.Ⅵ Advantages and Disadvantages6.1 AdvantagesThe following are some of the benefits of using a ceramic capacitor:• This capacitor's physical structure is very compact.• It is well suited for the application of AC signals due to its non-polarized nature.• Signal interference suppression, such as radiofrequency suppression and electromagnetic interference suppression, is improved with these capacitors.• This capacitor is reasonably priced, and it can withstand voltages of up to 100 volts.6.2 DisadvantagesThe following are the drawbacks of using these capacitors:• The capacitance value of these capacitors is less than one microfarad.• These components are also responsible for the Microphonic effect in circuits.• It is unable to withstand high voltages. Since it can easily impact the dielectric present in it. As a consequence, there is a breakdown.Ⅶ Applications for Ceramic CapacitorsGiven that MLCCs are the most commonly manufactured capacitor in the electronics industry, it should come as no surprise that they have a wide range of applications. A resonant circuit in transmitter stations is an interesting high-precision, high-power application. High-voltage laser power supplies, power circuit breakers, and induction furnaces all use Class 2 high-power capacitors. Small-form SMD (surface mount) capacitors are commonly used in printed circuit boards, and capacitors the size of a grain of sand are used in high-density applications. They're also used in DC-DC converters, where high frequencies and high levels of electrical noise put a lot of strain on the components. Since ceramic capacitors are non-polarized and come in a wide range of capacitances, voltage ratings, and sizes, they can be used as a general-purpose capacitor. Ceramic disc capacitors, which are used throughout brush DC motors to reduce RF noise, are familiar to many hobbyists, especially in the field of robotics.Ⅷ How to read ceramic capacitor value?Ceramic capacitors normally have three digits for their values, such as 102, 103, and 101, and the values are in Pico farads. The numbering scheme is simple to understand if you note that picofarads, not microfarads, are used.The worth of a ceramic capacitor with three digits – ABC is AB*10^C Pico Farad. The digit 104 means 10*104pF = 100000pF = 100nF = 0.1uF if ABC is 104. The first two digits of the printed code correspond to the first two digits of the capacitor value, while the third digit indicates the number of zeroes that must be applied to convert the capacitor value to Pico Farad. If we calculate in Nano Farad for values ending with 4, then the reading becomes easy like 104 is 100nF. If we calculate in Nano Farad for values ending with 3, then the reading becomes easy like 103 is 10nF.Some ceramic capacitors are polarized, meaning they have both positive and negative terminals. The capacitor can be identified by its tolerance in addition to its capacitance value. There is many tolerance marking schemes in use, with one and two alphabets being the most common. You don't need to recall them unless you're dealing with a precise circuit. We only looked at ceramic capacitors in direct current (DC) circuits with voltages ranging from 12V to near zero in this short article. Hobbyists are familiar with this collection. It is also useful to be familiar with the tolerance marking scheme for professional purposes. Ⅸ How to Test Ceramic Disc CapacitorCeramic disc capacitors are units used in the computer industry to control voltage for various dielectric functions. Ceramic layers aim to dissipate heat generated by high voltage while also protecting the environment — both internal and external — from damage. Volumetric efficiency is inversely proportional to stability and accuracy with these capacitors, making testing difficult.Step 1 Ceramic capacitors must be tested since they will short out if they are exposed to high voltage. Your monitor can blink or go blank if this happens. This issue can be resolved by removing all of the ceramic capacitors. Ceramic capacitors, on the other hand, can be tested if you have the right tools. Step 2To measure a ceramic capacitor, use a wireless multimeter. The capacitor works properly when the voltage is constant. However, you won't be able to accurately calculate it if the ohmmeter's output and digital capacitance don't match the capacitor's voltage, so the second option is preferable. Step 3To locate the short circuit or assess cases where optical capacitance meters fail to produce shortened readings, use an analog insulation tester. In order to obtain a 12-volt output, set the analog meter to 10 Kohm. This phase is needed for the ceramic capacitor to be tested. You may also use both methods to improve measurement precision if you do want to stop removing the capacitor and test it aboard.Related recommendation: How to Test a Start Capacitor?                                             How to Discharge a Capacitor? Ⅹ FAQ1. What is Ceramic Capacitor?A fixed value type of capacitor where the ceramic material within the capacitor acts as a dielectric is the Ceramic Capacitor. This capacitor consists of more alternating layers with ceramic and also a metal layer which acts as an electrode. The composition of this ceramic material in this capacitor tells about the electrical behavior along with its applications. We can define a ceramic capacitor as A fixed-value capacitor where the ceramic material acts as the dielectric. 2. What are the advantages of ceramic capacitors?Following are the advantages of ceramic capacitors:Manufacturing cost is lessHigh-frequency performance is exhibitedThe stability of the capacitor is dependent on the ceramic dielectric 3. What is the capacitance range for a ceramic capacitor?The typical capacitance range for a ceramic capacitor is 10 pF to 0.1 μF. 4. Can I replace all electrolytic capacitors with ceramic ones?If you can find ceramic capacitors of the correct value, you can certainly do this. Ceramic capacitors are more stable, have a longer useful lifetime, have higher voltage ratings and are not polarized. Be prepared to find that there will be a substantial size difference. 5. What are the differences between electrolytic, tantalum and ceramic capacitors?Ceramic capacitors don't have polarity, their terminals can be interchanged. They are suitable for both ac and dc. They don't have any chemical reaction involved in their work. They have a lesser capacity for the same given size. Electrolytic capacitors have polarity (i.e. they have fixed positive and negative terminal), Suitable for dc only. A chemical reaction involves the formation of aluminum oxide on the electrode. ( Consists of aluminum electrodes in a solution of Ammonium borate).Higher capacity. A tantalum electrolytic capacitor, a member of the family of electrolytic capacitors, is a polarized capacitor whose anode electrode (+) is made of tantalum on which a very thin insulating oxide layer is formed, which acts as the dielectric of the capacitor. A solid or liquid electrolyte that covers the surface of the oxide layer serves as the second electrode (cathode) (-) of the capacitor. 6. What is the time constant for the discharge of the capacitors in (figure 1)?figure 1The equivalent resistance:R= 2*1× 10∧3 = 2000 i©=> the time constant: T= R*C = 2000*1× 10∧-6 = 2×10∧-3s = 2ms 7. How do you read a ceramic capacitor value?The first two digits, in this case, the 10 give us the first part of the value. The third digit indicates the number of extra zeros, in this case, 3 extra zeros. So the value is 10 with 3 extra zeros, or 10,000. Ceramic disc capacitor codes are always measured in pico Farads or pF. 8. How can you tell if a ceramic capacitor is bad?Use the multimeter and read the voltage on the capacitor leads. The voltage should read near 9 volts. The voltage will discharge rapidly to 0V because the capacitor is discharging through the multimeter. If the capacitor will not retain that voltage, it is defective and should be replaced. 9. Do ceramic capacitors degrade over time?Among ceramic capacitors, the capacitance, especially of capacitors classified as a high dielectric constant (B/X5R, R/X7R characteristics), decreases over time. ... When the capacitor cools down below the Curie point, aging starts again. 10. How do you tell the positive and negative of a ceramic capacitor?In general, the ceramic capacitor has no positive and negative poles, and the capacity is generally small. It is often used for signal source filtering, and the polarity is only temporary behavior. This is a kind of non-polar electrolytic capacitor, so it is not polar. 

IntroductionIn electronics, what is clipper? A circuit which removes the peak of a waveform is known as a clipper. Clipper circuit is designed to prevent a signal from exceeding a predetermined reference voltage level. The clipper circuit can be designed by utilizing both the linear and nonlinear elements such as resistors, diodes, or transistors. The diode clipper, also known as a diode limiter, is a wave shaping circuit that limits positive or negative amplitude, or both. In electronics, diode clipper circuits are commonly used to process various signals. It is is a circuit designed to prevent a signal from exceeding a predetermined reference voltage level. Clipping changes the shape of the waveform and alters its spectral components.Clipper Circuits IntroductionCatalogIntroductionⅠ Clipper Circuit Types1.1 Positive Clipper Circuit1.2 Negative Clipper Circuit1.3 Combinational Limiter CircuitⅡ Clipper Circuits Analysis2.1 Clipper Circuit Structure2.2 Clipper Circuit ProblemsⅢ General Forms of Clipper Circuits3.1 Clipper Circuit Description3.2 Common Clipper Circuit ExamplesⅠ Clipper Circuit TypesDiode clipper is a limiting circuit which limits the output voltage. In electronics, a clipper is a circuit designed to prevent a signal from exceeding a predetermined reference voltage level. A basic diode limiter circuit is composed of a diode and a resistor. It is divided into three types: positive clipper circuit, negative clipper circuit and combinational clipper circuit. The positive clipper circuit produces a clipping effect when the input voltage is higher than a certain upper limit value; the negative clipper circuit produces a limit effect when the input voltage is lower than a certain lower limit value; the combinational clipper circuit produces a limit effect when the input voltage is too high or too low. In a positive clipper, the positive half cycles of the input voltage will be removed. During the negative half cycle of the input, the diode is forward biased and so the negative half cycle appears across the output. The clipper circuits are described as following.1.1 Positive Clipper CircuitThe diode in clipper circuit is connected in series to the input signal and that attenuates the positive portions of the waveform. The positive clamping circuit blocks the input signal when the diode is forward biased. During the negative half cycle of an AC signal, the diode is forward biased and allows electric current through it. In following figure, when the input signal voltage is lower than a preset upper limit voltage, the output voltage will change with the input voltage, however, when the input voltage reaches or exceeds the upper limit, the output voltage will remain at a fixed value, so that the signal amplitude is limited at the output.1.2 Negative Clipper CircuitThe diode in clipper circuit is connected in series to the input signal and that attenuates the negative portions of the waveform, is termed as negative series clipper. For the figure below, the diode is series to the input and output. If the diode has ideal switching characteristics, when iu is lower than E, D will not conduct, ou=E; when ui is higher than E, D will conduct, ou=iu. The limiting characteristic of this limiter circuit is shown in the figure.1.3 Combinational Limiter CircuitThis kind of circuit combines the positive and negative limiters together which shows in the following figure. Ⅱ Clipper Circuits Analysis2.1 Clipper Circuit StructureIn the circuit, Al is an integrated circuit (a common component), VT1 and VT2 are transistors, Rl and R2 are resistors, and VDl to VD6 are diodes.Analyzing the effect of VD1 and VD2 in the circuit mainly explains the following points.1) It can be seen from the circuit that the circuit structure of the two groups of diodes are the same. Both play the same role in this circuit, so the working principle of them are the same.2) The pin ① is connected to the base of the transistor VT1 through a resistor Rl. Obviously Rl is a signal transmission resistor. The signal output on the pin ① is added to the base of VT1 through Rl (there is no DC blocking capacitor between pin ① and VT1). From this circuit structure, it can be judged that the pin ① is an output signal pin, and it outputs a composite signal of DC and AC. The purpose of determining that the pin ① is to figure out the specific function of the diode VD1 in the circuit.3) The DC voltage output by pin ① is not high enough to make the external diode in a conducting state. The analysis is: if the DC voltage output by the pin ① is high enough, then VD1, VD2 and VD3 conduct, and the internal resistance becomes small. This will shunt the AC signal output by the pin ① to the ground, so the signal will be attenuated. However, this circuit does not need such attenuation. Therefore, the conclusion drawn from this: VD1, VD2 and VD3 are not turned on by pin ① DC voltage output.4) The output from pin ① is the superimposed signal of DC and AC, which is added to the base of the transistor VT1 through the resistor Rl. VT1 is an NPN transistor. If the amplitude of the positive half-cycle AC signal added to the base of VT1 is very large, which may burn the VT1. When the negative half-cycle signal added to the base of VT1 is large, which has no effect on VT1, because the negative signal on the base of VT1 reduces current.Follow the above circuit analysis, it can be judged that VD1, VD2, and VD3 in the circuit has clipper function, to prevent VT1 from burning out. 2.2 Clipper Circuit ProblemsIn the figure, Ul is the DC voltage in the output of pin ①, U2 is the limiting voltage value.When the AC voltage in the output signal of pin ① is relatively small, the positive half cycle of the AC signal plus the DC output voltage does not make the VD1, VD2 and VD3 conduction. Therefore, all diodes are cut off, which has no effect on the AC signal output by pin ①. Assuming that the positive half-cycle output AC signal by pin ① is very large during a certain period, as shown in the signal waveform, at this time it plus the DC voltage can conduct VD1, VD2 and VD3. If the conduction voltage of each diode is 0.7V, then three diodes is 2.1V. Since the tube voltage drop after conduction is basically the same, that is, the maximum voltage of pin ① is 2.1V. So the excess part of the positive half cycle of the AC signal is limited by the resistor. When the DC and AC output signals at pin ① is less than 2.1V, diodes will not conduct and keep cutoff state, which has no clipping effect on the signal.For the specific details of clipper circuit, there are several explanations as follows.1) The negative half cycle large signal output by the pin ④ will not cause VT1 overcurrent, because it will decrease the base voltage of the NPN transistor and the base current, so there is no need to add the limiter circuit.2) The one-way limiter circuit mentioned above, it can only limit the large signal part of the positive or negative half of the signal, and does not limit the signal in the other half. The other is the combinational limiter circuit, which can limit the positive and negative half-cycle signals at the same time.3) There are many reasons for the abnormal increase of the signal amplitude. For example, the fluctuation of the power supply voltage cause it to increase a lot at a certain moment, and the large-scale interference pulse from the outside into the circuit also causes a certain increase.4) After the three diodes VD1, VD2 and VD3 conduct, the sum of the DC and AC voltages on pin ① is 2.1V. This voltage added to the base of VT1 through resistor Rl is maximum, so as to the current of VT1.5) Since the pin ① is the same as the external circuit of pin ②, the working principle of the limiter circuit is the same. So only one circuit needs to be analyzed when analyzing the circuit.6) According to the characteristics of the series circuit, the current in the series circuit is equal everywhere. It can be known that the three series diodes VD1, VD2 and VD3 are turned on at the same time, or they will be turned off at the same time. Therefore, in the series circuit, a diode is turned on and other diodes are turned on.Ⅲ General Forms of Clipper Circuits3.1 Clipper Circuit DescriptionThere are two types of clippers namely series and parallel. In series clipper, diode is connected in series with the load. In parallel clipper, diode is in parallel to the load.1) Series clippers: if the diode is connected in series with load resistanceUnbiased series clipper: in that case the circuit diode is connected in series with load resistance and no external voltage is applied to the circuit.+ve unbiased series clipper: if the +ve portion of output is clipped its called +ve unbiased series clipper.-ve unbiased series clipper: if the -ve portion of output is clipped its called +ve unbiased series clipper.Biased series clipper: if in the circuit, diode is connected in series with load resistance and external voltage is applied to the circuit+ve biased series clipper: if the +ve portion of output is clipped its called +ve biased series clipper.-ve biased series clipper: if the -ve portion of output is clipped its called +ve biased series clipper.2) Parallel clippers: if the diode is connected in parallel with load resistanceUnbiased parallel clipper: in that case the circuit diode is connected in parallel with load resistance and no external voltage is applied to the circuit.+ve unbiased parallel clipper: if the +ve portion of output is clipped its called +ve unbiased parallel clipper.-ve unbiased parallel clipper: if the -ve portion of output is clipped its called +ve unbiased parallel clipper.Biased parallel clipper: if in the circuit, diode is connected in parallel with load resistance and external voltage is applied to the circuit+ve unbiased parallel clipper: if the +ve portion of output is clipped its called +ve biased series clipper.-ve unbiased parallel clipper: if the -ve portion of output is clipped its called +ve biased series clipper. 3.2 Common Clipper Circuit ExamplesIn general, clippers circuit are classified into two types: Series Clippers, Shunt Clippers, and Dual (Combination) Clippers.Series Clipper: The diode is connected in series with the load resistance. 👇Figure 1. Series Positive ClipperThe positive amplitude waveform is cut, and the negative amplitude waveform is retained, as follows:Figure 2. Series Positive Clipper with Positive BiasThe positive amplitude waveform is cut, and the offset positive voltage is retained on the negative amplitude waveform, as follows:Figure 3. Series Positive Clipper with Negative BiasThe waveform of positive amplitude is cut, and the negative voltage is shifted based on the waveform of negative amplitude, as follows:Figure 4. Series Negative ClipperThe negative amplitude waveform is cut, and the positive amplitude waveform is retained, as follows:Figure 5. Series Negative Clipper with Positive BiasThe negative amplitude waveform is cut, and the positive voltage is offset on the positive amplitude waveform, as follows:Figure 6. Series Negative Clipper with Negative BiasThe negative amplitude waveform is cut, and the negative voltage is offset on the positive amplitude waveform as follows: Shunt Clipper: Diode is in parallel with load resistance in circuit. 👇Figure 7. Shunt Positive ClipperFigure 8. Shunt Positive Clipper with Positive BiasFigure 9. Shunt Positive Clipper with Negative BiasFigure 10. Shunt Negative ClipperFigure 11. Shunt Negative Clipper with Positive BiasFigure 12. Shunt Negative Clipper with Negative Bias Dual (Combination) Clipper: It is desired to remove a small portion of both positive and negative half cycles. 👇Figure 13. Combination ClipperWhen the positive and negative waveforms must be limited, a combinational limiter circuit is required, as follows:Images Reference: Clipper Circuits - Series Clipper, Shunt Clipper, and Dual Clipper Frequently Asked Questions about Diode Limiter and Clipper Circuit1. What is Clipper and clamper?The major difference between clipper and clamper is that clipper is a limiting circuit which limits the output voltage while clamper is a circuit which shifts the DC level of output voltage. ... While clamper is used when we need multiples of the input voltage at the output terminal. 2. What is the function of clipper circuit?In electronics, a clipper is a circuit designed to prevent a signal from exceeding a predetermined reference voltage level. A clipper does not distort the remaining part of the applied waveform. 3. What is Clipper circuit and its types?A clipper is a device which limits, remove or prevents some portion of the wave form (input signal voltage) above or below a certain level, in other words, the circuit which limits positive or negative amplitude ,or both is called chipping circuit. The clipper circuits are of the following types. Series positive clipper. 4. What is the difference between a positive clipper and a negative Clipper?Positive Clipper and Negative Clipper. In a positive clipper, the positive half cycles of the input voltage will be removed. ... During the negative half cycle of the input, the diode is forward biased and so the negative half cycle appears across the output. 5. How does diode clipping work?The Diode Clipper, also known as a Diode Limiter, is a wave shaping circuit that takes an input waveform and clips or cuts off its top half, bottom half or both halves together. This clipping of the input signal produces an output waveform that resembles a flattened version of the input. 6. What is the main purpose of a diode limiter?The diode limiter also called Clipper as it is used to limit the input voltage. A basic diode limiter circuit is composed of a diode and a resistor. Depending upon the circuit configuration and bias, the circuit may clip or eliminate all or part of an input waveform. It limits the output voltage to a specific value. 7. What is the purpose of a clamping diode?The clamping circuit fixes the voltage lower limit to zero, that is, the start of the signal is 0 V. The positive clamping circuit blocks the input signal when the diode is forward biased. During the negative half cycle of an AC signal, the diode is forward biased and allows electric current through it. 8. What is a diode clamping circuit?A clamper circuit shifts the DC level or the reference level of the signal to the desired level without changing the shape of the waveform. The clamper circuit can be designed using the diode, resistor, and the capacitor.