Questions tagged [varistor]

A varistor is a component with an electrical resistance that varies with the applied voltage. Also known as a voltage-dependent resistor, it has a non-linear, non-ohmic I/V characteristic. (From: Wikipedia)

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Varistor-based SPD device - how does it protect the load?

These common SPD devices are put in the main panel of residences: https://aptghana.com/wp-content/uploads/2020/11/SPD-2.jpg. This basic circuit showcases how they are installed: simulate this circuit ...
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Use MOSFET as low frequency PWM variable resistor for step down regulator

I am trying to replace R2 from this LM2596-based module for a MOSFET-based variable resistor: According to this answer (https://electronics.stackexchange.com/a/15273/148272) it may be possible to use ...
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Snubber circuit with MOV for relays connected in series

I have 5 identical relays (same specifications) whose working input voltage is 24V DC and output voltage is 220V AC. I have a problem that voltage spike due to large capacitance when switch turns on, ...
Choi Moonkee's user avatar
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Using two varistors in series when there is no possibilty of using single component

I need to use Varistor to protect the circuitry from 6kV 1,2/50us impulse. Varistor has to be between input + and - wires. The operational voltage between this two input pins can be up to 1050 V. I ...
Walter Nürnberger's user avatar
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Metal Oxide Varistor Identification / Replacement? Component marking lf9 p27z60 1803

Looking for a suitable replacement or link to where I can purchase them
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Parameters for Varistor SPICE model

Can someone explain to me what the "limit" command in the following SPICE model of a Varistor means? Also, what are v(4) and v(8)? ...
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Variable Resistance in LTspice- Convergence problems + understanding the solver

I've created a variable resitance model in LTspice to simulate the behavior of a Metal Oxide Varistor. The variable resistance is performed with a behavioral source aas follows: ...
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Can this circuit limit power surges?

This circuit I had created based on MOV and a relay, it principle is: if a surge comes the MOV would get activated and should turn the relay thus the surge should be redirected. Notes: Input is ...
Hazardous Voltage's user avatar
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Problems with MOV (Metal Oxide Varistor) simulation in LTspice

I recently ask a question relating this topic because I was having problems with the spice models supplied by the manufacturers wich consists of a logarithmic power law: The problem was of the type &...
Santi Ospina's user avatar
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LTspice error with varistor model and impulse current test

I'm trying to use the TDK varistor spice models in LTspice and there are some things that don't add up. In the figure below you can see the actual equivalent circuit of the TDK model. I know that I ...
Santi Ospina's user avatar
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Need to identify electronic part of an unit of my 1988 Chrysler leBaron. Think it's a varistor but I am not familiar with the code on it

Looking for a replacement part of this varistor.
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Identifying a couple of varistors

I am looking for a replacement for these varistors, but I know nothing about the numbers on them. Please help me make sense of the numbers here; what do they mean, and what type/value are these?
Adam Heikkila's user avatar
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What is the function of the capacitors and MOV on the outlet receptacle of this isolation transformer?

I recently purchase a used Tripp-Lite IS250 isolation transformer off of eBay. Here is the datasheet. It's a fairly open secret that these are not true isolation transformers suitable for a tech bench,...
riptusk331's user avatar
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Resistor identification on a shunt PCB of a battery manager

A battery manager (Victron Energy BMV-602S) has a shunt which has a small PCB attached to it. The manager is able to monitor two batteries - "advanced" monitoring of a leisure battery (B1) ...
Maximilian Wiens's user avatar
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Varistor in series with resistor

I am trying to figure out the behavior of an MOV and a resistor in series. When we connect a resistor in series with an LED to a DC voltage source, in order to determine the resistor value, we ...
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ZNR rating difference between original and replacement PCB

I have a defective AC PCB and its potential replacement. The PCBs are near identical: same voltage zone, same micro controller... except the rating of their 4 ZNR components (surge protection) The ...
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I need help Identifying these two varistors

I need assistance in ordering replacement varistors for the light dimmer switch in my 1998 Nissan Frontier. These are from 2 different switches which have exact part numbers, but the varistors are ...
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What is the function of varistor in this design [closed]

Came across this on internet. The description mentioned this module help prevent relay stick to the contact. Please explain why varistor need to be included in the design if it is to connect in ...
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Help identifying MOV

Need some help in Identifying MOV ZNR E14221 RU068
RedCow's user avatar
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Can I use a normal diode as a Zener/Varistor ? If not, why not? (focus on Varistor use)

When I look at a normal diode graph like that I see the Vz Zener voltage of it looks just like a Zener, so why not using it reverse biased like a Zener? I ask like that because I never saw it being ...
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Confused about back EMF protection in maglock circuit

Straight upfront...electrical engineering is not my forte. However, I am trying to help a client with a particular issue and I'm hoping this community can provide some invaluable insight. They have a ...
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Noise suppression circuits for a 120VAC motor

I am building a circuit for a relay that controls power to a 1000 watt pump motor. I want to do what I can to reduce noise and failure of the circuits from transients etc. Here is my schematic: I ...
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Trying to ID component

Anyone recognize this component or have a NSN or part number? On the back it says: 0Q6Q MEXICO
Christian Apresto's user avatar
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3 answers
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Can placing MOVs on a 240 V input ever be a bad thing?

The power supply of my home lighting keeps failing. So far I have had ten identical power supplies fail. Upon inspection the thing that is always damaged is the electrolytic capacitor after the bridge ...
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PWM output to adjust voltage

I am trying to create a dimming system for this set of 10 leds, using an output from an ESP32. This is what I came up with: Using a 20 volt power supply going through a variable resistor which ...
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AC input safety and filtering: MOV and class X/Y capacitor

Is there a design practice for having both a varistor and a class X or Y capacitor for safety and voltage transient protection on AC circuits? At my work, a previous employee designed a simple AC to ...
the-dstrp's user avatar
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Crack in surface of varistor, likely bad?

I experienced a power surge at my house and some equipment stopped working. one device just had a blown fuse so I soldered in a new one and it worked fine. Another device had an obviously blown ...
Windboater's user avatar
1 vote
1 answer
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Component identification - Power supply circuit component exploded

I am fixing the power supply board of a big mobile sound system. Skytec PA-200 - sadly I could not find any schematics or more information on it. Unfortunately not only an electrolyte capacitor but ...
Lonci's user avatar
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Choose a varistor for a broken PC PSU [closed]

My computer's PSU (Corsair RM 650X) has blown. I've searched a bit online and I have found that this is a common defect due to a low quality varistor put in those kind of PSUs before 2018. I know this ...
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Help identifying a varistor from a fluorescent light tube ballast

I am trying to identify the blown varistor from my fluorescent light tube when I was trying to fix it. I have never seen a manufacturer marking logo on it with a "W" and a cross in the ...
Richard Tan's user avatar
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Electric stove heating element and switches

I am having difficulty in understanding how heating elements and switches work to control how much heat is dissipated in the element of electric stoves or other similar settings. From one perspective ...
Meta_Alchemy's user avatar
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Can I use a back to back Zener as a flyback diode for an AC coil?

I am using the below AC electromagnet to switch on/off a pneumatic system. (It is a pneumatic actuator. I think that is what it is called.) The issue is, when I turn off (disconnect the switch) the ...
Christianidis Vasilis's user avatar
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Help Needed to Identify/Source Varistor S14 K140 0023

Could someone please advise on how I interprate the codes on this Varistor below.. I'm almost there, I can find the S14 / K140 on RS Components, But im unsure about the last 4 digits. RS Website PN:...
RoyBolas's user avatar
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Help Identifying a Component (Varistor)

I am trying to identify the component (I believe is a varistor) in the image below (is from a blender). In another piece of the epoxy I was able to read 14. Should I assume is a 14d241K? Tks! Lino
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Varistor equivalent

I am repairing an old Marantz stereo amplifier and have come across a varistor MV11Y that appears to be the issue. Is anyone able to advise/send me the data sheet for this varistor or perhaps let me ...
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Help identifying a varistor (on a shredder PCB)?

I am trying to identify what I think is a varistor. The markings are : "9 / MVG" and "10K431". I think "10" is the diameter, "K" is the tolerance and "431&...
David Fear's user avatar
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Replacement for TVR 10561 varistor

I am trying to repair the power supply of my PS4. It looks like the fuse has blown out with the TVR 10561 varistor. I can't find this varistor online and I am looking for a replacement. The TVR 10561 ...
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Suitable Substitute for this Varistor MDC Z750 / 40

I am in the process of restoring a vintage EZGO Golf Cart and have came across a component I am unable to locate within the generic golf cart electrical diagram. This varistor is from a 36 volt DC ...
CaptWil's user avatar
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Is this a capacitor or a varistor? How can I figure out specifics?

Is this a capacitor or a varistor? How can I figure out specifics?
Sam's user avatar
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Transient current value

I am working on a SMPS and wanted to size a varistor at the input to protect the rectifier against transient overvoltage (let's say a 1 ms surge). However, by looking at datasheets the maximum ...
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Is this a varistor? WP 270M

I can't figure out whether it's a varistor or any other non-polar capacitor. Please also suggest how to test it.
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Protecting a switching regulator in a 12v automotive system

I'm using a MaxLinear XRP7659 as a 12v -> 5v regulator in my design. The circuit has an average power usage of 80mA @ 12v and a maximum usage of ~500mA @ 12v. I have a 750mA fuse on VIN, along with ...
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Varistors in three phase application

From this Reference Design, I have the following inquiry: Usually in three phase applications I see varistors connected between phase to phase, or between phase to ground. In the reference design, the ...
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Varistor and TVS diodes in series

In the picture below, the input of the rectifier is 690VAC max, so the DC output can reach up to 1kVDC. The DC output goes to a low power DC/DC Converter. In the picture on the left, I'm using a ...
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Why would bridging a varistor with the multimeter leads on any setting have caused the unit to turn on?

So I've been working on fixing this window AC unit for a while, and when I started I knew next to nothing about circuits. At present today, I know a bit about circuits -- enough that i at least know ...
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Do I need to remove the varistor from the circuit to check its validity with DMM?

When I looked up how to measure varistors, I found that the varistor's value should be 0L ohms (Over range, infinite resistance) when measured by a DMM set to test resistance, to indicate its validity....
Ashraf Alshahawy's user avatar
1 vote
1 answer
283 views

Identify a varistor

I'm trying to replace these two varistors from my maytag dryer. I'm not quite sure what party they are. They look like epcos/tdk brand but not sure what the s20 k275 11 08 means, Or the other symbols. ...
Red's user avatar
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Varistor - Place before or after the fuse? [duplicate]

What is safer? Before or after the fuse? In my case the varistor is 10mm, 275Vrms, and it is currently placed after a 250Vac, 7A, 20mm glass fuse. Would the varistor blow the fuse easily if placed ...
abomin3v3l's user avatar
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1 answer
263 views

Why does the high capacitance of a metal oxide varistor affect sensors and signal sensitivity?

I want to know why the high capacitance of metal oxide varistors affects sensors, signal sensitivity. How does capacitance affect sensitivity ? If we add a low capacitor in series will the total ...
Ahmed elmenshawie's user avatar
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0 answers
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Can we use tvs and mov together for thruster?

I want to know if we can use both tvs and mov varistor together ? What will be good for thrusters ? And placement between esc and thruster or before esc? Update: system voltage is power supply ...
Ahmed elmenshawie's user avatar