Questions tagged [varistor]

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1answer
69 views

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 ...
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2answers
74 views

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 ...
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1answer
69 views

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 ...
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2answers
34 views

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:...
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1answer
37 views

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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1answer
75 views

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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1answer
54 views

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&...
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0answers
152 views

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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0answers
22 views

Dynamic voltage balancing in series-connected varistors

I have several varistors (of type MOV-14DxxxK) in series connection. Voltage balancing is very good when applying DC voltage. Does anybody know if there would occur problems concerning dynamic voltage ...
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1answer
91 views

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 ...
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1answer
83 views

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?
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1answer
52 views

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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1answer
210 views

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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1answer
43 views

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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1answer
289 views

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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2answers
136 views

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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2answers
97 views

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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1answer
421 views

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....
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1answer
47 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. ...
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2answers
140 views

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 ...
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1answer
114 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 ...
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0answers
47 views

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 ...
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1answer
668 views

Why often is used a varistor 7D471K for 220-240vac surge protection rather than a lower nominal voltage one?

In my "supposedly" surge protected power stripe there is a varistor for surge protection configured to simply short-circuit the entrance wires in case of surge. Checking the model it's a MOV-7D471K ...
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1answer
61 views

Varistor in a DC circuit

I'm employing a Varistor in a simple circuit that will be used in a car. The Varistor is there to ensure that any load dumps / vehicle transients will not result in catastrophe for the circuit. My ...
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1answer
230 views

Calculation of varistor parameters for AC line protection

There is a task to choose a varistor to protect the AC circuit, controlling several coils of magnetic starters. Characteristics: Mains voltage 230-240V AC Frequency: 50Hz Starting current of coils ...
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1answer
104 views

Identify unknown disc-shaped component - markings include VF10 0471K

I am trying to identify this piece, which I believe is a varistor, though I'm not sure. It comes from a Samsung rice cooker. I have attempted numerous google searches on the markings, but I have so ...
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1answer
485 views

Are external components required for HLK-PM01?

Apologies in advanced as this is kind of a vague question and due to my lack knowledge in this specific sector. I'm designing a circuit using a HLK-PM01 as the power supply which is a 3W AC-DC ...
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2answers
780 views

Placement of varistor with respect to fuse

My design includes a pretty standard AC/DC converter powered by mains for intended use at home. For overvoltage and overcurrent protection, I am planning to use a combination of varistor and fuse ...
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1answer
97 views

Trying to ID this component & where to get a couple of them? Is it a varistor?

Here's a photo I made to show back and front of this thing. I think it's a varistor. The main body is roughly 8.5mm in diameter. I straightened the two legs but I think they are SUPPOSED to have ...
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1answer
42 views

Need some help Identify a Varistor

I had a either a surge or a part failure cook a few components on board. The board is rather old from a discontinued product. On the board the only components I've not been able to identify that need ...
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3answers
2k views

Varistor? Purpose and principle

In the AL9910 LED driver datasheet it shows a part, which I assume is a varistor, is it so? Varistors are shown to be connected across L and N lines, but here it is connected in series. Please explain ...
3
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1answer
431 views

Creating a temperature-dependent solar cell in LTSpice (using varistors)

I'm currently working on my master thesis and therefore need to simulate a solar cell in LTSpice. I've already modeled and simulated some examples with constant values. But for a more accurate model, ...
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2answers
174 views

How much buffer room is required for a varistor?

I am working on a circuit board design that uses a fuse resistor for protecting from short circuits and a varistor to protect from over voltage. The board is a simple power supply of only a few watts. ...
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1answer
129 views

What is this solar power RC circuit doing?

I am a CSE student working on a project. We are using a solar powered microcontroller. The solar panel's power goes through a fuse and an RC circuit with a varistor to the charging system. What ...
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1answer
983 views

Why does my varistor cause my fuse to blew up?

I have made the following circuit (copied from a very similar picture on internet): At one side of AC/DC I put a normal fuse. The MOV is a 14D391K 14K391 390V varistor diameter 14mm AC 250V DC 320V ...
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2answers
3k views

How can I compare a TVS diode with a varistor?

For a 120Vac line protection element, comparing this TVS diode: With this varistor: The immediate differences I see are: The varistor is marginally cheaper The varistor specifies a maximum working ...
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2answers
310 views

Can Orcade (PSPICE) actually simulate MOV(Varistors)?

I am using Cadence-Orcade Lite. In it I have a circuit in which I want to note the behaviour of varistors (MOV, PSPICE models exist in Orcade for various varistors). I am using LS40K680QP/EPC Model ...
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0answers
828 views

Power Supply Fuses and Varistor

I wish to build a little decent power supply for my IoT devices, would like also to implement more protection from the live 230V AC side and I decided to put a fast blow glass fuse in a nice holder, ...
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1answer
258 views

Help with identify varistor

Need help identify this varistor. Been trying to figure it out since 5 pm of yesterday. Cannot find anything on it. Any help is greatly appreciated.
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2answers
1k views

Help identifying a varistor?

Need help identifying a component that I think is a varistor. It is burnt so it appears black. The circuit is part of a control module for the headlights and keyless entry on a Lincoln. I want to ...
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1answer
94 views

Discharge of a coil powered by parallel transformers

I have the following circuit: I basically have 2 transformer, one is 230V-8V the other one has a ratio of 1:1, so 230V on the secondary. I'm rectifying the two signals with two full bridge ...
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3answers
789 views

Maximum fuse rating before a MOV (varistor)

I just watched some scary videos of MOV's catching fire and I've flee'd here to ask you guys for help. I understand that it's a good idea to put a fuse in front of a MOV, considering it fails short-...
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1answer
915 views

AC/DC power supply: help to choose fuse, varistor and/or TVS diode

I'm going to use this 12VDC AC/DC power supply . It is the first time that I am going to use one and I have some questions about over voltage protection and peak current protection. These are the ...
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1answer
2k views

Identify Varistor TVR 20471

I got this broken Varistor from an Eaton3S 550VA 300W UPS. Marked TVR 20471* I have tried my best to find a replacement but I can't find a similar one. Any tip or recommendation for a similar one that ...
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2answers
7k views

How to choose the right Metal Oxide Varistor (MOV)

I would like to protect the input of a transformer against high voltage surges but I don't understand how I have to proceed to choose the right MOV despite what I read so far about them. Below is how ...
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2answers
1k views

Is a varistor basically two diodes in series, with opposite polarities?

The typical curve for current vs voltage for a varistor: looks a lot like the 2 reverse voltage regions of a normal diode: Is this equivalent the following, and if not, why not? simulate this ...
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1answer
291 views

Energy dissipation and current decay in this circuit

I have a circuit that looks like this : A 200 A current controlled power supplies delivers the current to a coil (with inductance ~ 5 mH) when the MOSFET is open. The varistor is there to clamp the ...
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0answers
159 views

Trying to identify varistor values off an ancient power supply

Was tricky to get a photo with the markings visible, but as best I can tell the markings read... H L1 1502 ...The scoring down the middle is from where I ...
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1answer
647 views

varistor curve and voltage meaning

Could I get an explanation for these datasheet definitions for a varistor? 1) Max. applied voltage. 2) Min varistor peak volts. 3) Max varistor peak volts. 4) The clamping voltage is known to be ...
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0answers
38 views

VI curve varistor and compere between varistor and arrestor

why we need to connect arrestor in parallel with varistor in some circuit ? and we know both is work to protect against high voltage? like this pic.