02 Feb 2022

What Happens When a Varistor Fails?

Varistors can be an essential electrical component in many circuits. In certain situations, these can even be a necessity. They are needed to help protect circuits from an overload of excessive voltage – but at any other time, varistors will simply act as capacitors until the surge voltage exceeds its limits.

Generally speaking, varistors aren’t reusable and will need to be replaced if you want to protect your circuit from another voltage surge. Here’s a quick look into what you need to do if you think your varistor has blown.

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pixabay.com image

What happens if your varistor fails?

As a great option for a voltage protection device, it’s important to make sure that you have a working varistor in place (double-check if you aren’t certain). After all, if your varistor is blown, it won’t be able to act as a capacitor anymore, nor will it be able to offer any protection against future overloads. With this in mind, what happens when they fail?

Varistors are often made with a ceramic-like material, so when hit with a sharp, high voltage surge, they will often physically crack. These components can also suffer from electrical punctures when surges aren’t strong enough to cause more severe breakages. To detect damage that isn’t visible, you can check a varistor by touching the free lead with a meter probe and see how much resistance there is. The higher the resistance, the better.

If you’re in need of a replacement, you may be interested in the range available over at https://www.tme.com/us/en-us/katalog/varistors_29/.

How do you choose the right varistor?

Since most circuits will have different requirements and the fact that not all varistors have the same capabilities, it’s often important that you take the time to choose the right one for your needs. One of the most important things you’ll need to consider when choosing a varistor is the peak pulse current of the component. It goes without saying, but if this isn’t high enough, it generally won’t be a good choice.

Other factors are also important to think about, for example, the maximum operating voltage, the mounting method, and even the material it’s made of (you can often find both ceramic and zinc-oxide versions).

Pay a visit to TME

If you’re looking for a wide selection of varistors all in one place, it might be worth checking out the range available at TME.US. With more than 600 different varistors (and many other electrical components), as well as fair and affordable prices, this is a fantastic one-stop shop for all your electronic needs.

By Natalia Ligocka on 02 Feb 2022

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