Coming in a variety of different shapes and sizes, there might be quite a few individuals out there who aren’t quite sure what defines a varistor, or even what its main purpose is. Also known as a voltage-dependant resistor, these devices can be important to a variety of electrical devices. The short answer is that these components have an electrical resistance and for this reason alone, they can be essential to almost any circuit. Let’s look a little closer into what they do and how to find the right one for your needs.
What are they?
The main reason why these components can be so essential is for the simple fact that they can protect circuits from a high voltage surge. While the electrical resistance will often vary depending on the applied voltage and the limits of the component itself, you shouldn’t have an issue if you pick the right one for your needs.
The results of a high voltage surge can be devastating for your circuit, so having a voltage-dependent resistor really can be a necessity in many situations. A capacitor can be installed along the signal lines but in general, it won’t be able to stop a voltage surge, which is why it’s usually worth using varistors to protect your circuit instead.
Even outside of preventing damage, they can help to promote better operating conditions, which is yet another bonus that can come with using them. These can be an excellent compensation or control element in a broad range of circuits and they shouldn’t be overlooked.
Can a varistor fail?
Even though these components can be a necessity and provide several benefits, there are instances where they might fall short. For example, one can burn out if the leakage current is too much for it to handle. Temperatures rising to a certain point can also cause issues too, potentially melting the metal in the component.
Fortunately, there can be solutions to the problem (the cutting in the circuit for example, could help to prevent varistor burnout), which is why it’s worth taking the time to ensure that everything is done correctly for the best possible results.
What type of varistor do you need?
Since there are quite a few different options for varistors and attributes that they all have, it’s important to understand what you need and which voltage-dependent resistors will be ideal for your needs. When shopping for the right one for you, be sure to consider factors like:
- Energy absorption rating
- Response time
- Leakage current
- Rated voltage
- Surge current
- Clamping voltage
