The role of varistor in the ground

The protection performance of the varistor is believed to be very clear to everyone. Using the non-linear characteristics of the varistor, when an overvoltage occurs between the two poles of the resistor, the varistor can clamp the voltage to a relatively fixed voltage value, thereby protecting the latter circuit.

Some customers ask if the varistor is not dummy if there is no ground wire, it has no effect. If there is no ground wire, this varistor will completely lose its effect.

We can analyze the circuit with ground protection. This varistor can prevent the surge voltage generated in the positive half cycle of AC, short circuit it to the ground, and the normal working current and the surge voltage and current in the negative half cycle. It is from the zero line, after returning to the phase line after using the electrical equipment, and then returning to the power supply end. At this time, if there is a "spike" of the surge voltage (or current), it must be the same as the operating current before the varistor is turned on and discharged to the ground, so it is said that there is grounding protection. In the circuit, this varistor, when it works, can protect "half" safety.

When you choose a resistor, you should follow the actual situation. The above answer does not represent everyone's point of view. I hope that you can help solve the problem effectively.