How to select the varistor


Thread Starter


I want to install a varistor for the coil of a 22mm pilot valve. but I do not know how to select it.
the specification of this coil is AC230V,8VA
This is my opinion - please test.

How to Suppress the Arc (RELAY COIL)
For a DC circuit - a simple one amp diode placed parallel with the load will suppress the arc. Select a diode with a voltage rating at least three times or more that of your circuit rating. Connect cathode to positive. Cathode usually
has a dark ring, on the body, on the same side. eg. 1N4004
For an AC circuit use a disk capacitor / resistor placed parallel with the switch. Select a 0.1 mfd 400 V capacitor. Place a 50 - 100 ohm 1/4 watt resistor in series with the capacitor. Place the pieces parallel to the switch. (A Varistor
V130LA10A will also work in AC)

Bob Hogg