need an example for varistor calculation

[stoyanoff]

Greatings! Can anyone give me an example how to choose a vristor for a project. I need to know what values the varistor depends on.
Thanks!

 

[crutschow]

The varistor voltage depends upon the normal voltage of the circuit you are protecting.
The power rating of the varistor depends upon the source of the transient that you are protecting against and the impedance of the source.

 

[D.A.(Tony)Stewart]

Let me google that for you ( just this time)