Brochure

Varistors Introduction
TECHNICAL NOTE
Technical Note
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Revision: 04-Sep-13
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Document Number: 29079
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SELECTION OF THE CORRECT VARISTOR TYPE
In order to select a ZnO varistor for a specific application,
the following points must first be considered:
1. The normal operating conditions of the apparatus or
system, AC or DC voltage?
2. What is the maximum RMS or DC voltage?
To ensure correct selection of varistor type, two multi choice
selection charts have been prepared, see charts below.
The first chart determines the necessary steady state
voltage rating (i.e. working voltage) and the second chart
determines the correct size (i.e. correct energy absorption).
Multi choice selection chart to determine the necessary steady state voltage rating (i.e. working voltage)