guard ring(redirected from keeper ring)
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guard ring[′gärd ‚riŋ]
A ring-shaped auxiliary electrode surrounding one of the plates of a parallel-plate capacitor to reduce edge effects.
A ring-shaped auxiliary electrode used in an electron tube or other device to modify the electric field or reduce insulator leakage; in a counter tube or ionization chamber a guard ring may also serve to define the sensitive volume.
A device used in heat flow experiments to ensure an even distribution of heat, consisting of a ring that surrounds the specimen and is made of a similar material.