PlasmaSheep

PlasmaSheep t1_ixy63lt wrote

Put simply, the MOV acts as an open circuit until the voltage across live/ground or neutral/ground exceeds a "clamping voltage". The MOV then presents almost no resistance, making most of the current flow through it rather than through the device under protection. It gets "used up" because passing current through the varistor affects its structure and increases its clamping voltage.

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