Metal Oxide Varistor (MOV)

MOV’s are semiconductors that protect electronic components and systems from transient over voltage conditions. These clamping devices contain a matrix of zinc oxide grains positioned between two metal plates which serve as electrodes. The boundaries between grains form diode junctions which allow current to flow in only one direction. As a rule, metal oxide varistors exhibit highly non-linear current-voltage characteristics. They have high resistance at low voltages and a low resistance at high voltages. Unlike diodes, metal oxide varistors degrade as they absorb repeated transients and are best combined with other technologies. MOVs provide fast response times, low operating voltages, low capacitance, nominal current draw and low clamping voltage.