20 April 2017

Metal Oxide Varistor ( MOV ) For Over Voltage Protection of Semiconductor

  • The MOV is a non linear resistor.  There are two metal particles oxide layers are separated by insulation. 
  • When the voltage across MOV increases beyond its specific value, the metal oxide layer becomes conducting and current flow through it. 
  • The symbol and characteristics of MOV is shown in the figure A.
  • When voltage across MOV increases beyond point A, the conduction starts. The relation between voltage and current in the MOV is shown as below.
             I = kVα
  • Where k is constant and value of α lies in the range of 30 to 40.

metal-oxide-varistor.png

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