Varistors

Those familiar with Maida Development Company's disc varistors have some idea what a varistor is, but may be unfamiliar with multi-layer varistors (MLVs). MLVs are tiny ceramic chips terminated on each end. They can be used to protect circuits from electrostatic discharge and other high voltage surges. As with disc varistors, the purpose of an MLV is to protect an electronic circuit by carrying away unwanted high voltage spikes. All varistors, including MLVs, have two operating conditions. Under normal operation there is virtually no current draw. The varistor sits idle and uses little power. However, if a large voltage spike comes into the circuit the varistor quickly begins to conduct electricity. The varistor will carry current away from the protected circuit to ground. As soon as the large spike passes, the varistor stops conducting and resumes its idle state. Some people think of this as a resettable fuse. The varistor resets itself after each voltage spike To view the PDF versions of any Maida Spec Sheet requires Adobe's Acrobat Reader 5.0 or higher.