Thyristors

Thyristor-based Transient Voltage Suppression (TVS) devices are over-voltage protection devices that approximate an open circuit under normal operating conditions. Application of a voltage across them in excess of some specific value called the breakover voltage causes them to enter a conductive state approximating a short circuit. This state persists until current flow through the device is reduced below a minimum value called "hold current" by some outside influence within the circuit.