Patent ID: 6034853
Filing Date: 2000-03-07
Classification: H03K

Abstract:
A solid state relay, comprising:a pair of input terminals configured to receive a control signal;a pair of output terminals configured to be connected to an AC circuit, the AC circuit comprising a load and an AC power supply;a thyristor in parallel to the pair of output terminals and configured to switch the AC power supply in response to the control signal;two photothyristor couplers connected in series at a first midpoint connection, wherein the two photothyristor couplers are connected in parallel to the thyristor and are configured to control the thyristor, each photothyristor coupler comprising a photothyristor; andtwo surge arresters connected in series at a second midpoint connection, wherein the two surge arresters are connected in parallel to the pair of output terminals, the two surge arresters being configured to protect the thyristor and the two photothyristor couplers from an excessive voltage level generated by a back current from the AC circuit,wherein the first midpoint connection is connected to the second midpoint connection.