| 摘要 |
PURPOSE:To enable to reduce the power loss at nonoperation of the switching circuit remarkably, by the connection of normally closed contacts of transfer type relays in parallel with LEDs and the parallel connection of normally open contacts with Triacs. CONSTITUTION:Between the T2 terminal and gate terminal of a Triac T controlling a load L, a photothyristors S in antiparallel connection are connected, and a voltage is applied between the terminals T1 and T2 via a resistance R2 of LEDLD in antiparallel connection and photocoupled with each thyristor S. Further, normally closed contacts (a), (c) of a transfer type relay RL excited with a control signal (e) are in parallel connection with LEDLD, and normally open contacts (b), (c) are in parallel connection with the Triac T. Thus, the illumination current of LEDLD is far less than the trigger current of the Triac T, then the power loss at nonoperation of the switching circuit can remarkably be reduced. |
