公开(公告)号：US3562598A

公开(公告)日：1971-02-09

申请号：US3562598D

申请日：1968-06-20

Applicant: SERVO CORP OF AMERICA

Inventor： DODD ARTHUR E

IPC: H03K17/292 ,  H01H47/18

CPC classification number: H03K17/292

Abstract: A solid-state circuit is described for controlling a railroad signal delay device wherein the time element is formed by a capacitor and a resistor. A polarized relay is employed in a discharge circuit formed by the capacitor, a semiconductor switch and the coil of the relay. Expiration of the time element operates to close the switch in the discharge circuit. The coil of the relay is so oriented in the circuit that during capacitor charging, the magnetic bias is effectively increased, whereas during the discharge initiated by the closing of the semiconductor switch, the bias is overcome.