Solid state, controllable electric switch

Claim 1

A controllable electrical switch comprising; first and second terminals; and actuating means for making electrical connection between said terminals when closing said switch and for breaking said electrical connection when opening said switch; said actuating means including: a. a bistable electromechanical relay having an input electrode coupled to said first terminal and an output electrode coupled to said second terminal and conditionable to one of a low and high impedance state between its input and output electrodes as a function of current flow therein; b. a pair of semiconductor control devices, each having an input circuit and each having an output circuit respectively coupled to said electromechanical relay such that a conductivity condition in one of said devices produces a current flow in said relay as to place it in its low impedance state and such that a conductivity condition in the other of said devices produces a current flow in said relay as to place it in its high impedance state; and c. solid state control means for signal pulsing the input circuits of said semiconductor control devices to change the conductivities thereof, with said changes in conductivity conditions serving to change the current flow through the output circuits of said control devices to change the impedance state of said bistable relay in actuating said electrical switch from a make to a break condition and vice versa; said solid state control means including a pair of pulse triggering circuits, one of which is controllable to first voltage condition for enabling the development of said signal pulses to change the conductivity of said one semiconductor device and controllable to a second voltage condition for inhibiting the development of said signal pulses therefor, and the other of which is controllable to said first voltage condition for enabling the development of said signal pulses to change the conductivity of said other semiconductor device and controllable to said second voltage condition for inhibiting the development of said signal pulses for said other device, and with only one of said pulse triggering circuits being controllable to said first voltage condition at any given instant of time.