Solid-state power switch

Claim 1

A solid-state power switch for selectively energizing a load from a power source in response to a control signal comprising in combination, a transistor oscillator, first means responsive to said control signal for selectively controlling the operation of said oscillator, second means responsive to the output of said oscillator and including a fullwave rectifier and filtering circuit means for generating a gating signal when said oscillator is operative, two transistors having both their emitters and bases in common, means connecting the series combination of the load and the power source to the collectors of said transistors, and circuit means for applying said gating signal between the common bases and the common emitters of said transistors, whereby a selected one of said transistors dependent upon the instantaneous polarity of the output of said power source is rendered conductive irrespective of whether said gating signal is applied between the common bases and the common emitters of said transistors whereas the other of said transistors is rendered conductive only in response to the application of said gating signal to thereby permit energization of said load from an alternating-current power source and from a direct-current power source irrespective of its polarity.