Switching circuit

Claim 1

An improved circuit for selectively switching one of first and second input circuits to an output circuit comprising: a. first and second PNP-type transistors each having an emitter, a base, and a collector; b. a first direct-current impedance circuit having a first resistor connected between said emItter of said first transistor and a point of reference potential and a second resistor connected between said collector of said first transistor and said point of reference potential; c. a second direct-current impedance circuit having a source of direct current potential with its positive terminal connected to said emitter of said second transistor and its negative terminal connected to said point of reference potential, and a third resistor connected between said point of reference potential and said collector of said second transistor to render said second transistor normally conductive; d. means connecting said base of said first transistor to a point on said third resistor; e. means connecting said base of said second transistor to a point on said first resistor; f. means connecting said first input circuit to said collector of said first transistor; g. means connecting said second input circuit to said collector of said second transistor; h. means connecting said output circuit to said emitters of both said first and second transistors; i. and means for selectively applying a positive-going voltage through a point on said first resistor to said emitter of said first transistor and to said base of said second transistor for rendering said first transistor conductive and said second transistor nonconductive.