Transistor switch with noise rejection provided by variable capacitance feedback diode

Claim 1

IN AN ELECTRICAL CIRCUIT OF THE TYPE IN WHICH A LOGIC CIRCUIT INCLUDING AN OUTPUT TERMINAL, A PLURALITY OF INPUT TERMINALS AND A PLURALITY OF DIODES PRODUCES A SIGNAL AT ITS OUTPUT TERMINAL UPON APPLICATION OF SIGNALS TO THE INPUTS IN ACCORDANCE WITH A PREDETERMINED LOGIC FUNCTION, THE COMBINATION WITH THE LOGIC CIRCUIT OF A SWITCH COMPRISING A TRANSISTOR HAVING BASE, EMITTER AND COLLECTOR TERMINALS, THE BASE TERMINAL BEING CONNECTED TO THE OUTPUT TERMINAL OF THE LOGIC CIRCUIT, MEANS INCLUDING A SOURCE OF POTENTIAL FOR OPERATING THE TRANSISTOR IN A COMMON EMITTER CONFIGURATION AND FOR OPERATING THE TRANSISTOR IN SATURATION IN RESPONSE TO SIGNALS PRODUCED AT THE OUTPUT TERMINAL OF THE LOGIC CIRCUIT AND A SELENIUM DIODE CONNECTED DIRECTLY TO THE BASE TERMINAL AND DIRECTLY TO THE COLLECTOR TERMINAL IN THE REVERSE BIAS DIRECTION TO MAINTAIN THE DIODE IN THE HIGH RESISTANCE REGION OF ITS CHARACTERISTIC UNDER ALL OPERATING CONDITIONS FOR PROVIDING A VARIABLE CAPACITANCE FEEDBACK FROM THE COLLECTOR TERMINAL TO THE BASE TERMINAL.