Push-pull semiconductor amplifier apparatus

Claim 1

IN TRANSISTOR AUDIO AMPLIFIER APPARATUS OF THE PUSHPULL CLASS B TYPE WHICH INCLUDES A PAIR OF PUSH-PULL CONNECTED POWER TRANSISTORS, EACH OF SAID TRANSISTORS HAVING AN EMITTER-BASE DIODE JUNCTION, IN WHICH THE TURN OFF WAVEFORM CHARACTERISTIC OF THE TRANSISTORS DOES NOT MATCH THE TURN ON WAVEFORM DUE TO A PHASE LAG BETWEEN THE ALTERNATING SIGNAL BEING APPLIED TO THE TRANSISTOR INPUT AT THE BASE AND EMITTER ELECTRODES AND THE AMPLIFIED SIGNAL APPEARING AT THE COLLECTOR CIRCUIT, WHICH LAG BECOMES SIGNIFICANT AT HIGH AUDIO FREQUENCIES SO THAT THE LEADING EDGE OF THE REVERSE POLARITY SIGNAL ON THE EMITTER JUNCTION DURING THE OFF HALF-CYCLE OF EACH TRANSISTOR INTRODUCES UNWANTED DISTORTION INTO THE AMPLIFIED SIGNAL, THE IMPROVEMENT COMPRISING: A PAIR OF DIODES, EACH DIODE HAVING A RAPID RECOVERY TIME WITH RESPECT TO THE TRANSISTOR RECOVERY TIME, SAID DIODES BEING CONNECTED IN SERIES, RESPECTIVELY, WITH THE BASE ELECTRODES OF SAID PAIR OF TRANSISTORS, SAID DIODES BEING POLED IN THE SAME DIRECTION AS THE EMITTER-BASE DIODE, THE DIODE ALLOWING FORWARD CURRENT TO FLOW IN THE TRANSISTOR BUT DUE TO THE RAPID RECOVERY OF THE DIODE TENDING TO PREVENT A REVERSE BIAS FROM APPEARING BETWEEN THE BASE AND EMITTER ELECTRODES UPON REVERSAL IN POLARITY OF THE SIGNAL, AND A RELATIVELY HIGH RESISTANCE CONNECTED IN PARALLEL WITH EACH OF SAID PAIR OF DIODES TO PROVIDE A HIGH RESISTANCE SHUNT AROUND THE DIODE AND THEREBY ALLOW A SUFFICIENT REVERSE CURRENT TO FLOW TO THE EMITTER JUNCTION THAT THE TURN OFF CHARACTERISTIC OF ONE TRANSISTOR IS MATCHED TO THE TURN ON CHARACTERISTIC OF THE OTHER SO THAT SAID UNWANTED DISTORTION IS ELIMINATED.