Transistor amplifiers with protective circuit means

Claim 1

A MULTI-STAGE TRANSISTOR AMPLIFIER COMPRISING FIRST AND SECOND TRANSISTOR AMPLIFIER STGES WITH COUPLING MEANS FOR FEEDING SIGNALS AMPLIFIED BY THE FIRST STAGE TO THE SECOND STAGE FOR FURTHER AMPLIFICATION, SAID FIRST STAGE HAVING SUCH GAIN THAT THE OUTPUT SIGNAL FROM THE FIRST STAGE FOR A PEAK INPUT SIGNAL IS OF GREATER AMPLITUDE THAN THE MAXIMUM CONTINUOUS IMPUT SIGNAL WHICH CAN BE HANDLED BY SAID SECOND STAGE DUE TO THE POWER DISSIPATION LIMITS OF SAID SECOND STAGE BUT WITHIN THE PEAK HANDLING CAPACITY OF SAID SECOND STAGE FOR AMPKIFICATION WITHOUT APPRECIABLE DISTORTION, A POWER SUPPLY FOR SUPPLYING OPERATING PONTENTIAL TO SAID FIRST AND SECOND STAGES, A PROTECTIVE CIRCUIT INCLUDING A RESISTANCE ELEMENT HAVING A POSITIVE TEMPERATURE COEFFICIENT OF RESISTANCE CONNECTED IN SERIES BETWEEN THE OUTPUT OF SAID SCOND STAGE ANS SAID POWER SUPPLY FOR PROTECTING SAID SECOND STAGE AGAINST ANY INPUT SIGNAL OF A GIVEN AMPLITUDE HAVING A DURATION EXCEEDING THE PERMISSIBLE DURATION FOR SUCH A SIGNAL DUE TO THE DISSIPATION LIMITS OF SAID SECOND STAGE, SAID PROTECTIVE CIRCUIT FURTHER INCLUDING A CAPACITOR CONNECTED IN SERIES WITH SAID RESISTANCE ELEMENT ACROSS SAID POWER SUPPLY, WHEREBY SAID CAPACITOR PROVIDES A SUBSTANTIALLY CONSTANT OPERATING POTENTIAL TO SAID SECOND STAGE DURING SIGNAL PEAKS OF SHORT DURATION WHEN SAID SECOND STAGE TENDS TO DRAW A LARGE CURRENT, AND SAID RESISTANCE ELEMENT OPERATES TO REDUCE THE OPERATING POTENTIAL ON SAID SECOND STAGE WHEN THE CURRENT DRAWN THEREBY EXCEEDS A PREDETERMINED VALUE FOR A PREDETERMINED PERIOD.