Power amplifier control and protective circuit

Claim 1

IN A CIRCUIT FOR PROTECTING A POWER AMPLIFIER AGAINST DAMAGE AND DESTRUCTION DUE TO CURRENT OVERLOAD CONDITIONS AND LOSS OF RF DRIVE, THE COMBINATION COMPRISING: (1) A POWER AMPLIFIER HAVING AT LEAST INPUT, OUTPUT AND COMMON ELECTRODES, SAID INPUT ELECTRODE BEING ADAPTED TO HAVE AN RF SIGNAL IMPRESSED THEREON; (2) A SUPPLY SOURCE COUPLED TO SAID AMPLIFIER FOR PROVIDING OPERATING VOLTAGE FOR SAID AMPLIFIER; (3) MEANS FOR DISABLING SAID SUPPLY SOURCE AND REMOVING ENERGIZING VOLTAGE FROM SAID AMPLIFIER, INCLUDING RELAY MEANS AND RELAY OPERATED CONTACT MEANS IN SAID SUPPLY SOURCE; (A) SOLID STATE RELAY CONTROL SWITCH MEANS CONNECTED IN SERIES WITH SAID RELAY TO CONTROL ENERGIZATION THEREOF; (B) RESISTIVE MEANS COUPLED TO SAID POWER AMPLIFIER INPUT ELECTRODE FOR PRODUCING A VOLTAGE IN RESPONSE TO RF DRIVE SIGNAL IMPRESSED ON SAID INPUT ELECTRODE; (C) MEANS COUPLING SAID RELAY CONTROL SWITCH TO SAID RESISTIVE MEANS TO CLOSE SAID SWITCH AND ENERGIZE SAID RELAY FOR ENABLING SAID SUPPLY SOURCE AND APPLYING OPERATING VOLTAGE TO SAID POWER AMPLIFIER ONLY IF RF DRIVE IS PRESENT;