Protective circuit for cathode ray tubes using a switch responsive to the power supply to change the bias on the cathode ray tube

Claim 1

A CATHODE RAY TUBE CIRCUIT HAVING ENERGY STORAGE MEANS CONNECTED TO THE TUBE WHICH PRODUCE UNDERSIRABLE BEAM CURRENT UPON DISCHARGE THEREOF, INCLUDING IN COMBINATION, A BIAS CIRCUIT CONNECTED TO THE TUBE AND HAVING A FIRST BIAS CONDITION ASSOCIATED WITH REPRODUCTION OF DESIRED IMAGES BY THE TUBE AND A SECOND BIAS CONDITION FOR INCREASING THE BEAM CURRENT IN THE TUBE BEYOND THE CURRENT ASSOCIATED WITH THE FIRST BIAS CONDITION, A POWER SUPPLY CIRCUIT TO SUPPLY ENERGIZING CURRENT FOR SAID CIRCUIT, AND MEANS OPERATIVE IN THE ABSENCE OF CURRENT FROM SAID POWER SUPPLY CIRCUIT FOR CHANGING SAID BIAS CIRCUIT FROM SAID FIRST CONDITION TO SAID SECOND CONDITION WHEREBY THE BEAM CURRENT IN THE TUBE IS INCREASED TO RAPIDLY DISCHARGE THE ENERGY STORAGE MEANS.