Welding control circuit

Claim 1

A WELDING CONTROL CIRCUIT COMPRISING: FIRST AND SECOND WELDING ELECTRODES; A BATTERY; A WELD CURRENT CONTROL TRANSISTOR HAVING AN EMITTER ELECTRODE, A BASE ELECTRODE, AND A COLLECTOR ELECTRODE; SAID EMITTER ELECTRODE BEING DIRECTLY CONNECTED TO SAID FIRST WELDING ELECTRODE; SAID COLLECTOR ELECTRODE BEING CONNECTED TO ONE TERMINAL OF SAID BATTERY; ANOTHER TERMINAL OF SAID BATTERY BEING CONNECTED TO SAID SECOND WELDING ELECTRODE; TIMING MEANS FOR GENERATING A TIMING SIGNAL OF PRESELECTED DURATION; REFERENCE MEANS RESPONSIVE TO SAID TIMING MEANS FOR PROVIDING A REFERENCE VOLTAGE OF PREDETERMINED MAGNITUDE DURING THE DURATION OF SAID TIMING SIGNAL; FEEDBACK MEANS FOR PROVIDING A FEEDBACK VOLTAGE INDICATIVE OF THE VOLTAGE BETWEEN SAID FIRST AND SECOND WELDING ELECTRODES; COMPARATOR MEANS FOR COMPARING SAID REFERENCE VOLTAGE WITH SAID FEEDBACK VOLTAGE AND FOR PROVIDING A CONTROL SIGNAL INDICATIVE OF THE DIFFERENCE BETWEEN SAID REFERENCE VOLTAGE AND SAID FEEDBACK VOLTAGE; AND MEANS FOR APPLYING SAID CONTROL SIGNAL TO SAID BASE ELECTRODE TO MAINTAIN SAID TRANSISTOR CONDUCTIVE OF CURRENT AND THEREBY ESTABLISH A CURRENT PATH BETWEEN SAID BATTERY AND SAID WELDING ELECTRODES DURING THE DURATION OF SAID TIMING SIGNAL.