Temperature control trigger employing emitter resistor having value of transistor's base-to-emitter resistance

Claim 1

A TEMPERATURE CONTROL SWITCH COMPRISING, IN COMBINATION, A TRIGGER CIRCUIT CONTAINING A FIRST TRANSISTOR STAGE AND ASSOCIATED CIRCUITRY AND A SECOND TRANSISTOR STAGE AND ASSOCIATED CIRCUITRY, THE TRANSISTOR OF SAID FIRST STAGE AND THE TRANSISTOR OF SAID SECOND STAGE HAVING A RESISTOR COMMON TO THE EMITTER CIRCUITS OF BOTH TRANSISTORS, SAID RESISTOR HAVING A RESISTANCE VALUE NOT GREATER THAN THE BASE TO EMITTER JUNCTION RESISTANCE OF THE SAID FIRST STAGE TRANSISTOR; BIASING MEANS FOR ADJUSTING THE SENSOR SETPOINT OF SAID TRIGGER CIRCUIT TO A VALUE OUTSIDE THE CONDUCTIVE CONDITION OF THE SAID CIRCUIT, SAID BIASING MEANS INCLUDING MEANS TO COMPENSATE FOR CHANGE IN AMBIENT TEMPERATURE OF THE SAID CIRCUIT; A SENSOR OPERATIVELY ASSOCIATED WITH SAID CIRCUIT AND SUPPLYING TO THE BASE OF SAID FIRST STAGE TRANSISTOR A VOLTAGE IN RESPONSE TO CHANGES IN AMBIENT CONDITIONS SURROUNDING THE SAID SENSOR, FOR TRIGGERING SAID CIRCUIT TO CAUSE CURRENT FLOW; AND A SOURCE OF DIRECT CURRENT FOR ENERGIZING THE SAID CIRCUIT.