Temperature control system

Claim 1

A TEMPERATURE CONTROL SYSTEM FOR CONTROLLING THE FLOW OF CURRENT THROUGH A RELAY COIL INCLUDING, IN COMBINATION, A SEMICONDUCTOR AMPLIFYING DEVICE HAVING A CURRENTEMISSIVE ELECTRODE, A CURRENT-RECEIVING ELECTRODE, AND A CONTROL ELECTRODE FOR CURRENT PASSING BETWEEN SAID CURRENT-EMISSIVE AND CURRENT RECEIVING ELECTRODE; MEANS FOR PROVIDING A FLOW OF CURRENT THROUGH SAID RELAY COIL WHEN CURRENT FLOWS AT THE CONTROL ELECTRODE OF SAID AMPLIFIER DEVICE, SAID MEANS CONNECTING (I) SAID RELAY COIL IN SERIES CIRCUIT WITH THE CURRENT-EMISSIVE AND THE CURRENT-RECEIVING ELECTRODES OF SAID AMPLIFYING DEVICE, AND (II) SAID SERIES CIRCUIT TO A SOURCE OF ALTERNATING CURRENT POWER; A TEMPERATURE SENSITIVE BIMETALLIC SWITCH; MEANS FOR PROVIDING A FLOW OF CURRENT AT THE CONTROL ELECTRODE OF SAID AMPLIFYING DEVICE WHEN SAID BIMETALLIC SWITCH IS CLOSED SO THAT THE SEMICONDUCTOR AMPLIFYING DEVICE IS BIASED TO A CURRENT CONDUCTIVE STATE ON ONE-HALF OF EACH A.C. CYCLE, SAID MEANS COMPRISING A RESISTOR CONNECTED IN SERIES CIRCUIT WITH SAID BIMETALLIC SWITCH, SAID SERUES CIRCUIT BEING CONNECTED BETWEEN SAID CONTROL ELECTRODE AND ONE TERMINAL OF SAID SOURCE OF ALTERNATING CURRENT; AND MEANS IN CIRCUIT WITH THE CURRENT-SENSITIVE ELECTRODE OF SAID AMPLIFYING DEVICE FOR COMPENSATING FOR THE EFFECT OF CURRENT LEAKAGE IN THE SEMICONDUCTOR DEVICE SO THAT THERE IS INSUFFICIENT CURRENT FLOW THROUGH SAID RELAY COIL TO MAINTAIN SAID RELAY IN ITS ACTUATED CONDITION WHEN SAID BIMETALLIC SWITCH IS OPEN, SAID MEANS APPLYING A REVERSE BIAS TO SAID CONTROL ELECTRODE FOR REDUCING SAID LEAKAGE CURRENT.