Transistor checker using alternating line current in phase between emitter and base and emitter and collector for testing power transistors

Claim 1

A TRANSISTOR TESTER COMPRISING IN COMBINATION; AN ALTERNATING CURRENT STEPDOWN TRANSFORMER INCLUDING A PRIMARY ADAPTED FOR CONNECTION TO A SOURCE OF 60 CYCLE ALTERNATING CURRENT POWER AND A LOW IMPEDANCE, LOW VOLTAGE SECONDARY; THREE TERMINALS ADAPTED FOR CONNECTION TO THE COLLECTOR, EMITTER AND BASE OF A POWER TRANSISTOR RESPECTIVELY; A FIRST LIMITING RESISTOR AND CIRCUIT MEANS FOR COUPLING ONE SIDE OF SAID PRIMARY WITH SAID COLLECTOR TERMINAL, A SECOND CURRENT LIMITING RESISTOR AND CIRCUIT MEANS FOR COUPLING THE OTHER SIDE OF SAID PRIMARY WITH ONE OF THE REMAINING TERMINALS SWITCH MEANS FOR CONNECTING THE LATTER SAID TERMINAL TO THE SECOND REMAINING TERMINAL; A RECTIFIER, A RESISTOR, AN INDICATING METER AND SWITCH MEANS FOR CONNECTING SAID RECTIFIER, RESISTOR AND METER IN A SERIES CIRCUIT AND SAID SERIES CIRCUIT IN SHUNT WITH SAID COLLECTOR TERMINAL AND ONE OF SAID REMAINING TERMINALS WHEREIN SAID RECTIFIER AND METER ARE POLLED TO INDICATE THE PEAK VOLTAGE OF A TRANSISTOR CONNECTED TO SAID TERMINALS IN RESPONSE TO THE LIMITED ALTERNATING CURRENT ACROSS SAID PRIMARY IN THE CURRENT BLOCKING DIRECTION; CIRCUIT MEANS FOR CONNECTING THE FIRST SIDE OF SAID SECONDARY TO SAID EMITTER TERMINAL; A RESISTOR AND CONNECTED SWITCH MEANS FOR CONNECTING THE SECOND SIDE OF SAID SECONDARY TO SAID BASE TERMINAL; A RESISTOR AND CONNECTED SWITCH MEANS FOR CONNECTING SAID SECOND SIDE OF SAID SECONDARY TO SAID COLLECTOR TERMINAL; CIRCUIT MEANS INCLUDING A SWITCH FOR CONNECTING SAID METER IN SHUNT ACROSS SAID COLLECTOR AND EMITTER TERMINALS FOR MEASURING THE SATURATION VOLTAGE OF A TRANSISTOR CONNECTED TO SAID TERMINALS; CIRCUIT MEANS INCLUDING A SWITCH FOR CONNECTING SAID METER IN SHUNT WITH THE LAST SAID RESISTOR FOR MEASURING COLLECTOR CURRENT OF A TRANSISTOR CONNECTED TO SAID TERMINALS; A RESISTOR AND SWITCH MEANS IN SERIES FOR CONNECTING THE LAST SAID RESISTOR IN SERIES WITH SAID BASE CONNECTED RESISTOR WHEREBY THE INPUT IMPEDANCE OF A TRANSISTOR CONNECTED TO SAID TERMINALS IS INDICATED BY A CHANGE IN THE COLLECTOR CURRENT INDICATION.