Method and apparatus for testing transistors

Claim 1

A circuit for testing bipolar and field effect transistors, comprising a first terminal connector for connection to the collector of a bipolar transistor or to the drain of a field effect transistor, a second terminal connector for connection to the base of a bipolar transistor or to the gate of a field effect transistor, a third terminal connector for connection to the emitter of a bipolar transistor or to the source of a field effect transistor, an oscillator having an a square wave output, means coupling the output of said oscillator to said second terminal connector, and means including an exclusive-or logic gate responsive to the relative phase relationship of the A.C. signals at said first and second terminal connectors to indicate when said signals are 180* out-of-phase, thereby to signify that an operative bipolar or field effect transistor is connected to said terminal connectors.

Claim 5

A method of testing a transistor comprising the steps of applying a square wave drive signal to one electrode of said transistor to develop on another electrode of said transistor a second signal having a frequency equal to that of said drive signal and 180* out-of-phase therewith when said transistor is operative, and utilizing a logic circuit to detect the 180* phase shift between said drive signal and said second signal to indicate that the transistor is operative.

Claim 6

A method of testing a transistor comprising the steps of applying a square wave drive signal to one electrode of said transistor to develop on another electrode of said transistor a second signal having a frequency equal to that of said drive signal and 180* out-of-phase therewith when said transistor is operative, and utilizing a logic circuit to detect the 180* phase shift between said drive signal and said second signal to indicate that the transistor is operative.