System for and method of testing transistors

A method of testing the base-to-emitter voltage-collector-current characteristics of a transistor independent of temperature, said method comprising the steps of:

• providing a constant DC current through the collector of said transistor,
• generating a first DC signal in response to said constant DC current, said first DC signal varying with temperature in accordance with the base-to-emitter voltage of said transistor as a function of temperature;
• applying an AC signal to the base of said transistor,
• generating in response to said applied AC signal a second AC signal in the collector of said transistor, said second AC signal being representative of the transconductance gain of said transistor;
• converting the second AC signal to a second DC signal which varies with temperature in accordance with the transconductance gain of said transistor as a function of temperature;
• modifying at least one of said first and second DC signals so that said first and second DC signals vary with temperature in a substantially equal and opposite manner;
• and
• adding the first and second DC signals, as modified so as to provide a DC signal equal to the base-emitter voltage of said transistor at a predetermined temperature independent of the operating temperature of said transistor.