Method for determining the average temperature of the active region of a transistor based on the change in the output characteristic

Abstract

In the described method of determining the average temperature of the active region of a transistor based on the change in the output characteristic, it is only necessary to assume that the investigated transistor exhibits a constant isothermal collector current in the saturation region, or its change is negligible compared to the thermal change of the actually measured collector current. The method is based on the differential thermal resistance of the active region of small dimensions and the same temperature with uniform generation of thermal power, while the thermal resistance depends only on the temperature of the active region, and knowledge of the electrical parameters of the investigated transistor is not required.