Determination of the thermal impedance of germanium transistors

Heat dissipation presents a major problem to an engineer designing power transistors. The best way of characterizing a transistor is by quoting the thermal impedance between the collector junction and the stud. This impedance can be analysed into a few elementary impedances, which it is possible to calculate and measure, although the calculation, of which two examples are given, can be only a rough approximation. A method of checking these calculations is developed which can lead to the improvement of the design under consideration.