Thermal Transient Effects on Junction Transistors†

Abstract

ABSTRACT Experimental evidence is presented to show that the collector leakage current J co of junction transistors contains a component which does not respond immediately to a step change in temperature, but subsequently undergoes a slow growth, both for positive and negative temperature changes. This occurs even in transistors normally not subject to growth of excess leakage current at constant room temperature. Following a large temperature excursion, recovery at room temperature is slow, being of the order of days. The practical significance of this effecton the use of transistors in d.c. amplifiers, thermometers and as sensing elements, is illustrated with measurements on one transistor and a temperature-compensated d.c. amplifier. It is shown that in the latter case good compensation over a wide temperature range can only be achieved when the temperature transient extends over more than a day.