Question

When the temperature is increased, what happens to the collector current after a feedback is given?

(a) it remains same

(b) it increases

(c) it cannot be predicted

(d) it decreases

I have been asked this question by my college director while I was bunking the class.

I would like to ask this question from Thermal Runaway topic in chapter Transistor Biasing and Thermal Stabilization of Electronic Devices & Circuits

Answer 1

Right answer is (d) it decreases

To explain I would say: Before the feedback is applied, when the temperature is increased, the reverse saturation increases. The collector current also increases. When the feedback is applied, the drop across the emitter resistor increases with decreasing collector current and the thermal runway too.