Question

The thermal runway is avoided in a collector to base bias because_________

(a) of its independence on β

(b) of the positive feedback produced by the base resistor

(c) of the negative feedback produced by the base resistor

(d) of its dependence on β

I got this question in exam.

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

Answer 1

Right choice is (c) of the negative feedback produced by the base resistor

Easy explanation: The self destruction of a transistor due to increase temperature is called thermal run away. It is avoided by the negative feedback produced by the base resistor in a collector to base bias. The IC which is responsible for the damage is reduced by decreased output signal.