Question

In an ideal stable self – bias circuit, what should be the current IB with respect to IC?

(a) IB should be 20% of IC

(b) IB should be 5% of IC

(c) IB should be 10% of IC

(d) IB should be 50% of IC

The question was asked in an interview.

The question is from Stabilization against Variations in VBE and Beta for Self Bias Circuit topic in section Transistor Biasing and Thermal Stabilization of Electronic Devices & Circuits

Answer 1

The correct answer is (c) IB should be 10% of IC

The best explanation: Ideally, the resistor values are designed in a way that the voltage drops across RE is approximately 10% of Vcc and IB should be 10% of Ic. Hence, stable self – bias circuits work best at low power supply voltages.