# Self-Bias MCQ’s

This set of Electronic Devices & Circuits Multiple Choice Questions & Answers (MCQs) focuses on “Self-Bias”.

1. The collector to emitter voltage (VCE) is obtained by_________
a) VCC – RCIC+RBIB
b) VCC – RCIC-REIE
c) VCC + RCIC
d) VCC + RCIB

2. The thermal runway is avoided in a self bias because_________
a) of its independence of β
b) of the positive feedback produced by the emitter resistor
c) of the negative feedback produced by the emitter resistor
d) of its dependence of β

3. The collector current (IC) that is obtained in a self biased transistor is_________
a) (VTH – VBE)/RE
b) (VTH + VBE)/RE
c) (VTH – VBE)/RE
d) (VTH + VBE)/RE

4. 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

5. What is the Thevenin’s resistance (RTH) in a self bias shown below?

a) R1R2/R1+R2
b) R2/R1+R2
c) R1R2/R1-R2
d) R1/R1-R2

6. In the circuit, the transistor has a large β value (VBE=0.7V). Find the current through RC.

a) 0.5mA
b) 2mA
c) 1mA
d) 1.6mA

7. What is the Thevenin’s voltage (VTH) in a self bias shown below?

a) VCCR2/R1+R2
b) VCCR1/R1+R2
c) VCCR2/R1-R2
d) VCCR2/R1-R2

8. The stability factor for a self biased transistor is_________
a) 1 – RTH/RE
b) 1 + RTH/RE
c) 1 + RE/RTH
d) 1 – RE/RTH

9. A silicon NPN transistor is used and it has a large value of β. Find the required value of R2 when IC=1mA.

a) 10kΩ
b) 20kΩ
c) 30kΩ
d) 40kΩ

10. The value of αac for all practical purposes, for commercial transistors range from_________
a) 0.5 to 0.6
b) 0.7 to 0.77
c) 0.8 to 0.88
d) 0.9 to 0.99