This set of Electronic Devices & Circuits Multiple Choice Questions & Answers (MCQs) focuses on “Stabilization against Variations in VBE and Beta for Self Bias Circuit”.
1. How many main types of bias circuits are there in bipolar transistors?
2. Why do we require RE for a good stable bias circuit?
a) To obtain a current IE sensitive to β and VBE
b) To obtain a current IB sensitive to β and VBE
c) To obtain a current IE insensitive to β and VBE
d) To obtain a current IB insensitive to β and VBE
3. What is the function of a bias circuit?
a) To simplify the circuit
b) To provide a non – linear output
c) To optimize the power
d) To provide steady current or voltage
4. In the circuit given below, assume VCC = 4V, VBB = 5V, VBE = 0.7V, RE = 3.3kΩ, RC = 10kΩ, RB = 40kΩ and β = 100. What is the current IE?
5. 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
6. What is the stability factor if RE = 8kΩ and RTH = 11kΩ?
7. Why is it essential to stabilize the operating point of a circuit?
a) Thermal runaway, power efficiency, individual variations
b) Temperature dependency of IB, individual variations, power efficiency
c) Thermal runaway, Temperature dependency of IC, individual variations
d) Temperature dependency of IC, thermal runaway, cost efficiency
8. What values of VBE and β would provide maximum stability?
a) VBE = 5V, β = 50
b) VBE = 4V, β = 100
c) VBE = 4.5V, β = 50
d) It is irrelevant
9. Collector base feedback and emitter feedback combined together provide stability for self – bias circuits.
10. Where does degeneration take place in a self – bias circuit?
a) Across RB
b) Across RE
c) No degeneration occurs
d) Across RC