# Stabilization against Variations in VBE and Beta for Self Bias Circuit MCQ’s

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?

a) 3

b) 4

c) 5

d) 6

2. Why do we require R_{E} for a good stable bias circuit?

a) To obtain a current I_{E} sensitive to β and V_{BE}

b) To obtain a current I_{B} sensitive to β and V_{BE}

c) To obtain a current I_{E} insensitive to β and V_{BE}

d) To obtain a current I_{B} insensitive to β and V_{BE}

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 V_{CC} = 4V, V_{BB} = 5V, V_{BE} = 0.7V, R_{E} = 3.3kΩ, R_{C} = 10kΩ, R_{B} = 40kΩ and β = 100. What is the current I_{E}?

a) 1.388mA

b) 0.012mA

c) 10.47mA

d) 1.165mA

5. In an ideal stable self – bias circuit, what should be the current I_{B} with respect to I_{C}?

a) I_{B} should be 20% of I_{C}

b) I_{B} should be 5% of I_{C}

c) I_{B} should be 10% of I_{C}

d) I_{B} should be 50% of I_{C}

6. What is the stability factor if R_{E} = 8kΩ and R_{TH} = 11kΩ?

a) 1.335

b) 2.375

c) 1.727

d) 0.272

7. Why is it essential to stabilize the operating point of a circuit?

a) Thermal runaway, power efficiency, individual variations

b) Temperature dependency of I_{B}, individual variations, power efficiency

c) Thermal runaway, Temperature dependency of I_{C}, individual variations

d) Temperature dependency of I_{C}, thermal runaway, cost efficiency

8. What values of V_{BE} and β would provide maximum stability?

a) V_{BE} = 5V, β = 50

b) V_{BE} = 4V, β = 100

c) V_{BE} = 4.5V, β = 50

d) It is irrelevant

9. Collector base feedback and emitter feedback combined together provide stability for self – bias circuits.

a) True

b) False

10. Where does degeneration take place in a self – bias circuit?

a) Across R_{B}

b) Across R_{E}

c) No degeneration occurs

d) Across R_{C}