# The Alpha Cutoff Frequency MCQ’s

This set of Electronic Devices & Circuits Multiple Choice Questions & Answers (MCQs) focuses on “The Alpha Cutoff Frequency”.

1. How many main types of alpha cutoff frequency are there in bipolar transistors?
a) 3
b) 4
c) 5
d) 6

2. Why do we require RE for a good stable alpha cutoff frequency?
a) To obtain a current IE sensitive to α and VBE
b) To obtain a current IB sensitive to α and VBE
c) To obtain a current IE insensitive to α and VBE
d) To obtain a current IB insensitive to α and VBE

3. What is the function of an alpha cutoff frequency?
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 α = 100. What is the current IE? a) 1.388mA
b) 0.012mA
c) 10.47mA
d) 1.165mA

5. In an ideal stable self – alpha cutoff frequency, what should be the current IBwith 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 during alpha cutoff frequency?
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 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 α would provide maximum stability?
a) VBE = 5V, α = 50
b) VBE = 4V, α = 100
c) VBE = 4.5V, α = 50
d) It is irrelevant

9. Collector base feedback and emitter feedback combined together provide stability for self – alpha cutoff frequency.
a) True
b) False

10. Where does degeneration take place in a self – alpha cutoff frequency?
a) Across RB
b) Across RE
c) No degeneration occurs
d) Across RC