CET Electronic Components and Devices 2 — Questions and Answers
Question 1: What is the primary function of a Zener diode in a circuit?
- Amplify current
- Regulate voltage (Correct answer)
- Store charge
- Emit light
Correct answer: Regulate voltage
A Zener diode is designed to operate in reverse breakdown to maintain a stable reference voltage.
Question 2: Which transistor configuration provides the highest voltage gain?
- Common base
- Common emitter (Correct answer)
- Common collector
- Common drain
Correct answer: Common emitter
The common emitter configuration provides the highest voltage gain among BJT configurations.
Question 3: A capacitor has a capacitance of 100 µF and is charged to 50 V. What is the energy stored?
- 0.125 J (Correct answer)
- 0.25 J
- 2.5 J
- 5.0 J
Correct answer: 0.125 J
Energy stored = ½CV² = ½ × 100×10⁻⁶ × 50² = 0.125 J.
Question 4: What type of semiconductor material is created when silicon is doped with phosphorus?
- P-type
- N-type (Correct answer)
- Intrinsic
- Degenerate
Correct answer: N-type
Phosphorus has five valence electrons, donating an extra electron to silicon and creating N-type material.
Question 5: Which component is used to protect a circuit from reverse polarity connection?
- Varistor
- Series diode (Correct answer)
- Capacitor
- Inductor
Correct answer: Series diode
A series diode blocks current when voltage is applied in reverse polarity, protecting the circuit.
Question 6: An SCR (Silicon Controlled Rectifier) can be turned ON by applying a signal to which terminal?
- Anode
- Cathode
- Gate (Correct answer)
- Base
Correct answer: Gate
A positive gate pulse triggers the SCR into conduction when the anode is positive with respect to the cathode.
Question 7: What is the typical knee voltage for a silicon diode?
- 0.2 V
- 0.3 V
- 0.7 V (Correct answer)
- 1.4 V
Correct answer: 0.7 V
Silicon diodes have a forward knee (threshold) voltage of approximately 0.7 V.
CET Electronic Components and Devices 2
What is the primary function of a Zener diode in a circuit?