ISCET Electronic Components & Circuit Analysis 2 — Questions and Answers
Question 1: What happens to the total capacitance when capacitors are connected in series?
- Total capacitance increases
- Total capacitance decreases (Correct answer)
- Total capacitance equals the largest capacitor
- Total capacitance remains unchanged
Correct answer: Total capacitance decreases
Capacitors in series have a total capacitance less than the smallest individual capacitor, calculated by the reciprocal sum formula.
Question 2: A zener diode is primarily used in circuits for:
- Signal amplification
- Voltage regulation (Correct answer)
- Frequency filtering
- Current amplification
Correct answer: Voltage regulation
Zener diodes are designed to operate in reverse breakdown to maintain a stable reference voltage.
Question 3: In an RL circuit, the time constant τ is defined as:
- R × C
- L / R (Correct answer)
- R / L
- L × C
Correct answer: L / R
The time constant of an RL circuit is τ = L/R, representing the time for current to reach approximately 63.2% of its final value.
Question 4: Which type of transistor configuration provides the highest voltage gain?
- Common base
- Common emitter (Correct answer)
- Common collector
- Common gate
Correct answer: Common emitter
The common emitter configuration provides the highest voltage gain among the three BJT configurations.
Question 5: A 100 mH inductor carries 2 A of current. What is the energy stored in the inductor?
- 0.1 J
- 0.2 J (Correct answer)
- 0.4 J
- 4 J
Correct answer: 0.2 J
Energy stored in an inductor is W = ½LI² = ½ × 0.1 × 4 = 0.2 J.
Question 6: What is the function of a bypass capacitor in an amplifier circuit?
- Increase DC bias stability
- Short-circuit the emitter resistor at AC frequencies (Correct answer)
- Filter high-frequency noise from the power supply
- Block the DC component of the signal
Correct answer: Short-circuit the emitter resistor at AC frequencies
A bypass capacitor placed across the emitter resistor shorts it at AC frequencies, increasing the AC voltage gain.
Question 7: Which statement correctly describes a depletion-mode MOSFET?
- It requires a positive gate voltage to turn on
- It conducts at zero gate-to-source voltage (Correct answer)
- It is normally off with no gate voltage applied
- It can only operate with N-type channel
Correct answer: It conducts at zero gate-to-source voltage
A depletion-mode MOSFET has a physical channel and is normally on (conducting) when VGS = 0.
ISCET Electronic Components & Circuit Analysis 2
What happens to the total capacitance when capacitors are connected in series?