All Free Electrical Engineering MCQs with Answers
Every Electrical Engineering question in the bank, across all chapters, each with the correct answer and a written explanation. Free and unlimited, with no account needed.
3,143 questions · page 92 of 158
- A. 6 mA
- B. mA
- C. 3 mA
- D. 1 mA
Explanation: To allow a 3 mA signal swing without driving the transistor into cutoff, the zero-signal collector current must be at least 3 mA.
Correct answer: 3 mA- A. Base resistor bias
- B. Collector feedback bias
- C. Potential divider bias
- D. None of the above
Explanation: Potential-divider bias provides the best common stabilisation because the divider fixes the base voltage and makes the operating point…
Correct answer: Potential divider bias- A. Biasing circuit
- B. Bias battery
- C. Diode
- D. None of the above
Explanation: Transistor biasing is normally established using a biasing circuit containing suitable resistors and a supply arrangement.
Correct answer: Biasing circuit- A. Proper direct current
- B. Proper alternating current
- C. The base current small
- D. Collector current small
Explanation: Biasing establishes the transistor’s required quiescent or zero-signal DC currents and voltages so the signal can be amplified without…
Correct answer: Proper direct current- A. Be zero
- B. Be 0.01 V
- C. Not fall below 0.7 V
- D. Be between 0 V and 0.1 V
Explanation: A silicon base-emitter junction needs about 0.7 V forward bias to conduct properly in the active region.
Correct answer: Not fall below 0.7 V1826. The zero signal IC is generally ______________ mA in the initial stages of a transistor amplifier?
- A. 4
- B. 1
- C. 3
- D. More than 10
Explanation: Small-signal amplifier stages commonly use a quiescent collector current of about 1 mA, providing suitable amplification while keeping…
Correct answer: 1- A. Operating point
- B. Current gain
- C. Voltage gain
- D. None of the above
Explanation: The intersection of the DC load line and AC load line gives the quiescent operating point, also called the Q-point.
Correct answer: Operating point- A. Not fall below 1 V
- B. Be zero
- C. Be 0.2 V
- D. None of the above
Explanation: Keeping VCE above approximately 1 V prevents the transistor from entering saturation during signal variations, allowing faithful…
Correct answer: Not fall below 1 V- A. Values of IC and VCE when signal is applied
- B. The magnitude of signal
- C. Zero signal values of IC and VCE
- D. None of the above
Explanation: The operating point is defined by the quiescent, or zero-signal, values of collector current IC and collector-emitter voltage VCE.
Correct answer: Zero signal values of IC and VCE- A. a.c
- B. d.c
- C. both a.c. and d.c
- D. none of the above
Explanation: Transistor biasing sets the DC voltages and currents that establish the operating point.
Correct answer: d.c- A. Proper forward bias
- B. Proper reverse bias
- C. Very small size
- D. None of the above
Explanation: For a transistor to operate in the active region, its collector-base junction must be reverse biased.
Correct answer: Proper reverse bias- A. Decrease in the base current
- B. Unfaithful amplification
- C. Excessive collector bias
- D. None of the above
Explanation: Without biasing, the transistor may remain in cutoff or enter saturation during part of the signal cycle, causing distortion.
Correct answer: Unfaithful amplification- A. A few free electrons
- B. Many holes
- C. Many free electrons
- D. No holes or free electrons
Explanation: At absolute zero, thermal energy is insufficient to create electron-hole pairs in an ideal intrinsic semiconductor.
Correct answer: No holes or free electrons- A. O
- B. kO
- C. MO
- D. None of the above
Explanation: A reverse-biased junction permits only a tiny leakage current, so its opposition to current is very high, typically of the order of…
Correct answer: MO- A. Very narrow depletion layer
- B. Almost no current
- C. Very low resistance
- D. Large current flow
Explanation: Reverse bias widens the depletion region and strongly restricts majority-carrier flow, leaving only a very small leakage current.
Correct answer: Almost no current- A. 5 V
- B. 3 V
- C. Zero
- D. 0.3 V
Explanation: The barrier voltage of a silicon junction is about 0.7 V, while germanium has the lower value of approximately 0.3 V.
Correct answer: 0.3 V1837. The random motion of holes and free electrons due to thermal agitation is called______________?
- A. Diffusion
- B. Pressure
- C. Ionisation
- D. None of the above
Explanation: Thermal agitation gives carriers random motion, and their net movement from a region of higher concentration to lower concentration is…
Correct answer: Diffusion- A. Repel each other
- B. Attract each other
- C. Have no effect on each other
- D. None of the above
Explanation: An electron carries negative charge and a hole behaves as a positive charge, so their electrostatic force is attractive.
Correct answer: Attract each other- A. +ve terminal to p and -ve terminal to n
- B. -ve terminal to p and +ve terminal to n
- C. -ve terminal to p and -ve terminal to n
- D. None of the above
Explanation: Forward bias connects the positive terminal to the p-side and the negative terminal to the n-side, reducing the depletion barrier.
Correct answer: +ve terminal to p and -ve terminal to n- A. Acceptor ions
- B. Holes and electrons
- C. Donor ions
- D. None of the above
Explanation: Near the junction, electrons and holes recombine, leaving a depletion region almost free of mobile carriers.
Correct answer: Holes and electrons