Electronic Devices & Circuits – MCQs

1. : Which of the following is a unidirectional device?
(A) Resistor
(B) Capacitor
(C) Diode
(D) Transformer

2. : What is the main function of a transistor?
(A) Filter signals
(B) Store energy
(C) Amplify or switch electronic signals
(D) Convert AC to DC

3. : In an n-type semiconductor, the majority carriers are:
(A) Holes
(B) Electrons
(C) Ions
(D) Protons

4. : The P-N junction acts as a:
(A) Switch
(B) Filter
(C) Rectifier
(D) Transformer

5. : What is the unit of capacitance?
(A) Ohm
(B) Farad
(C) Volt
(D) Henry

6. : Which device is commonly used to regulate voltage?
(A) BJT
(B) SCR
(C) Zener Diode
(D) FET

7. : The output of a full-wave rectifier is:
(A) Pure AC
(B) DC with ripples
(C) Constant DC
(D) Zero

8. : What is the typical voltage drop across a silicon diode in forward bias?
(A) 0.3V
(B) 0.7V
(C) 1.2V
(D) 2V

9. : Which of the following is a passive component?
(A) Diode
(B) BJT
(C) Inductor
(D) SCR

10. : The cut-off region of a transistor is where:
(A) It acts as an amplifier
(B) Both junctions are forward biased
(C) Both junctions are reverse biased
(D) Base current is high

11. : A common emitter amplifier is known for:
(A) High input impedance
(B) Unity voltage gain
(C) Phase reversal
(D) Negative gain

12. : The main function of a rectifier is to:
(A) Increase current
(B) Change frequency
(C) Convert AC to DC
(D) Convert DC to AC

13. : Which region of the transistor is very lightly doped?
(A) Base
(B) Emitter
(C) Collector
(D) All are equally doped

14. : An SCR is a:
(A) Bipolar device
(B) Unidirectional device
(C) Triode
(D) Bidirectional device

15. : The ideal value of input impedance of an op-amp is:
(A) 0
(B) 1kΩ
(C) 10kΩ
(D) Infinite

16. : In a BJT, current conduction is due to:
(A) Holes only
(B) Electrons only
(C) Both electrons and holes
(D) Ions

17. : What does the Q-point of a transistor represent?
(A) Quality of signal
(B) Quiescent operating point
(C) Charge storage
(D) None of the above

18. : Which configuration of BJT provides the highest power gain?
(A) Common base
(B) Common emitter
(C) Common collector
(D) Emitter follower

19. : The function of a capacitor in a power supply is to:
(A) Increase power
(B) Store charge
(C) Filter out AC ripples
(D) Block DC

20. : The doping level in the emitter of a BJT is:
(A) Light
(B) Moderate
(C) Heavy
(D) Zero

21. : What is the typical input resistance of an op-amp?
22. : The three terminals of a BJT are:
(A) Anode, cathode, gate
(B) Source, gate, drain
(C) Base, collector, emitter
(D) Input, output, ground

23. : Which diode is used for high-frequency applications?
(A) Zener diode
(B) Tunnel diode
(C) Varactor diode
(D) Schottky diode

24. : In a PNP transistor, current flows from:
(A) Emitter to base
(B) Collector to emitter
(C) Base to emitter
(D) Emitter to collector

25. : The transfer characteristic of a transistor shows the relationship between:
(A) Input voltage and output voltage
(B) Output current and input voltage
(C) Output voltage and input current
(D) Collector current and base current