1. The forward bias of a PN junction diode:
(A) Widens the depletion region
(B) Narrows the depletion region
(C) Has no effect on depletion region
(D) Reverses the diode
2. The reverse bias of a PN junction diode:
(A) Narrows the depletion region
(B) Widens the depletion region
(C) Makes the diode conduct heavily
(D) Reduces breakdown voltage
3. The knee voltage (cut-in voltage) of a silicon diode is approximately:
(A) 0.3 V
(B) 0.7 V
(C) 1.0 V
(D) 1.2 V
4. The knee voltage of a germanium diode is approximately:
(A) 0.3 V
(B) 0.7 V
(C) 1.0 V
(D) 1.2 V
5. In the forward-biased region, the diode current:
(A) Increases exponentially with voltage
(B) Remains constant
(C) Decreases with voltage
(D) Becomes zero
6. In the reverse-biased region, the diode current:
(A) Flows freely
(B) Is negligible
(C) Increases exponentially
(D) Is maximum
7. The reverse saturation current in a diode:
(A) Is independent of temperature
(B) Increases with temperature
(C) Decreases with temperature
(D) Is zero
8. The PN junction diode breaks down in reverse bias at:
(A) Forward voltage
(B) Breakdown voltage
(C) Knee voltage
(D) Zero bias
9. Zener diodes operate in:
(A) Forward bias only
(B) Reverse breakdown region
(C) Cutoff region
(D) Saturation region
10. The ideal diode has:
(A) Zero forward voltage drop and infinite reverse resistance
(B) Finite forward voltage drop and zero reverse resistance
(C) Infinite forward voltage drop and zero reverse resistance
(D) Infinite forward and reverse resistance
11. In forward bias, the potential barrier of a PN junction:
(A) Increases
(B) Decreases
(C) Remains constant
(D) Becomes infinite
12. In reverse bias, the potential barrier of a PN junction:
(A) Decreases
(B) Increases
(C) Remains constant
(D) Becomes zero
13. The forward current in a diode is primarily due to:
(A) Minority carriers
(B) Majority carriers
(C) Both carriers equally
(D) Photons
14. The reverse current in a diode is primarily due to:
(A) Majority carriers
(B) Minority carriers
(C) Holes only
(D) Electrons only
15. The I-V characteristic of a PN junction diode is:
(A) Linear in both directions
(B) Exponential in forward, nearly zero in reverse
(C) Linear in forward, exponential in reverse
(D) Zero in forward, linear in reverse
16. The static resistance of a diode is:
(A) Ratio of voltage to current at a point
(B) Derivative of voltage with respect to current
(C) Always zero
(D) Always infinite
17. The dynamic resistance of a diode is:
(A) Ratio of voltage to current at a point
(B) Slope of V-I curve at a point
(C) Always zero
(D) Independent of operating point
18. The maximum current a diode can safely carry is called:
(A) Forward current rating
(B) Reverse saturation current
(C) Peak inverse current
(D) Breakdown current
19. The maximum reverse voltage a diode can withstand without breakdown is called:
(A) Cut-in voltage
(B) Reverse saturation voltage
(C) Peak inverse voltage
(D) Forward voltage
20. In forward bias, the diffusion current:
(A) Dominates
(B) Is negligible
(C) Equal to reverse saturation current
(D) Opposes majority carrier flow
21. In reverse bias, the drift current:
(A) Is dominant
(B) Is negligible
(C) Equal to forward current
(D) Opposes drift of carriers
22. The temperature coefficient of a silicon diode forward voltage is approximately:
(A) +2 mV/°C
(B) 2 mV/°C
(C) +5 mV/°C
(D) 5 mV/°C
23. The temperature coefficient of a germanium diode forward voltage is approximately:
(A) +2 mV/°C
(B) 2 mV/°C
(C) 1.5 mV/°C
(D) 0.5 mV/°C
24. The diode equation expresses current as:
(A) Linear function of voltage
(B) Exponential function of voltage
(C) Constant
(D) Inverse of voltage
25. Minority carrier injection occurs mainly in:
(A) Forward bias
(B) Reverse bias
(C) Cutoff region
(D) Zero bias
26. The forward current of a diode is influenced by:
(A) Doping concentration
(B) Temperature
(C) Applied voltage
(D) All of the above
27. The reverse leakage current is primarily due to:
(A) Thermal generation of carriers
(B) Majority carriers
(C) Forward conduction
(D) Breakdown only
28. The region where the diode conducts heavily under reverse bias is called:
(A) Cutoff
(B) Forward active
(C) Breakdown
(D) Saturation
29. A diode’s V-I characteristic is symmetric for:
(A) Silicon diode
(B) Zener diode
(C) Ideal diode
(D) None of the above
30. In a PN junction diode, the maximum electric field occurs:
(A) In P-region
(B) In N-region
(C) At the junction
(D) At the terminals