semiconductors

Electronic Engineering MCQs

numberonestar Science

Electronics Devices 

1.semiconductors

semiconductors
semiconductors

1. A silicon diode measures a low value of resistance with the meter leads in both positions. The trouble, if any, is
A. the diode is open.
B. the diode is shorted to ground.
C. the diode is internally shorted.
D. the diode is working correctly.
Answer: Option C

2. Single-element semiconductors are characterized by atoms with __ valence electrons.
A. 3
B. 4
C. 5
D. 2
E. none of the above
Answer: Option B

3. Under normal conditions a diode conducts current when it is
A. reverse-biased.
B. forward-biased.
C. avalanched.
D. saturated.
Answer: Option B

4. A diode conducts when it is forward-biased, and the anode is connected to the ____ through a limiting resistor.
A. positive supply
B. negative supply
C. cathode
D. anode
Answer: Option A

5. As the forward current through a silicon diode increases, the internal resistance
A. increases.
B. decreases.
C. remains the same.
Answer: Option B

6. The movement of free electrons in a conductor is called 
A. voltage.
B. current.
C. recombination.
D. equilibrium.
Answer: Option B

7. For a forward-biased diode, the barrier potential ____ as temperature increases.
A. decreases
B. remains constant
C. increases
Answer: Option A

8. The wide end arrow on a schematic indicates the ____ of a diode.
A. ground
B. direction of electron flow
C. cathode
D. anode
Answer: Option D

9. An n-type semiconductor material
A. is intrinsic.
B. has trivalent impurity atoms added.
C. has pentavalent impurity atoms added.
D. requires no doping.
Answer: Option C

10. For a forward-biased diode, as temperature is ___, the forward current ___ for a given value of forward voltage.
A. decreased, increases
B. increased, increases
C. increased, decreases
D. decreased, decreases
Answer: Option B

11. Which statement best describes an insulator?
A. A material with many free electrons.
B. A material doped to have some free electrons.
C. A material with few free electrons.
D. No description fits.
Answer: Option C

12. Effectively, how many valence electrons are there in each atom within a silicon crystal?
A. 2
B. 4
C. 8
D. 16
Answer: Option C

13. The boundary between p-type material and n-type material is called
A. a diode.
B. a reverse-biased diode.
C. a PN junction.
D. a forward-biased diode.
Answer: Option C

14. You have an unknown type of diode in a circuit. You measure the voltage across it and find it to be 0.3 V. The diode might be
A. a silicon diode.
B. a germanium diode.
C. a forward-biased silicon diode.
D. a reverse-biased germanium diode.
Answer: Option B

15. An ideal diode presents a(n) ___ when reversed-biased and a(n) ___ when forward-biased.
A. open, short
B. short, open
C. open, open
D. short, short
Answer: Option A

16. A reverse-biased diode has the ___ connected to the positive side of the source, and the ___ connected to the negative side of the source.
A. cathode, anode
B. cathode, base
C. base, anode
D. anode, cathode
Answer: Option A

17. What types of impurity atoms are added to increase the number of conduction-band electrons in intrinsic silicon?
A. bivalent
B. octavalent
C. pentavalent
D. trivalent
E. none of the above
Answer: Option C

18. What factor(s) do(es) the barrier potential of a PN junction depend on?
A. type of semi-conductive material
B. the amount of doping
C. the temperature
D. all of the above
E. type of semi-conductive material and the amount of doping but not the temperature
Answer: Option D

19. An atom is made up of
A. protons.
B. neutrons.
C. electrons.
D. all of the above
Answer: Option D

20. Reverse breakdown is a condition in which a diode
A. is subjected to a large reverse voltage.
B. is reverse-biased and there is a small leakage current.
C. has no current flowing at all.
D. is heated up by large amounts of current in the forward direction.
Answer: Option A

21. There is a small amount of current across the barrier of a reverse-biased diode. This current is called
A. forward-bias current.
B. reverse breakdown current.
C. conventional current.
D. reverse leakage current.
Answer: Option D

22. As the forward current through a silicon diode increases, the voltage across the diode
A. increases to a 0.7 V maximum.
B. decreases.
C. is relatively constant.
D. decreases and then increases.
Answer: Option C

23. Doping of a semiconductor material means
A. that a glue-type substance is added to hold the material together.
B. that impurities are added to increase the resistance of the material.
C. that impurities are added to decrease the resistance of the material.
D. that all impurities are removed to get pure silicon.
Answer: Option C

24. The forward voltage across a conducting silicon diode is about
A. 0.3 V.
B. 1.7 V.
C. –0.7 V.
D. 0.7 V.
Answer: Option D

25. The most common type of diode failure is a(n) ____.
A. open
B. short
C. restive
Answer: Option A

26. What occurs when a conduction-band electron loses energy and falls back into a hole in the valence band?
A. doping
B. recombination
C. generation
Answer: Option B

27. The maximum number of electrons in each shell of an atom is
A. 2.
B. 2n2 where n is the number of the shell.
C. 4.
D. 8.
Answer: Option B

28. A silicon diode is forward-biased. You measure the voltage to ground from the anode at ___, and the voltage from the cathode to ground at ___.
A. 0 V, 0.3 V
B. 2.3 V, 1.6 V
C. 1.6 V, 2.3 V
D. 0.3 V, 0 V
Answer: Option B

29. The term bias in electronics usually means
A. the value of ac voltage in the signal.
B. the condition of current through a PN junction.
C. the value of dc voltages for the device to operate properly.
D. the status of the diode.
Answer: Option C

2.Semiconductor Diodes

3.Special-Purpose Diodes

4.Diode Applications

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