# MCQs in Semiconductor Diodes

(Last Updated On: December 8, 2017)

This is the Multiple Choice Questions in Semiconductor Diodes from the book Electronic Devices and Circuit Theory 10th Edition by Robert L. Boylestad. If you are looking for a reviewer in Electronics Engineering this will definitely help. I can assure you that this will be a great help in reviewing the book in preparation for your Board Exam. Make sure to familiarize each and every questions to increase the chance of passing the ECE Board Exam.

### Online Questions and Answers Topic Outline

• MCQs in Ideal Diode
• MCQs in Semiconductor Materials
• MCQs in Energy Levels
• MCQs in Extrinsic Materials—n- and p-Type
• MCQs in Semiconductor Diode
• MCQs in Resistance Levels
• MCQs in Diode Equivalent Circuits
• MCQs in Diode Specification Sheets
• MCQs in Transition and Diffusion Capacitance
• MCQs in Reverse Recovery Time
• MCQs in Semiconductor Diode Notation
• MCQs in Diode Testing
• MCQs in Zener Diodes
• MCQs in Light-Emitting Diodes (LEDs)
• MCQs in Diode Arrays—Integrated Circuits

### Practice Exam Test Questions

Choose the letter of the best answer in each questions.

1. How many terminals does a diode have?

• A) 1
• B) 2
• C) 3
• D) 4

2. What is the resistor value of an ideal diode in the region of conduction?

• A) 0
• B) 5 k
• C) Undefined
• D) Infinity

3. What is the state of an ideal diode in the region of nonconduction?

• A) An open circuit
• B) A short circuit
• C) Unpredictable
• D) Undefined

4.The diode _____.

• A) is the simplest of semiconductor devices
• B) has characteristics that closely match those of a simple switch
• C) is a two-terminal device
• D) All of the above

5.The ideal diode is a(n) _____ circuit in the region of nonconduction.

• A) open
• B) short

6.Which of the following is an atom composed of?

• A) Electrons
• B) Protons
• C) Neutrons
• D) All of the above

7. How many orbiting electrons does the germanium atom have?

• A) 4
• B) 14
• C) 32
• D) 41

8.How many valence electrons does a silicon atom have?

• A) 1
• B) 2
• C) 3
• D) 4

9.One eV is equal to _____ J.

• A) 6.02 × 1023
• B) 1.6 × 10–19
• C) 6.25 × 1018
• D) 1.66 × 10–24

10. Which of the following elements is most frequently used for doping pure Ge or Si?

• A) Boron
• B) Gallium
• C) Indium
• D) All of the above

11.The diffused impurities with _____ valence electrons are called donor atoms.

• A) 4
• B) 3
• C) 5
• D) 0

12.In what state is a silicon diode if the voltage drop across it is about 0.7 V?

• A) No bias
• B) Forward bias
• C) Reverse bias
• D) Zener region

13.What unit is used to represent the level of a diode forward current IF?

• A) pA
• B) nA
• C) A
• D) mA

14.Which of the following ratings is true?

• A) Si diodes have higher PIV and narrower temperature ranges than Ge diodes.
• B) Si diodes have higher PIV and wider temperature ranges than Ge diodes.
• C) Si diodes have lower PIV and narrower temperature ranges than Ge diodes.
• D) Si diodes have lower PIV and wider temperature ranges than Ge diodes.

15.It is not uncommon for a germanium diode with an Is in the order of 1–2 A at 25°C to have leakage current of 0.1 mA at a temperature of 100°C.

• A) True
• B) False

16. Calculate static resistance RD of a diode having ID = 30 mA and VD = 0.75 V.

• A) 25
• B) 40
• C) 0.04
• D) 0.025

17. Calculate ID if RD = 30 and VD = 0.84 V.

• A) 28 mA
• B) 0.028 mA
• C) 2.8 A
• D) 280 A

18. Refer to Figure 1.27. Calculate the dynamic resistance rd of a diode having ID = 27.5 mA.

• A) 0
• B) 2
• C) 5
• D) 26

19. Determining rd to a high degree of accuracy from a characteristic curve is very accurate.

• A) True
• B) False

20. The _____ diode model is employed most frequently in the analysis of electronic systems.

• A) ideal device
• B) simplified
• C) piecewise-linear

21.Calculate the power dissipation of a diode having ID = 40 mA.

• A) 28 mW
• B) 28 W
• C) 280 mW
• D) Undefined

22. Which capacitance dominates in the reverse-bias region?

• A) depletion
• B) conversion
• C) 40 Diffusion
• D) 140 None of the above

23. Which capacitance dominates in the forward-bias region?

• A) Diffusion
• B) Transition
• C) Depletion
• D) None of the above

24. At what kind of operating frequency diffusion or transition is a capacitor represented in parallel with the ideal diode?

• A) Low frequency
• B) Moderate frequency
• C) Mid frequency
• D) Very high frequency

25. What is the value of the transition capacitance for a silicon diode when VD = 0?

• A) 1 pF
• B) 3 pF
• C) 5 pF
• D) 10 pF

26. Which of the following devices can check the condition of a semiconductor diode?

• A) Digital display meter (DDM)
• B) Multimeter
• C) Curve tracer
• D) All of the above

27. What does a high resistance reading in both forward- and reverse-bias directions indicate?

• A) A good diode
• B) An open diode
• C) A shorted diode
• D) A defective ohmmeter

28. The condition of a semiconductor diode can be determined quickly using a _____.

• A) DDM
• B) VOM
• C) curve tracer
• D) Any of the above

29. Determine the nominal voltage for the Zener diode at a temperature of 120° C if the nominal voltage is 5.1 volts at 25° C and the temperature coefficient is 0.05%/° C.

• A) 4.6 V
• B) 4.86 V
• C) 5.1 V
• D) 5.34 V

30. Calculate the temperature coefficient in %/° C of a 10-V nominal Zener diode at 25° C if the nominal voltage is 10.2 V at 100° C.

• A) 0.0238
• B) 0.0251
• C) 0.0267
• D) 0.0321

31. In which of the following color(s) is (are) LEDs presently available?

• A) Yellow
• B) White
• C) Orange
• D) All of the above

32.What is the maximum power rating for LEDs?

• A) 150 mW
• B) 500 mW
• C) 1 W
• D) 10 W

33. In which of the following is the light intensity measured?

• A) Candela
• B) Efficacy
• C) Flux
• D) Illumination

34. What is the range of the operating voltage level for LEDs?

• A) 5–12 mV
• B) 1.7–3.3 V
• C) 5–12 V
• D) 20–25 V

35. In general, LEDs operate at voltage levels from _____ V to _____ V.

• A) 1.0, 3.0
• B) 1.7, 3.3
• C) 0.5, 4.0
• D) None of the above

### FILL IN THE BLANK QUESTIONS

1. A(n) _____ is the simplest of semiconductor devices.

• A) diode
• B) transistor
• C) operational amplifier
• D) SCR

2. The term _____ is often used when comparing the resistance level of materials.

• A) permittivity
• B) inductivity
• C) conductivity
• D) resistivity

3. In the atomic lattice the _____ and _____ form the nucleus.

• A) electrons, neutrons
• B) electrons, protons
• C) neutrons, protons
• D) None of the above

4. An increase in temperature of a semiconductor can result in a _____ in the number of free electrons in the material.

• A) substantial increase
• B) substantial decrease
• C) slight decrease
• D) no change

5. Ge and Si have a(n) _____ coefficient in forward bias.

• A) positive temperature
• B) negative temperature
• C) absolute temperature
• D) temperature free

6. Any electron that has left its parent atom has _____ energy state relative to any electron in the atomic structure.

• A) the same
• B) a lower
• C) a higher
• D) an undefined

7. Introducing those impurity elements that have _____ valence electrons creates the n-type material.

• A) 0
• B) 3
• C) 4
• D) 5

8. In n-type material the _____ is called the majority carrier.

• A) electron
• B) hole
• C) proton
• D) neutron

9. The diffused impurities with _____ valence electrons are called acceptor atoms.

• A) 0
• B) 3
• C) 4
• D) 5

10. The reverse-saturation current level is typically measured in _____.

• A) pA
• B) µA
• C) mA
• D) A

11. The depletion width _____ in the forward bias, which results in having a majority flow across the junction.

• A) widens
• B) remains unchanged
• C) shrinks
• D) widens and shrinks alternatively

12. The forward characteristics curve of a diode grows in _____ form.

• A) linear
• B) exponential
• C) logarithmic
• D) sinusoidal

13. The potential at which the characteristics curve vertical rise occurs is commonly referred to as the _____.

• A) offset
• B) threshold
• C) firing potential
• D) All of the above

14. The reverse saturation current Is will just _____ in magnitude for every 10° C increase in temperature.

• A) double
• B) remain the same
• C) halve
• D) triple

15. Diodes are connected _____ to increase the current-carrying capacity.

• A) in series
• B) in parallel
• C) in parallel-series
• D) None of the above

16. The _____ the current through a diode, the _____ the dc resistance level.

• A) higher, lower
• B) lower, lower
• C) lower, higher
• D) higher, higher

17. Varying the _____ can control the location of the Zener region.

• A) forward current
• B) doping levels
• C) forward voltage
• D) dc resistance

18. The test current in a Zener diode IZT is the current defined by the _____ power level.

• A) 0.25
• B) 0.5
• C) 0.75
• D) 1.00

19. The heavier the current in a Zener diode in reverse bias, _____ dynamic resistance value.

• A) the more the
• B) the less the
• C) there is substantially more
• D) there is no change in the

20. The intensity of LED is greatest at _____ degrees and the least at _____ degrees.

• A) 0, 90
• B) 45, 90
• C) 0, 45
• D) 90, 180

21. The temperature coefficient can be _____ for different Zener levels.

• A) positive
• B) negative
• C) zero
• D) All of the above

22. The reverse recovery time of most commercial switching diodes is in the range of _____.

• A) picoseconds
• B) a few nanoseconds
• C) several microseconds
• D) milliseconds

23. The ac resistance of a diode is the _____ of the characteristic curve at the Q-point of operation.

• A) reciprocal of the slope
• B) slope
• C) midpoint
• D) average value

24. Generally the value of ac resistance is _____ the value of dc resistance at the same operating point.

• A) smaller than
• B) larger than
• C) the same as
• D) unrelated to

25. The reverse-bias current _____ with the increase of temperature.

• A) decreases
• B) increases
• C) remains the same
• D) None of the above