MCQ in Electronic Systems and Design Part 1 | ECE Board Exam

This is the Multiple Choice Questions in Electronic Systems and Design Part 1 of the Series as one of the Electronics Engineering Examination topic. In Preparation for the ECE Board Exam make sure to expose yourself and familiarize in each and every questions compiled here taken from various sources including but not limited to past Board Exam Questions in Electronics Engineering field, Electronics Books, Journals and other Electronics References.

MCQ Topic Outline included in ECE Board Exam Syllabi

6. Electronic Systems and Design

• MCQ in SCR’s, UJT, PUT, TRIAC, DIAC, and other Thyristors
• MCQ in Optoelectronic Devices and Sensors
• MCQ in Transducers, Data Acquisition, and Interfacing Techniques
• MCQ in Programmable Logic Controllers
• MCQ in Design and Integration in Building Management Systems and HVAC Controls,
  Security, Safety, and Surveillance Control Systems, and Audio-Video and Lighting
  Controls
• MCQ in Instrumentation and Control
• MCQ in Welding Systems
• MCQ in Robotic Principles
• MCQ in Bioelectrical Principles

Start Practice Exam Test Questions Part 1 of the Series

Choose the letter of the best answer in each questions.

1. What is a nucleonic sensing method employing usually one or more radioisotope sources and radiation detectors?

A. Radiation sensing

B. Sonic level sensing

C. Conductivity level sensing

D. Dielectric variation sensing

2. What is concerned with the measurement of electric signals on the scalp with arise from the underlying neural activity in the brain (including synaptic sources)?

A. ECG

B. EEG

C. Ultrasound

D. EKG

3. In therapeutic radiology and in nuclear medicine, the energies of interest range from about

A. 10 to 100 KeV

B. 100 to 10000 KeV

C. 10000 to 10000 KeV

D. 1 to 10 KeV

4. Which of the following is a four-layer diode with an anode gate and a cathode gate?

A. SCS

B. SCR

C. SBS

D. SUS

5. What is basically a two-terminal parallel-inverse combination of semiconductor layers that permits triggering in either direction?

A. Diac

B. Triac

C. Quadrac

D. Shockley Diode

6. What is the typical value of the interbase resistance of UJTs?

A. 20 KΩ

B. Between 4 to 4 KΩ

C. 4 KΩ

D. Between 4 to 10 KΩ

7. PUT stands for

A. Programmable Unijunction Transistor

B. Programmable Universal Transistor

C. Pulse Unijunction Transistor

D. Pulse Universal Transistor

8. Which transistor conducts current in both directions when turned on?

A. Diac

B. SCR

C. Quadrac

D. SCS

9. What is a three terminal device used to control large current to a load?

A. SCR

B. SCS

C. GTO

D. Thyristor

10. What is the other term for thermoelectric effect?

A. Seebeck effect

B. Hall effect

C. Photoelectric effect

D. Thermal effect

11. What are the regions corresponding to open-circuit condition for the controlled rectifier which block the flow of charge from anode to cathode?

A. Forward blocking regions

B. Reverse blocking regions

C. Breakdown regions

D. Both A and B above

12. The V-I characteristics for a triac in the first and third quadrants are essentially identical to those of ________ in the quotation.

A. SCR

B. UJT

C. Transistor

D. SCS

13. When the temperature increases, the inter-base resistance of a UJT

A. Remains unchanged

B. Increases

C. Decreases

D. is zero

14. The three terminals of a triac are

A. drain, source, gate

B. two main terminals and a gate terminal

C. cathode, anode and gate

D. anode, source, gate

15. A triac is equivalent to two SCRs

A. in parallel

B. in inverse-parallel

C. in series

D. in inverse-series

16. In diagnostic radiology and for superficial therapy purposes, the energy spectrum of radiation varies from about

A. 1 to 10 KeV

B. 10 to 100 KeV

C. 100 to 10000 KeV

D. 10000 to 100000 KeV

17. The x-ray region of the electromagnetic spectrum has a corresponding range of wavelengths from

A. 0.1 to 0.0001 nm

B. 0.1 to 0.0001 pm

C. 0.1 to 0.0001 μm

D. 0.1 to 0.0001 mm

18. The three terminals of an SCR are the

A. anode, cathode, and grid

B. cathode, anode, gate

C. anode, cathode, drain

D. drain, source, gate

19. If a body is considered as a conducting sphere of 0.5m radius its capacitance to infinity is

A. 55 pF

B. 55 nF

C. 55 μF

D. 55 F

20. How many semiconductor layers does an SCR have?

A. Four

B. Two

C. Three

D. Five

21. A triac is a _______ switch.

A. unidirectional

B. mechanical

C. bidirectional

D. omnidirectional

22. Which of the following is the normal way to turn on an SCR?

A. By breakover voltage

B. By appropriate anode current

C. By appropriate cathode current

D. By appropriate gate current

23. A triac can pass a portion of ________ half cycle through the load

A. only positive

B. only negative

C. both positive and negative

D. neither positive nor negative

24. A diac has how many terminals?

A. Two

B. Three

C. Four

D. Five

25. An SCR combines the feature of

A. a rectifier and resistance

B. a rectifier and capacitor

C. a rectifier and transistor

D. a rectifier and inductor

26. Which is the control element in an SCR?

A. Anode

B. Cathode

C. Gate

D. Cathode supply

27. How many semiconductor layers does a triac have?

A. Two

B. Four

C. Three

D. One

28. A diac has how many semiconductor layers?

A. Three

B. Four

C. Two

D. Five

29. The p-type emitter of a UJT is _______ doped.

A. lightly

B. moderately

C. heavily

D. not

30. A diac has

A. one pn junction

B. three pn junctions

C. two pn junctions

D. four pn junctions

31. A UJT is sometimes called a _______ diode.

A. double-based

B. single-based

C. a rectifier

D. a switching diode

32. A diac is _______ switch.

A. an AC

B. a mechanical

C. a dc

D. both ac and dc

33. An SCR is made of silicon and not germanium because silicon.

A. is inexpensive

B. has low leakage current

C. is mechanically strong

D. is tetravalent

34. What is the control element in an SCR?

A. Gate

B. Anode

C. Grid

D. Cathode

35. An effect that reduces the possibility of accidental triggering of the SCS.

A. Miller effect

B. Rate effect

C. End effect

D. Flywheel effect

36. Which of the following is a common application of UJT?

A. Amplifier

B. Rectifier

C. Mulitivibrator

D. Sawtooth generator

37. Which device does not have a gate terminal?

A. Triac

B. SCR

C. FET

D. Diac

38. An SCR is a _______ triggered device.

A. current

B. power

C. voltage

D. noise

39. When UJTs is turned on, the resistance between emitter terminal and lower base terminal

A. remains unchanged

B. increases

C. decreases

D. becomes zero

40. The UJT has

A. two pn junctions

B. three pn junctions

C. one pn junction

D. four on junction

41. The UJT may be used as

A. an amplifier

B. a rectifier

C. a sawtooth generator

D. a multivibrator

42. Which of the following is the normal way to turn on a diac?

A. By breakover voltage

B. By gate voltage

C. By gate current

D. By anode current

43. Power electronics deals with the control of ac power at what frequencies essentially?

A. 20 KHz

B. 1000 KHz

C. Frequencies less than 10 Hz

D. 60 Hz frequency

44. When the emitter terminal of a UJT is open, the resistance between the base-terminals is generally

A. low

B. extremely low

C. high

D. extremely high

45. AC power in a load can be controlled by connecting

A. two SCRs in series

B. two SCRs in parallel

C. two SCRs in parallel opposition

D. two SCRs in series opposition

46. Which equation defines the intrinsic stand off ratio (η) of UJTs?

A. RB1 / (RB1 + RB2)

B. (RB1 + RB2) / RB1

C. (RB1 + RB2) / RB2

D. RB1 + RB2

47. To turn off the SCR, which of the following is done?

A. Reduce gate voltage to zero

B. Reverse bias the gate

C. Reduce anode voltage to zero

D. Reduce cathode voltage to zero

48. Control system that maintains a speed voltage, or other variable within specified limits of a preset level.

A. Controller

B. Regulator

C. Sensor

D. Computer

49. To turn on the UJT, the forward bias on emitter diode should be ________ the peak point voltage.

A. more than

B. less than

C. equal to

D. twice

50. When the temperature increases, the intrinsic stand off ratio

A. increases

B. decreases

C. essentially constant

D. becomes zero

Questions and Answers in Electronic Systems and Design

Following is the list of multiple choice questions in this brand new series:

Complete List of MCQ in Electronics Engineering per topic