Industrial Electronics – MCQs

1. : What is the primary function of an SCR (Silicon Controlled Rectifier)?
(A) Amplification
(B) Rectification
(C) Switching
(D) Signal generation

2. : Which device is commonly used for speed control in industrial motors?
(A) Diode
(B) Transformer
(C) VFD (Variable Frequency Drive)
(D) Fuse

3. : TRIACs are most commonly used in which type of application?
(A) DC circuits
(B) Light dimming
(C) Amplification
(D) Signal processing

4. : Which semiconductor device can conduct current in both directions when triggered?
(A) Diode
(B) SCR
(C) TRIAC
(D) BJT

5. : What is the function of a PLC (Programmable Logic Controller)?
(A) Data storage
(B) Mechanical control
(C) Automation and control in industrial processes
(D) Voltage regulation

6. : In industrial electronics, what does PWM stand for?
(A) Pulse Width Modulation
(B) Power Wave Motor
(C) Pulse Watt Measurement
(D) Power Width Management

7. : Which of the following is used as a power electronic converter?
(A) MOSFET
(B) Zener diode
(C) Transistor
(D) Resistor

8. : Which component is used to store energy in a magnetic field?
(A) Capacitor
(B) Inductor
(C) Resistor
(D) Diode

9. : The main purpose of an inverter in industrial electronics is to:
(A) Convert AC to DC
(B) Increase voltage
(C) Convert DC to AC
(D) Filter signals

10. : A rectifier is used to:
(A) Filter noise
(B) Convert AC to DC
(C) Amplify signals
(D) Reduce power loss

11. : Which type of protection device is commonly used in industrial circuits?
(A) Diode
(B) Capacitor
(C) Circuit breaker
(D) Oscilloscope

12. : What is the typical application of a solid-state relay (SSR)?
(A) Amplification
(B) Thermal protection
(C) Switching without mechanical contacts
(D) Current measurement

13. : A thyristor is a:
(A) Voltage regulator
(B) Passive component
(C) Power semiconductor switch
(D) Noise filter

14. : What is the primary function of a UPS (Uninterruptible Power Supply)?
(A) Enhance signal strength
(B) Provide backup power
(C) Increase current
(D) Reduce voltage spikes

15. : The device used to change the level of AC voltage is called:
(A) Rectifier
(B) Transformer
(C) Transistor
(D) Inductor

16. : A device that converts electrical energy into mechanical motion is:
(A) Generator
(B) Motor
(C) Transformer
(D) Relay

17. : Which of these is used for overvoltage protection?
(A) Varistor
(B) BJT
(C) Transformer
(D) Capacitor

18. : In industrial automation, SCADA stands for:
(A) System Control And Data Access
(B) Supervisory Control And Data Acquisition
(C) Single Control And Device Arrangement
(D) Sequential Control And Digital Automation

19. : What is the typical function of an opto-isolator?
(A) Signal amplification
(B) Power distribution
(C) Electrical isolation of signals
(D) Voltage regulation

20. : Which of the following is NOT a power electronic device?
(A) IGBT
(B) SCR
(C) TRIAC
(D) LDR

21. : The main application of a DC-DC converter is to:
(A) Change frequency
(B) Convert AC to DC
(C) Step up/down DC voltage
(D) Filter DC voltage

22. : What is the function of a heat sink in industrial electronics?
(A) Store energy
(B) Reduce noise
(C) Dissipate heat
(D) Amplify signals

23. : Which of the following can be used as a high-speed switch?
(A) Inductor
(B) Transistor
(C) Diode
(D) Capacitor

24. : Which is a disadvantage of mechanical relays compared to solid-state relays?
(A) High speed
(B) No noise
(C) Short lifespan
(D) Low cost

25. : Which of the following devices is commonly used to suppress voltage spikes?
(A) Zener diode
(B) MOV (Metal Oxide Varistor)
(C) LED
(D) Inductor