SMPS (Switched Mode Power Supplies) MCQs

1. The primary advantage of a Switched Mode Power Supply (SMPS) over a Linear Power Supply is:
A. Higher efficiency
B. Lower cost
C. Higher weight
D. Simpler design

Answer: A. Higher efficiency


2. In a Switched Mode Power Supply, the conversion of AC to DC is achieved through:
A. Rectification
B. Switching
C. Filtering
D. Regulation

Answer: B. Switching


3. Which component in an SMPS is used to store energy during the switching cycle?
A. Resistor
B. Capacitor
C. Transformer
D. Inductor

Answer: D. Inductor


4. The primary function of the switch (usually a transistor) in an SMPS is to:
A. Regulate the output voltage
B. Convert the input AC to DC
C. Store energy for conversion
D. Rapidly switch the input signal on and off

Answer: D. Rapidly switch the input signal on and off


5. In an SMPS, the switching frequency typically ranges from:
A. 50 Hz to 60 Hz
B. 1 kHz to 1 MHz
C. 100 Hz to 1 kHz
D. 10 Hz to 100 Hz

Answer: B. 1 kHz to 1 MHz


6. Which of the following is a type of Switched Mode Power Supply?
A. Buck converter
B. Linear converter
C. Transformer-based rectifier
D. Thyristor-based regulator

Answer: A. Buck converter


7. A buck converter in an SMPS is used to:
A. Step up the input voltage
B. Step down the input voltage
C. Convert DC to AC
D. Convert AC to DC

Answer: B. Step down the input voltage


8. Which type of SMPS is commonly used to step up a low DC voltage to a higher DC voltage?
A. Buck converter
B. Boost converter
C. Buck-boost converter
D. Flyback converter

Answer: B. Boost converter


9. A flyback converter is typically used in SMPS for:
A. High power conversion
B. Low power applications
C. Voltage regulation
D. Signal filtering

Answer: B. Low power applications


10. The term “buck-boost converter” refers to an SMPS that can:
A. Step up or step down the voltage
B. Regulate the output current
C. Filter unwanted noise
D. Only step up the voltage

Answer: A. Step up or step down the voltage


11. In an SMPS, which component typically converts the DC voltage into a high-frequency AC signal?
A. Transformer
B. Rectifier
C. Switch (Transistor)
D. Inductor

Answer: C. Switch (Transistor)


12. The efficiency of an SMPS is primarily determined by:
A. The frequency of the switching
B. The type of filter used
C. The quality of the rectifier
D. The energy losses in the switch and other components

Answer: D. The energy losses in the switch and other components


13. In an SMPS, the purpose of the rectifier stage is to:
A. Filter the output voltage
B. Convert the AC signal to DC
C. Step up or step down the voltage
D. Provide power to the switching device

Answer: B. Convert the AC signal to DC


14. Which of the following is typically used to filter the output voltage in an SMPS?
A. Capacitor
B. Inductor
C. Diode
D. Transformer

Answer: A. Capacitor


15. What is the effect of increasing the switching frequency in an SMPS?
A. Increased efficiency
B. Increased electromagnetic interference (EMI)
C. Lower output voltage
D. Increased power loss

Answer: B. Increased electromagnetic interference (EMI)


16. Switched Mode Power Supplies (SMPS) are commonly used in:
A. Audio amplifiers
B. Power adapters for laptops
C. Power distribution systems
D. All of the above

Answer: D. All of the above


17. Which of the following is a typical application of an SMPS in electronic devices?
A. Voltage regulation in microcontrollers
B. Power supply for motor drives
C. Low-power signal amplification
D. High-frequency signal modulation

Answer: B. Power supply for motor drives


18. SMPS are preferred in battery-powered devices because they:
A. Require fewer components
B. Provide a constant output voltage
C. Have higher efficiency, leading to longer battery life
D. Are cheaper than linear power supplies

Answer: C. Have higher efficiency, leading to longer battery life


19. An important feature of SMPS is that they can:
A. Handle both AC and DC inputs
B. Provide a regulated DC output from an unregulated AC input
C. Work only with DC input
D. Function only at high power levels

Answer: B. Provide a regulated DC output from an unregulated AC input


20. SMPS are often preferred in high-power applications because of their ability to:
A. Use large transformers for voltage conversion
B. Operate at high switching frequencies
C. Provide continuous, unregulated output
D. Require only passive components

Answer: B. Operate at high switching frequencies

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