Power Electronics MCQs (Part-14)

What is the main purpose of a rectifier in a power electronics system?

A To convert DC to AC
B To filter high-frequency noise
C To convert AC to DC
D To step down the voltage

Which semiconductor device is primarily used in high-voltage applications for switching?

A IGBT
B MOSFET
C Diode
D Capacitor

What is the main function of a chopper in a power electronics system?

A To increase frequency
B To convert AC to DC
C To regulate DC motor speed by adjusting voltage
D To filter harmonics

Which type of converter is used to convert DC voltage from one level to another?

A Rectifier
B DC-DC converter
C Cycloconverter
D Inverter

What is Pulse Width Modulation (PWM) commonly used for in power electronics?

A To control the voltage and current to the load
B To increase current levels
C To reduce switching speed
D To step down voltage

What is the primary advantage of using MOSFETs over BJTs in power electronics?

A Higher current carrying capability
B Faster switching speeds and lower power losses
C Lower cost
D Higher voltage breakdown capabilities

Which of the following devices is commonly used to improve power factor in power systems?

A Transformer
B Capacitor
C Inductor
D Diode

What is the role of a gate driver in power electronics systems?

A To control the switching of high-power devices like IGBTs and MOSFETs
B To increase current supply
C To store energy
D To filter harmonics

What is the purpose of a snubber circuit in power electronics?

A To increase voltage
B To store energy
C To absorb voltage spikes during switching events
D To regulate current

In an inverter, what does the DC-AC conversion process involve?

A Converting DC voltage into an alternating waveform
B Filtering harmonics
C Stepping down the voltage
D Increasing current flow

Which of the following is a key factor for increasing energy efficiency in power converters?

A Higher switching frequencies
B Higher voltage levels
C Higher current handling
D Lower switching losses

In power electronics, what is the role of a protection circuit?

A To increase power factor
B To protect components from overvoltage and overcurrent
C To store electrical energy
D To convert DC to AC

What is the main function of a rectifier in a solar power system?

A To step up the voltage
B To convert AC to DC
C To convert DC from the solar panels to a usable form
D To regulate the power factor

Which power electronics device is typically used in high-speed switching applications?

A MOSFET
B BJT
C Thyristor
D Transformer

What is the effect of using higher switching frequencies in power converters?

A Increased size of passive components
B Increased energy losses
C Reduced size of passive components
D Reduced switching speed

What is a common application of DC-AC converters?

A Battery chargers
B Power factor correction
C Motor drives
D Solar power systems

How does a chopper circuit regulate the speed of a DC motor?

A By varying the supply frequency
B By adjusting the DC voltage supplied to the motor
C By converting DC to AC
D By reducing the current to the motor

What does power factor correction improve in an electrical system?

A The voltage levels
B The efficiency of power conversion
C The harmonic content
D The current flow

Which type of converter is used to change the frequency of an AC signal?

A Inverter
B Rectifier
C Cycloconverter
D DC-DC converter

What is the primary purpose of EMI shielding in power electronics systems?

A To increase switching frequency
B To prevent electromagnetic interference from affecting other devices
C To reduce the size of components
D To improve thermal management