Due to non sinusoidal waveform of the input current, the power factor of the rectifier is____________?

Negatively affected by firing angle

Negatively affected by distortion of the input current

Positively affected by both firing angle and distortion of the input current

In bipolar modulation, the carrier is symmetric about zero with amplitude equal to Cm, the PWM output

Switches between – 1 / 2 and + 1 / 2

A Triac is a ______________?

3 terminal bidirectional switch

A thyristor equivalent of a thyratron tube is a _________?

Silicon controlled-rectifier SCR

The most suited gate pulses given to the AC regulator with R – L load can be in the form of____________?

Large isolating pulse transformer

A thyristor is basically________?

A combination of diac and triac

An SCR is considered to be a semi controlled device because_______?

it can be turned ON only during one half cycle of an AC

it can be turned OFF but not ON with a gate pulse

it conducts only during one half cycle of an alternating current wave

it can be turned ON but not OFF with a gate pulse

it can be turned ON only during one half cycle of an AC

Transformer utilization factor is a measure of the merit of a rectifier circuit. It is the ratio of_______________?

DC output power to the transformer volt – amp rating required by primary

AC input power to the transformer volt – amp rating required by secondary

AC input power to the transformer volt – amp rating required by primary

DC output power to the transformer volt – amp rating required by secondary

DC output power to the transformer volt – amp rating required by primary

217 + Mcqs in Power Electronics Mcqs in Electrical Engineering Questions Page 5 McqOptions

201.	Due to non sinusoidal waveform of the input current, the power factor of the rectifier is____________?
A.	Negatively affected by firing angle
B.	Negatively affected by distortion of the input current
C.	Positively affected by both firing angle and distortion of the input current
D.	Both (a) and (b)
Answer» E.

Discussion

202.	In bipolar modulation, the carrier is symmetric about zero with amplitude equal to Cm, the PWM output
A.	Zero
B.	Switches between – 1 / 2 and + 1 / 2
C.	Switches between – 1 and + 1
D.	Switches between 0 and + 1
Answer» C. Switches between – 1 and + 1

Discussion

203.	A Triac is a ______________?
A.	2 terminal switch
B.	2 terminal bilateral switch
C.	3 terminal bilateral switch
D.	3 terminal bidirectional switch
Answer» E.

Discussion

204.	A thyristor equivalent of a thyratron tube is a _________?
A.	Diac
B.	Triac
C.	Silicon controlled-rectifier SCR
D.	None of above
Answer» D. None of above

Discussion

205.	Under normal operating condition voltage clamping device offers impedance of_________?
A.	high value
B.	low value
C.	zero value
D.	moderate value
Answer» B. low value

Discussion

206.	The most suited gate pulses given to the AC regulator with R – L load can be in the form of____________?
A.	Continuous signal
B.	Large isolating pulse transformer
C.	A train of pulses
D.	None of these
Answer» D. None of these

Discussion

207.	A silicon controlled racitifier (SCR) is a ____________?
A.	Unijunction device
B.	Device with three junction
C.	Device with four junction
D.	None of the above
Answer» C. Device with four junction

Discussion

208.	A thyristor is basically________?
A.	PNPN device
B.	A combination of diac and triac
C.	A set of SCRs
D.	A set if SCR,diac and triac
Answer» B. A combination of diac and triac

Discussion

209.	If the firing angle becomes negative, then the rectifier begins to work as_______________?
A.	A rectifier
B.	An inverter
C.	A chopper
D.	A regulator
Answer» C. A chopper

Discussion

210.	Thyristor can be protected from over voltages by using____________?
A.	voltage clamping device
B.	fuse
C.	heat sink
D.	snubber circuit
Answer» B. fuse

Discussion

211.	An SCR is considered to be a semi controlled device because_______?
A.	it can be turned OFF but not ON with a gate pulse
B.	it conducts only during one half cycle of an alternating current wave
C.	it can be turned ON but not OFF with a gate pulse
D.	it can be turned ON only during one half cycle of an AC
Answer» D. it can be turned ON only during one half cycle of an AC

Discussion

212.	In constant frequency PWM, at perturbation the amplitude of the sinusoidal component is a___________?
A.	Linear function
B.	Non linear function
C.	Constant function
D.	None of these
Answer» E.

Discussion

213.	In a 3 phase half wave rectifier, when firing angle is less than 90 degree, then the average dc output voltage becomes__________________?
A.	Positive
B.	Negative
C.	Zero
D.	None of these
Answer» B. Negative

Discussion

214.	Transformer utilization factor is a measure of the merit of a rectifier circuit. It is the ratio of_______________?
A.	AC input power to the transformer volt – amp rating required by secondary
B.	AC input power to the transformer volt – amp rating required by primary
C.	DC output power to the transformer volt – amp rating required by secondary
D.	DC output power to the transformer volt – amp rating required by primary
Answer» D. DC output power to the transformer volt – amp rating required by primary

Discussion

215.	A single phase full bridge inverter can operate in load commutation mode in case load consists of____________?
A.	RL
B.	RLC underdamped
C.	RLC overdamped
D.	RLC critically damped
Answer» C. RLC overdamped

Discussion

216.	Thyristor can be protected from over voltages by using
A.	23 mA
B.	40 mA
C.	10 mA
D.	60 mA
Answer» D. 60 mA

Discussion

217.	A single phase one pulse controlled circuit has a resistance R and counter emf E load 400 sin(314 t) as the source voltage. For a load counter emf of 200 V, the range of firing angle control is _____?
A.	30° to 150°.
B.	30° to 180°.
C.	60° to 120°.
D.	60° to 180°.
Answer» B. 30° to 180°.

Discussion

Explore topic-wise MCQs in Electrical Engineering Questions.

Due to non sinusoidal waveform of the input current, the power factor of the rectifier is____________?

In bipolar modulation, the carrier is symmetric about zero with amplitude equal to Cm, the PWM output

A Triac is a ______________?

A thyristor equivalent of a thyratron tube is a _________?

Under normal operating condition voltage clamping device offers impedance of_________?

The most suited gate pulses given to the AC regulator with R – L load can be in the form of____________?

A silicon controlled racitifier (SCR) is a ____________?

A thyristor is basically________?

If the firing angle becomes negative, then the rectifier begins to work as_______________?

Thyristor can be protected from over voltages by using____________?

An SCR is considered to be a semi controlled device because_______?

In constant frequency PWM, at perturbation the amplitude of the sinusoidal component is a___________?

In a 3 phase half wave rectifier, when firing angle is less than 90 degree, then the average dc output voltage becomes__________________?

Transformer utilization factor is a measure of the merit of a rectifier circuit. It is the ratio of_______________?

A single phase full bridge inverter can operate in load commutation mode in case load consists of____________?

Thyristor can be protected from over voltages by using

A single phase one pulse controlled circuit has a resistance R and counter emf E load 400 sin(314 t) as the source voltage. For a load counter emf of 200 V, the range of firing angle control is _____?