70 practice sets · Page 2 of 4
The square wave operation of 3 phase VSI lines contains the harmonics. The amplitudes are
Inversely proportional to their harmonic order
Not related to their harmonic order
Directly proportional to their harmonic order
None of these
The power MOSFET device is a
Voltage controlled unipolar device
Current controlled bipolar device
Current controlled unipolar device
Voltage controlled bipolar device
The output power of the cascaded amplifier-attenuator system can be determined using
Actual gain of amplifier and attenuator
Gain in dB of amplifier and attenuator
Actual gain of amplifier
Actual gain of attenuator
The normal way to turn on a diac is by ...........................
Gate voltage
Breakover voltage
Gate current
None of the above
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 train of pulses
Continuous signal
None of these
The input current waveform of a bridge controlled rectifier when the load is perfectly filtered is
Square wave
Saw - tooth wave
Sine wave
Trapezoidal wave
The effects of EMI can be reduced by
Suppressing emissions
All of these
Reducing the efficiency of the coupling path
Reducing the susceptibility of the receptor
The device that exhibits negative resistance region is .........................
Diac
UJT
Triac
Transistor
The device that does not have the gate terminal is ............................
Triac
Diac
FET
SCR
The conduction losses in IGBT is
More than that of MOSFET
Equal to that of BJT
Lower than that of MOSFET
Equal to that of MOSFET
Single phase VSI are mainly used in
Power supplies
All of these
Ups
Multilevel configuration
Silicon controlled rectifier can be turned on
By applying a gate pulse and turned off only when current becomes zero
By making current non zero and turned off by making current zero
And turned off by applying gate pulse
By applying a gate pulse and turned off by removing the gate pulse
Power electronics essentially deals with control of a.c. power at .....................
Frequencies above 20 kHz
50 Hz frequency
Frequencies above 1000 kHz
Frequencies less than 10 Hz
LISN is a device used to measure conducted emissions. LISN stands for
Line integrated stabilization network
Laser integrated stabilization networking
Line impedance stabilization network
Line integrated stored network
In single phase VSI, the harmonic which is not present is
2nd
7th
3rd
5th
In radiative coupling, the emitter radiation field
Decays as 1 / R, where R is the separation distance between the emitter and the receptor
Decays as 2R, where R is the separation distance between the emitter and the receptor
Decays as R, where R is the separation distance between the emitter and the receptor
Decays as 1 / 2 R, where R is the separation distance between the emitter and the receptor
In EMCsignal, the source delivers maximum power to the input of transmissionline when the transmission line input impedance
Is equal to the source resistance
None of these
Greater than the source resistance
Smaller than the source resistance
In current commutated DC - DC choppers, the voltage spike appears across the load when
Voltage across the commutating inductances collapses
None of these
The capacitance voltage adds to the supply voltage
Both (a and b)
In bipolar modulation, the carrier is symmetric about zero with amplitude equal to Cm, the PWM output
Zero
Switches between 0 and +1
Switches between -1 / 2 and +1 / 2
Switches between -1 and +1
In a UJT, the p-type emitter is ........................ doped
Lightly
None of the above
Heavily
Moderately
