In a full bridge VSI, in order to avoid the short circuit across the DC bus and the undefined AC output voltage condition, the modulating technique should ensure that___________?

A. Top switch of each leg is on at any instant
B. Bottom switch of each leg is on at any instant
C. Either a. or b.
D. None of these

The ac voltage controller can be used for ___________?

A. Lighting and heating control
B. On – line transformer tap changing
C. Soft starting
D. All of these

In a lossless inverter, the average power absorbed in one period by the load must be__________?

A. Equal to the average power supplied by the dc source
B. Greater than the average power supplied by the dc source
C. Lesser than the average power supplied by the dc source
D. Equal to the average power supplied by the ac source

A step – down choppers can be used in___________?

A. Electric traction
B. Electric vehicles
C. Machine tools
D. All of these

The output current in PWM DC – DC converters is equal to___________?

A. Average value of the output inductor current
B. Product of an average inductor current and a function of duty ratio
C. Either a. or b.
D. None of these

The opposite of susceptibility is___________?

A. Immunity
B. Emission
C. Interference
D. Electromagnetic compatibility

The ability of an electronic system to function properly in its intended electromagnetic environment and should not be a source of pollution to that electromagnetic environment is known as____________?

A. Susceptibility
B. Emission
C. Interference
D. Electromagnetic compatibility

If all the SCR’s of 3 phase PAC is replaced by diodes, they would be triggered_____________?

A. 120 degree after the zero crossing of the corresponding line voltages
B. 60 degree after the zero crossing of the corresponding line voltages
C. 120 degree before the zero crossing of the corresponding line voltages
D. 60 degree before the zero crossing of the corresponding line voltages

For commutation in three phase PAC, normally balanced three phase voltages VR, VY and VB are connected to the three legs of the converter via______________?

A. Three inductances
B. Three capacitances
C. Three resistance
D. Three transistors

In square wave operation mode of 3 phase VSI, the VSI

A. Can control the load voltage
B. Cannot control the load voltage
C. Cannot control the load voltage except by means of dc link voltage
D. Cannot control the load voltage except by means of dc link current