In a phase-shift control method, the phase shift between anode and grid voltages can be achieved by means of______________? A. shunt motor B. synchronous motorC. induction regulator D. synchronous generator

In mercury arc rectifiers having grid, the arc can be struck between anode and cathode only when the grid attains a certain potential, this potential being known as______________? A. maximum grid voltageB. critical grid voltage C. any of the above…

Which of the following statement is incorrect ? A. Copper oxide rectifier is a linear device B. Copper oxide rectifier is not a perfect rectifier C. Copper oxide rectifier has a low efficiency D. Copper oxide rectifier finds use in…

In phase-shift control method the control is carried out by varying the of grid voltage A. magnitude B. polarityC. phase D. any of the above E. none of the above

The metal rectifiers are preferred to valve rectifiers due to which of the following advantages ? A. They are mechanically strong B. They do not require any voltage for filament heatingC. Both (A) and (B) D. None of the above

Copper oxide rectifier is usually designed not to operate above___________? A. 10°C B. 20°C C. 30°CD. 45°C

Ageing of a selenium rectifier may change the output voltage by__________? A. 5 to 10 per cent B. 15 to 20 per cent C. 25 to 30 per cent D. none of the above

The efficiency of the copper oxide rectifier seldom exceeds____________? A. 90 to 95% B. 85 to 90% C. 80 to 85%D. 65 to 75%

Selenium rectifier can be operated at temperatures as high as____________? A. 25°C B. 40°C C. 60°CD. 75°C

The applications of selenium rectifiers are usually limited to potential of_____________? A. 10 V B. 30 V C. 60 VD. 100 V E. 200 V