In a phase-shift control method, the phase shift between anode and grid voltages can be achieved by means of______________?

Related Mcqs:

1. 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 voltage
   B. critical grid voltage
   C. any of the above
   D. none of the above

2. In a grid control of mercury arc rectifiers when the grid is made positive relative to cathode, then it the electrons on their may to anode.

   A. accelerates
   B. decelerates
   C. any of the above
   D. none of the above

3. In phase-shift control method the control is carried out by varying the of grid voltage

   A. magnitude
   B. polarity
   C. phase
   D. any of the above
   E. none of the above

4. In a three-phase mercury arc rectifiers each anode conducts for____________?

   A. one-third of a cycle
   B. one-fourth of a cycle
   C. one-half a cycle
   D. two-third of a cycle

5. The voltage drop between the anode and cathode, of a mercury arc rectifier comprises of the following_____________?

   A. anode drop and cathode drop
   B. anode drop and arc drop
   C. cathode drop and arc drop
   D. anode drop, cathode drop and arc drop

6. The ignited or auxiliary anode in mercury arc rectifier is made of____________?

   A. graphite
   B. boron carbide
   C. aluminium
   D. copper

7. In a mercury arc rectifier, the anode is usually made of_____________?

   A. copper
   B. aluminium
   C. silver
   D. graphite
   E. tungsten

8. In a mercury arc rectifier________ flow from anode to cathode

   A. ions
   B. electrons
   C. ions and electrons
   D. any of the above

9. The voltage drop at anode, in a mercury arc rectifier is due to_____________?

   A. self restoring property of mercury
   B. high ionization potential
   C. energy spent in overcoming the electrostatic field
   D. high temperature inside the rectifier

10. If cathode and anode connections in a mercury arc rectifier are inter changed_____________?

    A. the rectifier will not operate
    B. internal losses will be reduced
    C. both ion and electron streams will move in the same direction
    D. the rectifier will operate at reduced efficiency