Which of the following rectifiers have been used extensively in supplying direct current for electroplating?

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 heating

C

Both (A) and (B)

D

None of the above

The metal rectifiers, as compared to mercury arc rectifiers

A

operate on low temperatures

B

can operate on high voltages

C

can operate on heavy loads

D

give poor regulation

E

none of the above

Which of the following rectifiers are primarily used for charging of low voltage batteries from AC. supply?

A

Mechanical rectifiers

B

Copper oxide rectifiers

C

Selenium rectifiers

D

Electrolytic rectifiers

Mercury, in arc rectifiers, is chosen for cathode because

A

Its ionization potential is relatively low

B

Its atomic weight is quite high

C

Its boiling point and specific heat are low

D

All of the above

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

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

The applications of selenium rectifiers are usually limited to potential of

A

10 V

B

30 V

C

60 V

D

100 V

E

200 V

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

Glass rectifiers are usually made into units capable of D.C. output (maximum continuous rating) of

A

100 A at 100 V

B

200 A at 200 V

C

300 A at 300 V

D

400 A at 400 V

E

500 A at 500 V

In selenium rectifiers efficiencies ranging from ______ to ______ percent are attainable

A

25, 35

B

40, 50

C

60, 70

D

75, 85

Which of the following rectifiers have been used extensively in supplying direct current for electroplating?

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