Question

A common transistor radio set requires 12 V (D.C.) for its operation. The D.C. source is constructed by using a transformer and a rectifier circuit, which are operated at 220 V (A.C.) on standard domestic A.C. supply. The number of turns of secondary coil are 24, then the number of turns of primary are ______.

Options

• 450

• 440

• 430

• 460

Answer 1

A common transistor radio set requires 12 V (D.C.) for its operation. The D.C. source is constructed by using a transformer and a rectifier circuit, which are operated at 220 V (A.C.) on standard domestic A.C. supply. The number of turns of secondary coil are 24, then the number of turns of primary are 440.

Explanation:

Given,

Primary voltage (V_p) = 220 V

Secondary voltage (V₅) = 12 V

Number of turns in secondary coil (N_s) = 24

Number of turns in primary coil (N_p) = ?

For the transformer ratio

`"N"_"p"/"N"_"s" = "V"_"p"/"V"_"s"`

N_p = `"V"_"p"/"V"_"s"xx"N"_"s"`

N_p = `(220xx24)/12`

= 440