Question

A disk drive plugged into a 120V outlet operates on a voltage of 12V . The transformer that powers the disk drive has 125 turns on its primary coil.
Part A) Should the number of turns on the secondary coil be greater than or less than 125? greater than or less than
Part B) Explain
Part C) Find the number of turns on the secondary coil.

Answer 1

Answer:

(A-) Number of turns in secondary coil will be less than 125.

(B-) EXPLAIN- The voltage is to be lowered. The voltage will be reduced from 120 to 9 volts. As a result, a step down transformer will be used, indicating that the secondary coil's number of turns would be less than 125.

(C-) The number of turns on the secondary coil is 12.5

Explanation:

• STEP DOWN TRANSFORMER - A step-down transformer transforms high voltage (HV) and low current from the transformer's primary side to low voltage (LV) and high current on the secondary side. A phase down transformer is the opposite of this.

In electrical networks and transmission lines, a step-down transformer can be used in a number of ways.

Step down transformer formula-

                  $V_s=\frac{N_s\times V_p}{N_p}$

We are given with the -

Primary voltage $V_p$ = 120V

Secondary voltage $Vs=12V$

Number of primary turns $N_p=125$

• To calculate the number of turns on the secondary coil -

       Since , the transformer ratio is given as -

                   $\frac{N_s}{N_p} =\frac{V_s}{V_p}$

So, the number of turns on the secondary coil is - $N_s=N_p\times\frac{V_p}{V_s}$

            Putting , the given values -:

                $125\times\frac{12}{120}$

         =   12.5

Therefore , the number of turns on secondary coil is 12.5 .