Page 131 - Physics - XII

For an ideal transformer, there is no loss of energy. So, the output power should be equal to the input power.
∴ I E = I E
P P S S
I P = E S = K
I S E P
Procedure
1. Take a soft iron rod and cover it with a thick paper.
2. Wound a large number of turns of thin copper wire around the thick paper to prepare the primary coil
of the transformer.
3. With a sheet of paper, cover the primary coil and wound relatively smaller number of turns of thick
copper wire on it to prepare a secondary coil of step-down transformer.
4. Connect the ends of primary coil (P and P ) to a 220 V A.C. mains.
1
2
5. Note the least count and zero error (if any) of voltmeter and ammeter.
6. Measure the input voltage and current using A.C. voltmeter and A.C. ammeter, respectively.
7. Next, connect the ends of secondary coil (S and S ) to the A.C. voltmeter and A.C. ammeter and again
2
1
measure the output voltage and current.
8. Now, connect the ends S and S of secondary coil to A.C. mains (220 V) and measure voltage and
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2
current through primary coil and secondary coil of step-up transformer.
9. Repeat all the above steps for other self-made transformers by changing the number of turns of primary
and secondary coils.

Observations

Applied A.C. voltage = _____ V
LC (Least count) of A.C. voltmeter = _____ V

Zero error of voltmeter = _____ V
Range of voltmeter = 0 to _____ V
LC (Least Count) of A.C. ammeter = _____ A

Zero error of ammeter = _____ A
Range of ammeter = 0 to _____ A

Table for investigating the Relation between E and E and N and N
S P S P
S. Number of Number of Voltage in Voltage in Current in Current in Power
No. turns in the turns in the primary secondary primary secondary loss
primary secondary coil coil coil coil
coil coil (E ) (E ) (I ) (I )
(N ) (N ) P S P S
P S
1.
2.
3.

4.
5.

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