Investigating the Number of Turns in a coil which affects the voltage

Fair Test

I will keep the input supply and the number of turns on the supply the same

I will alter the number of turns of wire on the secondary coil

I will measure the output voltage from the second coil.

Prediction

Faraday's law states that: "The induced e.m.f in a wire is dependent upon the rate of the 'change of flux' The magnetic field around the primary will remain constant and alternating at the same speed throughout the experiment, as the number of coils and the input supply will remain constant, therefore the more coils of wire that are cut by the alternating current, the greater the secondary voltage that will be induced. This is because the lines of flux cut more wire.

Background Knowledge

I know that an alternating current is required to induce a current using a primary coil in a secondary coil. This is because the alternating current creates a constantly alternating magnetic field around the laminated soft iron core. This change in the magnetic field is responsible for the induced current in the secondary. I also know that the laminated soft iron core whilst not being vital for the operation of the transformer, increases efficiency by reducing eddy currents and linking the coils more effectively.

Results

Number of turns

st Voltage reading (V) (+-0.005)

2nd Voltage reading (V)(+-0.005)

0.17

0.17

5

0.50

0.50

0

0.92

0.93

20

.85

.87

30

2.88

2.89

40

3.77

3.88

50

4.76

4.76

Conclusion

The as the number of turns increases on the secondary, according to my graph, the voltage increases in direct proportion to it. I can therefore assume that the greater the number of turns on the secondary coil, provided the power supply and the number of turns on the primary remain constant, the greater the voltage output. This is because for each extra turn of wire, as I predicted, the same number of lines of flux cut it, therefore the more wires that are cut by the changing magnetic field, the greater the current as effectively more lines of flux are cut per unit time.

Evaluation

I think that on the whole my results are accurate. However, to improve my experiment further, I would take the results 5 times in order to prove that the values are completely accurate. I could also investigate a higher number of coils on the secondary and discover if in fact the voltage increases exponentially to infinity. This would improve my experiment considerably. I would also like to investigate the change in current during this experiment using digital Ammeters as well as digital Voltmeters so that I can investigate the change in current as the voltage increases. I assume that the current would decrease as the voltage increases, therefore balancing the result.