# Transformers - explanation

Explain what a transformer is, why it is not 100% efficient and state its uses in real life.

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TRANSFORMERS

Transformers can increase the voltage and reduce the current of an oscillating signal or vice versa, by having two coils of wire wrapped around a single core.

The general principle involves Faraday's Law which states that the rate of change of flux linked to a coil is equal to the emf induced. Hence if we have an oscillating voltage in a primary coil we generate lines of flux which can then be linked into a secondary coil, producing a voltage. The amount of flux linkage is determined by the number of turns on each coil, the size of the magnetic field and the area of the coil. Here we are only varying the number of turns on each coil, N1 and N2, and therefore the ratio of the voltages is given by V2/V1 = N1/N2.

This is strictly only true for an ideal transformer, where ...

#### Solution Summary

Transformers can increase the voltage and reduce the current of an oscillating signal or vice versa, by having two coils of wire wrapped around a single core.