what does 'transformer' in electrical term mean?

Answer 1

A transformer is a device that takes an input voltage, and outputs a different voltage (transforming that voltage). It does this using two coiled bundles of wire whose magnetic fields affect each other.

For example, you might have a 10,000-volt potential on a long-distance transmission line. A transformer might scale down the voltage to 220 volts for use in a household setting.

You can learn more here:
http://en.wikipedia.org/wiki/Transformer

Answer 2

In addition to the package of coils with their magnetic fields linked being used to transform from one voltage to another (in the ratio of output coil turns to input coil turns) it can also be used to transform current for measurements. That is beyond what was described in the correct answers above.

Most instrumentation that wants to know how much current is flowing in a large circuit will have an input coil in series with the big load and will have an output coil connected to a meter. The meter will not have to handle a load that could be hundreds or thousands of amps because it is in the secondary and its current is reduced by the transformer ratio.

Answer 3

When an alternating current i.e AC voltage is applied to 1st coil of wire tightly wound with a 2nd coil of wire the coupled magnetic fields induces a voltage in the 2nd coil. The induced 2nd coil AC voltage can be less than, equal or greater than the 1st coil AC voltage depending on the turns ratio of the 2nd coil to the 1st coil.
V2 = V1 * ( N2 / N1 )
Thus the 1st coil voltage is transformed to the 2nd coil voltage.

Answer 4

A transformer changes the voltage from one voltage to another voltage either greater or less

Answer 5

it transforms the voltage to a higher or lower voltage.

either by stepping it up or stepping it down. thus
the term transformer.

example incoming voltage 100Volts outgoing voltage is
200 volts. a boost transformer.