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Transformer and inductor

  1. May 18, 2015 #1
    what is the difference between inductor and a transformer...or a solenoid and a transformer
  2. jcsd
  3. May 18, 2015 #2


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    Gold Member

    This question could be answered with a million pages if you want to follow it down the rabbit hole..

    But basically here is what's up:

    An inductor is a two terminal device that stores energy in a magnetic field. (Pass a current through it, it sustains a magnetic field. If the current signal is time varying then so is the field).

    A solenoid (basically an electrically controlled switch) just uses an inductors magnetic field to close a switch. An example of a solenoid is in an electric starter for a vehicle with a large engine (marine application). You energize an inductor with a low voltage circuit, then the magnetic field closes a switch in a circuit which carries a much higher current to turn the motor.

    A transformer is just two inductors which are placed close to one another. Only one of the inductors receives a signal. If this signal is time-varying, then the other inductor will exist within a time varying magnetic field. Faradays law says that a voltage will be developed aross the secondary coil at a voltage which may differ from the voltage applied to the first inductor (depends on the number of windings / ratio).

    To summarize, inductor is a device that stores energy in a magnetic field. Alone it has many uses.
    Solenoid uses an inductor to close/open a switch when energized.
    Transformer uses two inductors to change voltage/current levels
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