# A transformer only works with which type of current

FAQ | Feb 09,2023

A transformer only works with which alternate current.Transformer is the use of alternating current mutual inductance phenomenon to change voltage, mutual inductance phenomenon only exists in AC circuit, DC no mutual inductance phenomenon.

We can also conclude from the working principle of the transformer that it is only suitable for alternating current. Transformer is the use of the principle of electromagnetic induction to change the AC voltage device, the main components are primary coil, secondary coil and core (magnetic core). In electrical equipment and wireless circuit, commonly used for lifting voltage, matching impedance, safety isolation, etc. In a generator, whether the coil moves through a magnetic field or the magnetic field moves through a stationary coil, an electric potential is induced in the coil. In these two cases, the value of the magnetic flux is unchanged, but the number of the magnetic flux of the chain intersecting the coil is changed, which is the principle of mutual induction. Transformer is a device that uses electromagnetic mutual inductance to transform voltage, current and impedance.

There is an alternating magnetic flux through a coil, the coil will produce induced electromotive force, in a transformer, AC current through the primary coil in the iron core to produce alternating magnetic flux, this alternating magnetic flux through the core through the secondary coil, so secondary induced electromotive force, secondary voltage. There is a condition that the flux must be alternating, that is, the primary voltage current must be alternating (induced electromotive force V=Ldi/dt, DC di/dt=0, so no EMF can be induced).

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