Function of transformer

Transformer (transformer) is an electromagnetic device whose functions can be roughly divided into the following functions:

1. You can increase or decrease the value of AC voltage or current at will

2. Used as impedance matching equipment: Transformers can be used to match unbalanced impedance. For example, the output impedance of a certain amplifier is 20 ohms, and it is connected to a 4 ohm speaker. At this time, a transformer must be used to match the two impedances with the correct turns ratio.

3. Used for signal transmission. Some signals require electrical isolation. At this time, a transformer is useful.

4. Use and oscillation circuit as feedback element

The transformer uses the mutual inductance principle of the coil to change the voltage. In fact, the change in the magnetic field of one inductor can cause another inductor to generate an induced voltage at a close distance. This effect is called mutual inductance (Mutual Inductance).

When an alternating voltage (V1) is supplied to the coil of the primary winding, since the intensity and polarity of the alternating current are constantly changing positive and negative, the number of magnetic lines of force generated by the coil of the primary winding keeps changing. Due to the continuous change of the magnetic field strength, the other end coil wound on the same iron core is prompted to generate an induced electromotive force V2. The transformer cannot convert the DC voltage. This is because the magnetic field must change to make the secondary winding produce an induced voltage; the magnetic flux passing through the primary and secondary windings at any instant is the same, so the induced electromotive force in each turn of the coil is the same. (dc) The magnetic field will not change, so there will be no induced voltage. If the DC voltage is imposed on the transformer, the transformer may be burnt.