​The ring indicates the number of primary and secondary windings of the voltage transformer. One primary winding is removed, and the rest are all secondary windings.

The design of switching power transformer is divided into three aspects: reduce the loss of switching transformer as far as possible; Minimize leakage of switching transformer; Try to suppress the audio noise of the switching transformer.

The audio transformer can realize voltage-converter conversion just like the power transformer, and can also realize audio signal coupling. There are four main functions of audio transformer:Output transformer: used in audio equipment and playback equipment, impedance conversion in the circuit.

Isolation transformer belongs to the safety power supply, generally used for machine repair, maintenance, protection, lightning protection, filtering function. The principle of isolation transformer is the same as that of ordinary transformer. They all use the principle of electromagnetic induction. Isolation transformers generally (but not all) refer to 1:1 transformers.

the structure of the power transformer:(1) Rectifier；(2) Filter；(3) Inverter；(4) Power factor correction: