A first look at high frequency transformers, an introduction to the transformer principle

1、Introduction to the principle of transformer

Transformer as the name implies, change the voltage of the electronic power apparatus. It is the use of Faraday electromagnetic induction principle to change the AC voltage device, mainly by the primary coil, iron core, secondary coil and other components. It can achieve input and output current, voltage and impedance matching conversion, etc. It can also achieve physical isolation of the primary stage. According to the different voltage of the initial stage, it can be divided into step-down transformer, step-up transformer, isolation transformer, etc.

2、 According to the different working frequency, divided into low frequency transformer and high frequency transformer.

The frequency of our daily life production electricity is 50 Hz, we call this AC power low frequency AC power. If the transformer works at this frequency, we make this transformer a low-frequency transformer, also called industrial frequency transformer. This type of transformer is large and inefficient, the core is made by stacking silicon steel sheets insulated from each other, the primary and secondary coils are wound with enamelled wire and the initial stage voltage is proportional to their number of turns.

In addition to this, some transformers operate at tens of settings of several hundred kilohertz, and such transformers become high frequency transformers. High frequency transformers generally do not use an iron core, but a magnetic core. High-frequency transformers are compact, with a small number of primary and secondary coil turns and high efficiency.

3、High and low frequency transformer difference and contact.

High frequency transformer operating frequency is generally in tens of kilohertz to hundreds of kilohertz, the transformer uses a magnetic core, the main component of the core is manganese zinc ferrite, this material in the high frequency eddy current is small, low loss, high efficiency. Low frequency transformer operating frequency domestic for 50 Hz, transformer core is a metal soft magnetic material, thin sheet of silicon steel can greatly reduce eddy current loss, but than the high frequency transformer core loss is still large.

The same output power transformer, high-frequency transformer than low-frequency transformer volume is much smaller, low heat generation. Therefore, many current consumer electronics and network products power adapter, are switching power supply, the internal high-frequency transformer is the most important component of the switching power supply. The basic principle is to first turn the input AC into DC and then through the transistor or field-effect tube into high-frequency through the high-frequency transformer voltage, after rectification again output, plus other control parts, stable output DC voltage.

In short, high and low frequency transformers are the same in the use of electromagnetic induction principle, the difference in the low frequency transformer is a silicon steel sheet stacked into the metal core, high frequency transformer is manganese zinc ferrite and other materials butt into the whole block.