二、Revelation of the Working Principle

The operation of the transformer is based on the classic physical principle of electromagnetic induction. The formula is: , where  is the induced electromotive force,  is the power supply frequency,  is the number of winding turns, and  is the maximum magnetic flux.

When an alternating current flows merrily through the primary winding of the transformer, it creates a constantly changing alternating magnetic field around it. This magnetic field is like an enthusiastic messenger that passes through the elaborately designed iron core and then induces a voltage in the secondary winding. By ingeniously adjusting the turns ratio of the primary and secondary windings  (where  is the number of primary turns and  is the number of secondary turns), we can achieve various voltage transformations as we wish according to the formula , just like holding the magic wand of electricity.

三、Diverse Types to Meet Different Demands

1. High-Frequency Transformers

On the high-frequency stage of switching power supplies, high-frequency transformers are the well-deserved protagonists. With the characteristic of high-frequency operation, typically with a working frequency reaching tens of kHz or even hundreds of kHz, it successfully reduces the volume and weight of the transformer significantly. For instance, compared to traditional low-frequency transformers, the volume can be reduced by more than 50%, making significant contributions to the thinning and lightweight design of electronic devices and achieving high power density.

2. Planar Transformers

Planar transformers have emerged with their unique planar structure. This innovative design not only reduces the profile height, often only a fraction of the thickness of traditional transformers, but also brings excellent efficiency, which can reach over 95%, and superior thermal performance with a significantly reduced thermal resistance, becoming the favorite in high-density integrated circuit designs.