## Why high frequency transformers are small？

Since traditional transformers can’t meet today’s efficiency requirements, high-frequency transformers were invented. High-frequency transformers improve efficiency, as well as save power, and have a longer service life than standard transformers.

Furthermore, it has the double benefit of reducing energy consumption while also protecting the environment. One of the reasons why high-frequency transformers are so popular is their small size. How can smaller transformers be more effective than larger ones?

### In transformer design, the higher the frequency, the smaller the core and the fewer turns per volt are required for the same power.

Magnetic core is the first consideration in the design of high frequency transformers. In a high frequency transformer, soft magnetic material is used as the core. It is efficient, has low coercivity, and possesses high electrical conductivity. With a large number of turns of the coil, the electromagnetic field can withstand a high voltage through a small excitation current. Therefore, the core volume of the transformer can be minimized under a certain power requirement. The transformer also has a small volume.

### 2. Based on Maxwell’s equation, the induced electromotive force E in the transformer coil is:

In a transformer coil, the induced electromotive force E is equal to the integral of the rate of change of the magnetic flux density B over time in N turns of area Ac. In the transformer, the induced electromotive force E on the primary side and the voltage U applied on the input side are essentially equal. That is to say, under the assumption that U amplitude remains at the same level, E amplitude remains unchanged. Moreover, the magnetic flux density B of each magnetic core type has an upper limit. The ferrite used in high frequency transformers is only a few tenths of a Tesla, and the iron cores used in industrial transformers are about slightly larger than one. Therefore, when the frequency is increased and the peak magnetic flux density B does not systematically change, the rate of change of the magnetic flux density in each cycle, dB/dt, is greatly increased. Thus, a smaller Ac or N can be used to produce the same induced electromotive force E. Whether Ac or N should be reduced can help achieve a smaller magnetic core volume, thereby resulting in a smaller high-frequency transformer. Both can help achieve a smaller magnetic core volume, thereby resulting in a smaller high-frequency transformer size.

## High frequency transformers size is determined by what factors?

- A cross-sectional area at the core
- Number of turns in a winding
- The diameter of the copper wires that make up a winding
- The cooling method
- Power output