Generally speaking, the functions of the power adapter are transformers and rectifiers. The AC power at home is 220V, and the computer is 12V DC, so we can be sure that the power adapter is a transformer and a rectifier. The adapter is a transformer,

So we should know that AC 220V is converted into voltage through transformer, DC is converted into voltage through rectifier, there is consumption, and these consumption will be converted into heat, so it is normal for the power adapter to heat up.

The transformer is made of silicon steel sheets. When the transformer is energized, a magnetic flux is generated. It is normal for the magnetic flux to exert a force between the silicon steel sheets, creating a humming sound. But too loud is not normal for a number of reasons:1. The AC voltage is unstable.

2. The chip is damaged.

3. Inter-turn short circuit.

4. Component damage, etc. By the way, the purpose of the adapter is to convert alternating current into direct current

In order to save the design volume and space of the product, it is easy to replace, and the adapter is practical to use, generally speaking, the higher the voltage, the more dangerous it is to put inside the machine.

Therefore, the separation of the power adapter and the device is mainly to isolate the area of high and low voltage conversion, and the equipment is relatively safer. The cost is also lower.