The function of power adapter is transformer and rectifier. Household AC is 220V, and our computer land is 12V DC (as if), so we can be sure that the power adapter is a transformer and rectifier. Then the adapter is a transformer. We should all know that AC 220V is transformed into voltage through the transformer and DC through the rectifier. There is consumption here, and these consumption will be transformed into heat, so it is normal for the power adapter to heat.
The transformer is made of silicon steel sheet. After the transformer is powered on, magnetic flux will be generated. The magnetic flux will cause the force between silicon steel sheets to produce buzzing sound, which is normal. But the earth sound is abnormal for many reasons: 1. The AC voltage is unstable. 2. The chip is broken. 3. Turn to turn short circuit. 4. The element is damaged.
It is widely used in consumer electronic products. Most of the output power provided is less than 100 watts, and the market demand is growing rapidly. Such as electric bicycle battery charger, small-size LCD TV, notebook computer, printer, DVD player and set-top box. Most of the early power adapters used linear transformers. With the requirements of consumer electronic products for high efficiency and wide input voltage range, and the increase of copper, iron and labor costs, most of the original linear transformers in this kind of power adapter were gradually replaced by switching power supply.
