If someone suddenly mentions the power adapter to you, you may wonder what the power adapter is, but you may not expect that it is in the corner around you that you have almost forgotten. There are countless products matched with it, such as laptops, security cameras, repeaters, set-top boxes, it products, toys, audio, lighting, and other equipment, Its function is to convert the high voltage of 220 V at home into a stable low voltage of about 5V ~ 20V that these electronic products can operate. Today, I will introduce to my friends in detail what is a power adapter.
Generally, the power adapter is composed of shell, high-frequency transformer, wire, PCB circuit board, hardware, inductance, capacitor, control IC and other parts, as follows:
1. The function of varistor is that when the external current and voltage is too high, the resistance of varistor quickly becomes very small, and the fuse connected with varistor in series is blown, so as to protect other power circuits from being burned.
2. Fuse, with the specification of 2.5a/250v. When the current in the power circuit is too large, the fuse will blow to protect other components.
3. Inductance coil (also known as choke coil) is mainly used to reduce electromagnetic interference.
4. Rectifier bridge, d3sb in specification, is used to convert 220V AC into DC.
5. The filter capacitor is 180uf / 400V, which can filter the AC ripple in DC and make the operation of power circuit more reliable.
6. Operational amplifier IC (integrated circuit) is an important part of protection power supply circuit and current and voltage regulation.
7. The temperature probe is used to detect the internal temperature of the power adapter. When the temperature is higher than a certain set value (the set temperature threshold of different brands of power adapters is slightly different), the protection power circuit will cut off the current and voltage output of the adapter, so the adapter will not be damaged.
8. The high-power switch tube is one of the key components in the power adapter. The power adapter can operate “on and off”, and the power of the switch tube is indispensable.
9. Switching transformer is one of the key components in power adapter.
10. The secondary rectifier turns low-voltage AC into low-voltage DC. In IBM’s power adapter, the rectifier is usually operated by two high-power in parallel to obtain a relatively large current output.
11. There are two secondary filter capacitors with specifications of 820uf / 25V, which can filter the ripple in low-voltage DC. In addition to the above components, there are adjustable potentiometers and other resistance capacitance components on the circuit board.
Post time: Mar-29-2022
