More and more users choose laptops because of their portability. Everyone knows that laptops have two power modes, one is battery-powered, the other is power adapter, and the power adapter is preferred. Although it is often used, it is not necessarily known.
What is the power adapter?
Power adapter, also known as external power supply, is a power supply conversion device for small portable electronic devices and electronic appliances. It is generally composed of a casing, a power transformer and a rectifier circuit. According to the connection method, it can be divided into wall-mounted and desktop. Common in small electronic products such as mobile phones, LCD monitors and notebook computers.
Its working principle is simple: it means that the unstable power supply uses the principle of switching power supply to convert the conversion circuit into the constant voltage DC power required by the notebook computer to supply and charge the notebook computer.
Power adapter construction
1. The varistor has the function that when the external voltage is too high, the resistance of the varistor quickly becomes very small, and the fuse connected in series with the varistor is blown, thereby protecting other circuits from being burned out.
2. The fuse. When the current in the circuit is too large, the fuse will blow to protect other components.
3, the inductor coil (choke), the main function is to reduce electromagnetic interference.
4, rectifier bridge, the role is to turn 220V AC into DC.
5, the filter capacitor, the function is to filter the AC ripple in the DC power, making the circuit work more reliable.
6, op amp IC (integrated circuit), protection circuit, an important part of 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 power adapter of different brands has a slightly different temperature threshold), the protection circuit will cut off the voltage of the adapter. Output to protect the adapter from damage.
8. The high-power switch tube is one of the core components in the switching power supply. The switching power supply can work “open and close”, and the switch tube is indispensable.
9. Switching transformer, one of the core components in the switching power supply.
10. Secondary rectifier, the function is to change the low-voltage alternating current into low-voltage direct current. In IBM’s power adapters, the rectifiers are often operated in parallel by two high powers to achieve a large current output.
11, the secondary filter capacitor, there are two, to filter out the ripple in the low-voltage DC.