8 steps for the operation of a regulated power supply
The working principle of the power supply is to convert the 220V AC power into the pure low-voltage DC power required by the computer. This process is very complicated. We use easy-to-understand pictures and texts to explain the working principle.
1. Press the switch key to introduce 220V AC.
2. Behind the switch key, there is a varistor. Its principle is exactly the same as that of the fuse used in our home. Whenever the short-circuit current at the output terminal is too large, it will cut off the current by self-fusing. to avoid damage to other equipment.
3. The current will pass through a set of coils and rectifier diodes, which will rectify the alternating current into pulsed direct current.
4. Then, the current converted into pulsed direct current will reach the capacitor part of the power supply. Generally, the power supply has two large capacitors, and one or two capacitors are selected by automatic switching as the voltage conversion between 110V/220V international (the voltage in our country is 220V, so two capacitors are generally selected), and the current becomes purer pulsed direct current after being filtered by the capacitor. Note: Capacitors used in general power supplies can be divided into explosion-proof capacitors and non-explosion-proof capacitors. These two types of capacitors are very easy to distinguish. There is a cross or Y-shaped groove on the top of the explosion-proof capacitor. Non-explosion-proof capacitors do not.
5. Then the current passes through the switching transistor. The switching transistor is the central hub of the switching power supply. It is mainly responsible for sending the pulsed direct current to the primary stage of the high-frequency transformer in batches according to a certain high-frequency frequency. What needs to be paid attention to is that the switching transistor is an easily damaged part, and it is the core of the switching power supply. Therefore, the quality of the switching transistor is closely related to the quality of the power supply.
6. Before entering the high-frequency transformer, the current will pass through MOSFETs (field effect transistors). Usually, the power supply will have a pair of MOSFETs, which can increase the power through complementarity. A good power supply will generally have more than four.
7. The high-frequency direct current with increased power enters the primary and inverter circuits of the high-frequency transformer, and then the stepped-down high-frequency and low-voltage alternating current is obtained.
8. Finally, the low-voltage alternating current passes through the rectifier diode again to convert the current into direct current with low voltage and strong current.
