Power supply unit (PSU) is a component that provides power to the entire computer. If the power supply unit is failure, the computer cannot work.
1. Function of power supply unit (PSU)
PSU used to convert AC current into DC voltage for supplying components on mainboard.
2. Types of power supply unit (PSU)
The power supply unit has many design standards such as AT, ATX, BTX corresponding to each type of motherboard.
AT power supply unit
Intel introduced in 1984, used in old computers with weak power. Can only be turned off by pressing the power switch.
ATX power supply unit
- Allows power off by software.
- Intel introduced in 1996. It has 20 pins.
- ATX12V has 20 pins + 4 pins.
In addition, there is BTX power supply unit, which is a type to replace ATX.
3. Structure of power supply unit
(1) Cooling fan
(2) Types of power connector
(3) Power on and power off switch
(4) AC power connector
Power supply unit specifications: see the back of the power supply unit
- Voltage
- Amperage
- Wattage
Commonly used power supply unit such as ACBEL 450W, Cooler Master 500W, Corsair 550W.
4. Types of connector of PSU
Connector of ATX12V power supply unit: ATX12V power supply unit has connectors such as main power, cpu power, molex power, SATA power, etc.
Main connector of ATX power supply unit
- Orange wire: 3.3V
- Red wire: 5V
- Yellow wire: 12V
- Blue wire: -12V
- White wire: -5V
- Purple wire: 5VSB
- Black wire: ground
- Green wire: open main power
- Gray wire: indicates good power on the ATX power supply unit
Connector of CPU power
- Supply power for CPU regulation circuit
- Black wire: ground
- Yellow wire: 12V
Connector of hard disk drive power
There are 2 types: connector ATA and SATA.
5. How to check the power supply unit ATX?
To check the power supply unit, we use a metal conductor to connect pin 14 (green) to pin 16 (or any black pin) on the main connector of power supply unit ATX. Then, supply AC power to the power supply unit. If the power supply unit’s cooling fan rotates, the power supply is still working and vice versa.
