red
Represents +5V motherboard circuit, memory module power supply, optical drive, hard disk and other equipment signal power supply

Note: The number of +5V wires is equivalent to the number of yellow wires. The +5V power supply is the working voltage provided to the CPU and integrated circuits such as PCI, AGP, ISA, etc. It is the main working power supply in the computer. CPUs all use a mixed power supply of +12V and +5V, and the requirements for it are not as high as before. Only the latest Intel ATX 12V 2.2 version has enhanced the +5V power supply capability to enhance the power supply for dual-core CPUs. The quality of its power supply is directly related to the system stability of the computer.

yellow
Represents +12V CPU and graphics card power supply; supplies power to standard drive circuits, such as optical drives and hard disk motors

Note: The yellow line should be one of the more numerous in the power supply. With the addition of CPU and PCI-E graphics card power supply components, the role of +12V plays an important role in the power supply.

orange color
Represents +3.3V, which is mostly used to power SATA hard drives and will be used for other purposes in the future.

Note: This is a specially designed ATX power supply to provide power for the memory. The latest 24pin main interface power supply focuses on strengthening the +3.3V power supply. The voltage requirements are strict, the output should be stable, the ripple coefficient should be small, and the output current should be large, above 20 amps. Some mid-to-high-end motherboards use high-power field tubes to control the power supply of the memory for safety reasons. However, the tubes may be burned when the memory is plugged in. Platforms using +2.5V DDR memory and +1.8V DDR2 memory have voltage conversion circuits installed on the motherboard.

Purple
Represents +5V (USB) USB device power supply, supports the boot function of USB keyboard and mouse (still powered after shutdown)

Description: The ATX power supply provides +5V 720MA power to the motherboard through PIN9. This power supply provides power for WOL (Wake-up On Lan), boot circuit, USB interface and other circuits. If you do not use functions such as network wake-up, please turn off such functions and remove the jumper to prevent these devices from drawing current from the +5VSB power supply terminal. The power supply quality of this output directly affects the power consumption of the computer during standby and is directly linked to our electricity bill.

black
Represents the ground wire (0V), a necessary component of the power supply circuit

Description: The ground wire of the system circuit.

green
Represents the PS-ON power-on signal line (when short-circuited with the ground wire, the power will be turned on)

Description: Control the power on through level. When the signal level of this port is greater than 1.8V, the main power supply is off; if the signal level is lower than 1.8V, the main power supply is on. Use a multimeter to test the output signal level of this pin, which is generally around 4V. Because the voltage output by this pin is the signal level. Here is a preliminary way to judge the quality of the power supply: use a metal wire to short-circuit the green port and any black port. If the power supply does not respond, it means that the power supply is damaged. Many power supplies have protection circuits added to them. After short-circuiting the power supply, it will automatically shut down when it is judged that there is no additional load. Therefore, everyone needs to carefully observe the moment when the power supply is turned on.

grey
Represents the Power Good monitoring line, which connects the motherboard and power supply and serves as signal feedback.

Note: Under normal circumstances, if the output of the gray line P-OK is above 2V, then the power supply can be used normally; if the output of P-OK is below 1V, the power supply will not guarantee the normal operation of the system and must be replaced. . This is also one of the main means to judge the life of the power supply and whether it is qualified. Recognizing the corresponding relationship between the power supply output wires and voltage can help us understand the output specifications of the power supply more clearly, which is very useful when purchasing a power supply and troubleshooting power supply faults.

blue
Represents -12V old serial port (rarely used)

Note: The voltage of -12V provides the logic judgment level for the serial port. The required current is not large, generally below 1A. Even if the voltage deviation is too large, it will not cause a fault because the 0 level of the logic level ranges from -3V to -15V. , has a wide range.

White
Represents -5V ISA bus (rarely used)

Note: There are few commercially available power supplies with white wires. The white -5V also provides a judgment level for logic circuits. It requires a very small current and generally does not affect the normal operation of the system. It is basically dispensable.