The power supply is the heart of the host, providing continuous energy for the stable work of the computer. Located in different market segments of the power supply, the number of output wires may be different, but are inseparable from the colorful 9 colors: yellow, red, orange, purple, blue, white, gray, green, black (the current mainstream power supply has omitted the white line), then, what do these different colors represent? How do they correspond to the voltage?

Yellow: +12V
    The yellow line in the power supply should be a larger number of one, with the addition of CPU and PCI-E graphics card power supply components, +12V role in the power supply plays an important role.
    +12V provides power for the main shaft motor and seek motor of the hard disk, optical drive, floppy drive in the PC, and provides the operating voltage for the ISA slot and the circuit logic signal level as a serial device. When the +12V voltage output is abnormal, the reading performance of hard disks, CD-ROM drives, and floppy drives is often unstable. When the voltage is low, the performance is that the CD-ROM drive is seriously picked, the logical bad sectors of the hard disk are increased, and the bad sectors often appear, and the system is easy to crash and cannot be used normally. When it is high, the speed of the optical drive is too high, it is easy to get out of control, it is easy to fry the disk, and the hard disk is stalling and flying. At present, if the +12V power supply shortage will directly affect the performance of the PCI-E graphics card, and affect the CPU, directly causing a crash.

Red: +5V
    The number of +5V wires is equivalent to the yellow wires, and the +5V power supply is the working voltage provided to the CPU and integrated circuits such as PCI, AGP, ISA, and is the main working power supply in the computer. At present, the CPU uses a +12V and +5V hybrid power supply, and the requirements for it are not as high as before. Only in the latest Intel ATX 12V 2.2 version to strengthen the +5V power supply capability, strengthen the dual-core CPU power supply. The quality of its power supply is directly related to the stability of the computer system.

Orange: +3.3V
    This is specifically set up by the ATX power supply to provide power to the memory. In the latest 24pin main interface power supply, the +3.3V power supply is emphasized. The voltage requirements are strict, the output is stable, the ripple coefficient is small, and the output current is large, which is more than 20 amps. Some high-grade motherboards use high-power field tubes to control the power supply of the memory for safety, but it will also burn the tube because the memory is inserted. Platforms using +2.5V DDR memory and +1.8V DDR2 memory have voltage conversion circuits installed on the motherboard.

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

Blue: -12V
    The voltage of -12V provides the logical judgment level for the serial port, and the 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, which has a wide range.

White: -5V
    At present, there are few commercially available power supplies with white wires, white-5V is also for the logic circuit to provide a judgment level, the need for a small current, generally will not affect the normal operation of the system, basically optional.

Green: P-ON(power switch end)
    Power on is controlled by the level. When the signal level of the 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 the pin, which is generally about 4V. Because the voltage output of the pin is the signal level. Here is a preliminary method to determine whether the power supply is good or bad: Use a metal wire to short connect the green port and any black port. If the power supply does not respond, it indicates that the power supply is damaged. Many of the current power supply has added a protection circuit, and it is judged that there is no additional load after short-circuited power supply, and it will automatically shut down. Therefore, you need to carefully observe the power of the moment to start.

Gray: P-OK(Power signal cable)
    Under normal circumstances, if the output of the gray line P-OK is above 2V, then this power supply can be used normally; If the output of P-OK is below 1V, this power supply will not guarantee the normal operation of the system and must be replaced. This is also one of the main means of judging the life of the power supply and whether it is qualified.
    Recognizing the corresponding relationship between the power output wire and the voltage can help us understand the output specifications of the power supply more clearly, which is very useful in the purchase of power supplies and troubleshooting power supplies.