P8 AT power supply connector

Pin Name Color Description
1 PG Orange Power Good, +5 VDC when all voltages has stabilized.
2 +5V Red +5 VDC (or n/c)
3 +12V Yellow +12 VDC
4 -12V Blue -12 VDC
5 GND Black Ground
6 GND Black Ground
P9 AT power supply connector
Pin Name Color Description
1 GND Black Ground
2 GND Black Ground
3 -5V White or Yellow -5 VDC
4 +5V Red +5 VDC
5 +5V Red +5 VDC
6 +5V Red +5 VDC


ATX P/S PINOUT VOLTAGE
ATX specification includes not only Power Supply Unit, but also case and motherboard. In addition to old AT standard, one extra voltage line is available(+3.3V), connector changed to a single 20-pin and power supply uses a power-on wire, allowing PSU to be turned off by software.


Pin Name Color Description
1 3.3V Orange +3.3 VDC
2 3.3V Orange +3.3 VDC
3 COM Black Ground
4 5V Red +5 VDC
5 COM Black Ground
6 5V Red +5 VDC
7 COM Black Ground
8 PWR_OK Gray Power Ok (is a status signal generated by the power supply to notify the computer that the DC operating voltages are within the ranges required for proper computer operation)
9 5VSB Purple +5 VDC Standby Voltage (max 10mA)
10 12V Yellow +12 VDC
11 3.3V Orange +3.3 VDC
12 -12V Blue -12 VDC
13 COM Black Ground
14 /PS_ON Green Power Supply On (active low). Short this pin to GND to switch power supply ON, disconnect from GND to switch OFF.
15 COM Black Ground
16 COM Black Ground
17 COM Black Ground
18 -5V White -5 VDC
19 5V Red +5 VDC
20 5V Red +5 VDC
/PSON activated by pressing and releasing the power button while the power supply is in standby mode. Activating /PSON connects the power supply’s /PSON input to ground, thereby switching the power supply to full-on condition.


THE NEW ATX P/S
Changes to ATX standard were made to support 75 watt PCI Express requirements. New ATX v 2.x uses new connector, but most motherboards nowdays allow to use an old ATX v 1.x power supply with 20 pin connector - it connects to 24 pin motherboard receptacle.



Pin Name Color Description
1 3.3V Orange +3.3 VDC
2 3.3V Orange +3.3 VDC
3 COM Black Ground
4 5V Red +5 VDC
5 COM Black Ground
6 5V Red +5 VDC
7 COM Black Ground
8 PWR_OK Gray Power Ok is a status signal generated by the power supply to notify the computer that the DC operating voltages are within the ranges required for proper computer operation
9 5VSB Purple +5 VDC Standby Voltage (max 10mA)
10 12V Yellow +12 VDC
11 12V Yellow +12 VDC
12 3.3V Orange +3.3 VDC
13 3.3V Orange +3.3 VDC
14 -12V Blue -12 VDC
15 COM Black Ground
16 /PS_ON Green Power Supply On (active low). Short this pin to GND to switch power supply ON, disconnect from GND to switch OFF.
17 COM Black Ground
18 COM Black Ground
19 COM Black Ground
20 -5V White -5 VDC
21 +5V Red +5 VDC
22 +5V Red +5 VDC
23 +5V Red +5 VDC
24 COM Black Ground
/PSON activated by pressing and releasing the power button while the power supply is in standby mode. Activating /PSON connects the power supply’s /PSON input to ground, thereby switching the power supply to full-on condition.