Template:ATX power connector
24-pin ATX12V 2.x power supply connector
(20-pin omits the last four: 11, 12, 23 and 24)
Color Signal Pin Pin Signal Color
Orange +3.3 V 1 13 +3.3 V Orange
+3.3 V sense Brown
Orange +3.3 V 2 14 −12 V Blue
Black Ground 3 15 Ground Black
Red +5 V 4 16 Power on Green
Black Ground 5 17 Ground Black
Red +5 V 6 18 Ground Black
Black Ground 7 19 Ground Black
Grey Power good 8 20 Reserved N/C
Purple +5 V standby 9 21 +5 V Red
Yellow +12 V 10 22 +5 V Red

Yellow +12 V 11 23 +5 V Red
Orange +3.3 V 12 24 Ground Black
  • Pins 8, 13, and 16 (shaded) are control signals, not power:
    • "Power On" is pulled up to +5V by the PSU, and must be driven low to turn on the PSU.
    • "Power good" is low when other outputs have not yet reached, or are about to leave, correct voltages.
    • The "+3.3 V sense" line is for remote sensing.[1]
  • Pin 20 (formerly −5V, white wire) is absent in current power supplies; it was optional in ATX and ATX12V ver. 1.2, and deleted as of ver. 1.3.
  • The right-hand pins are numbered 11–20 in the 20-pin version.
  1. ^ "ATX Specification Version 2.1" (PDF).


Template:AT power connector
AT power connector (Used on older AT style mainboards)
Color Pin Signal
P8.1 Power Good
P8.2 +5 V
P8.3 +12 V
P8.4 −12 V
P8.5 Ground
P8.6 Ground
P9.1 Ground
P9.2 Ground
P9.3 −5 V
P9.4 +5 V
P9.5 +5 V
P9.6 +5 V
Color Signal Pin Pin Signal Color
Orange +3.3 V 1
Orange +3.3 V 11
Orange +3.3 V 2
Black Ground 3 P8.5 Ground Black
Black Ground 13 P8.6 Ground Black
Black Ground 5 P9.1 Ground Black
Black Ground 15 P9.2 Ground Black
Black Ground 16
Black Ground 7
Black Ground 17
Red +5 V 4 P8.2 +5 V Red
Red +5 V 6 P9.4 +5 V Red
Red +5 V 19 P9.5 +5 V Red
Red +5 V 20 P9.6 +5 V Red
Yellow +12 V 10 P8.3 +12 V Yellow
Blue −12 V 12 P8.4 −12 V Blue
Green Power on 14 Ground Black
Grey Power Good 8 P8.1 Power Good Orange
N/C Reserved 18 P9.3 -5 V White
Purple +5 V standby 9