Difference between revisions of "power supply units"

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<span style="background:#00ff00">&nbsp;&nbsp;&nbsp;&nbsp;</span>&nbsp;GREEN:  Power on. Ground this line to turn '''ON'''.
 
<span style="background:#00ff00">&nbsp;&nbsp;&nbsp;&nbsp;</span>&nbsp;GREEN:  Power on. Ground this line to turn '''ON'''.
  
<span style="background:#ffff00">&nbsp;&nbsp;&nbsp;&nbsp;</span>&nbsp;YELLOW: +12V
+
<span style="background:#ffff00">&nbsp;&nbsp;&nbsp;&nbsp;</span>&nbsp;YELLOW: +12V. On newer power supplies you may need to attach a 22&#8486; 10 Watt resistor to GND as a dummy load. Switching power supplies usually need at least some load to operate properly.
  
 
<span style="background:#0000ff">&nbsp;&nbsp;&nbsp;&nbsp;</span>&nbsp;BLUE:  -12V
 
<span style="background:#0000ff">&nbsp;&nbsp;&nbsp;&nbsp;</span>&nbsp;BLUE:  -12V
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<span style="background:#ff8800">&nbsp;&nbsp;&nbsp;&nbsp;</span>&nbsp;ORANGE: +3.3V
 
<span style="background:#ff8800">&nbsp;&nbsp;&nbsp;&nbsp;</span>&nbsp;ORANGE: +3.3V
  
<span style="background:#ff0000">&nbsp;&nbsp;&nbsp;&nbsp;</span>&nbsp;RED:    +5V. Attach a 5&#8486; resistor to GND as a dummy load. Switching power supplies usually need at least some load to operate properly.  
+
<span style="background:#ff0000">&nbsp;&nbsp;&nbsp;&nbsp;</span>&nbsp;RED:    +5V. On older power supplies you may need to attach a 5&#8486; 10 Watt resistor to GND as a dummy load. Switching power supplies usually need at least some load to operate properly.  
  
 
<span style="background:#8800ff">&nbsp;&nbsp;&nbsp;&nbsp;</span>&nbsp;PURPLE: +5V standby. This provides low power 5V even when "off".
 
<span style="background:#8800ff">&nbsp;&nbsp;&nbsp;&nbsp;</span>&nbsp;PURPLE: +5V standby. This provides low power 5V even when "off".

Revision as of 11:45, 16 December 2011


Obtain an ATX PSU.


     BLACK: GND ground

     GREEN: Power on. Ground this line to turn ON.

     YELLOW: +12V. On newer power supplies you may need to attach a 22Ω 10 Watt resistor to GND as a dummy load. Switching power supplies usually need at least some load to operate properly.

     BLUE: -12V

     ORANGE: +3.3V

     RED: +5V. On older power supplies you may need to attach a 5Ω 10 Watt resistor to GND as a dummy load. Switching power supplies usually need at least some load to operate properly.

     PURPLE: +5V standby. This provides low power 5V even when "off".

     WHITE: -5V (rare)

     GRAY: Power OK signal line. Attach an LED in series with 330Ω resistor for a power ready light.

     BROWN: +3.3V remote sense. This may not be necessary for all applications. You should attach this to the +3.3V      ORANGE line. The attachment point should be near the load, not just inside the PSU. This allows the PSU to measure the resistance of the power lines leading to the load and fine tune the voltage level. For long power lines the voltage drop can be significant.