Difference between revisions of "power supply units"
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<span style="background:#ff8800"> </span> ORANGE: +3.3V | <span style="background:#ff8800"> </span> ORANGE: +3.3V | ||
| − | <span style="background:#ff0000"> </span> RED: +5V | + | <span style="background:#ff0000"> </span> RED: +5V. Attach a 5Ω resistor to GND as a dummy load. Switching power supplies usually need at least some load to operate properly. |
<span style="background:#8800ff"> </span> PURPLE: +5V standby. This provides low power 5V even when "off". | <span style="background:#8800ff"> </span> PURPLE: +5V standby. This provides low power 5V even when "off". | ||
| Line 20: | Line 20: | ||
<span style="background:#ffffff"> </span> WHITE: -5V (rare) | <span style="background:#ffffff"> </span> WHITE: -5V (rare) | ||
| − | <span style="background:#444444"> </span> GRAY: Power OK signal line | + | <span style="background:#444444"> </span> GRAY: Power OK signal line. Attach an LED in series with 330Ω resistor for a power ready light. |
| − | <span style="background:#884400"> </span> BROWN: +3.3V remote sense | + | <span style="background:#884400"> </span> BROWN: +3.3V remote sense. This may not be necessary for all applications. You should attach this to the +3.3V <span style="background:#ff8800"> </span> 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. |
Revision as of 11:40, 16 December 2011
Obtain an ATX PSU.
BLACK: GND ground
GREEN: Power on. Ground this line to turn ON.
YELLOW: +12V
BLUE: -12V
ORANGE: +3.3V
RED: +5V. Attach a 5Ω 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.
