PC Power Supply

If you are ever looking for a good power source for 12 V or 5 V devices, look no further than an old PC power supply.  A few simple modifications are all it takes to get one of these to provide clean 12 V and 5 V power.  Most modern PC power supplies do not have real "on-off" switches and require the motherboard to tell the power supply to turn on.  You can simulate this by connecting the on-off wire (usually green)  to the common (usually black).  If your power supply is a standard ATX supply, refer to the pinout to verify the location of these pins.  You can then use the 5 V (usually red) and 12 V (usually yellow) power pins to your device.  These supplies can also supply -12 V & 3.3 V (usually orange).  These are also useful for some electronic devices.  If you do attempt to convert your old computer power supply be very careful as there are hazardous voltages inside.