Benchtop Power Supply from ATX PSU

Pulled a Power Supply Unit (PSU) from an old PC. Tapped off the +5V, +3.3V, and +12V lines and connected them to screw-posts, plus another +12V tap going through a regulator to give me a variable 0-to-about-10V port. The potentiometer shaft controls the variable voltage tap. LEDs for power-on (red) and standby (green), plus a front-panel power switch round out the device. Oh, and a handle scavenged from the miscellaneous part box. :)


  • figure out the amp rating of the variable tap
  • put fuses (probaby ~0.5A) on all taps
  • printed labels for the front panel (include gradations for the potentiometer with useful voltages labeled, e.g., 9v, 7.4v)
  • storage for test leads and the wall plug cable
  • trim the potentiometer shaft and attach a knob

Front and back pics. Yes, I still have a lot to learn about tidy cabling.

A pic of it hooked up to a "mystery motor" I scavenged from an old printer, to see how much voltage the motor can take (answer: probably a lot more than the PSU can put out -- I'm guessing it's a 24V motor, from the way it purrs at 12V).