Diy power supply from an old computer psu

From wikiluntti

Introduction

Theory

12 V and 5 V.

Current

Wire Coloring

  • Black: Ground
  • Red: + 5V
  • Yellow: +12V
  • Orange: +3.3V
  • White: -5V
  • Blue: -12V
  • Purple: +5V standby
  • Grey: power on indicator
  • Green: ON/OFF switch

Power Switch

This system need to reverse the GND and 12V line.

  • Yellow cable (12V) on the colored terminal,
  • a black wire (GND) to the pin opposite,
  • the green cable (ON/OFF) to the centre pin.

In normal operation illuminated SPST switches have 3 terminals

  • the centre pin: green Power ON/OFF
  • one is indicated either by a different colour or labelled GND.
  • The terminal opposite would normally be wired with 12V,

The Fake Load

10W 10Ω resistor between 5V (red) and GND lines.

References