we recondition an ATX power supply to power our electronics
Salvaging parts from computers can be very useful especially the ATX power supply as it can be converted to a lab bench power supply giving us +3.3V +5V +12V -12V -5V outputs with lots of power ,mine a 300W unit gives up to 30A on the 5V output which can be very useful.
Let’s gather the parts and start making our power supply , forget about batteries and cell phone chargers to power our circuits :
About The Circuit
What we need?
- 5x Binding posts (red)
- 1x Binding post (black)
- 1x Toggle Switch
- 1x 3mm Green LED
- 1x 3mm Red LED
- 2x 220Ω Resistor for the led’s
- Dummy Load
Hers an image explaining the color code of the wires of a power supply :
the dummy load on the supply output is required to keep it stable even when we only draw small amounts of current. Old power supply’s use the most amount of power on the 5v rail, so i connected the dummy load on the 5v if you have a newer power supply you’ll need to put them on the 12v rail.
Assuming the dummy load should draw at least 0.5A.
- Here is the calculation if you have most of your power on 5V/3,3V rail:
2. Here is the calculation if you have most of your power on 12V rail:
If you have most of your power on the 12V rail then you need to connect a 24Ω resistor to 12V instead of 10Ω to 5V.
- 5v => 10Ω draws 2.5W
- 12V => 24 draws 6W