Mod your ATX power supply into an adjustable lab power supply!

Modifying the feedback path of an ATX power supply allows you to adjust the voltage of the outputs. The result is a very cheap, efficient, stable supply which can output from 3.1V to around 28V, at up to 3 amps, perhaps more. WARNING: I am not responsible if you electrocute yourself. A computer power supply / ATX power supply is mains operated equipment. It can have voltages of up to 350V across some components when live. Be very careful when working with one. Take all precautions, a shock could be fatal, at the very least it can cause burns and hurts a lot! I used a 1k pot and an old 120W ELENCO power supply. It may well work with different power supplies. In my case, I found I was able to get the rails to vary quite significantly. Your mileage vary vary. 12V: 10.6V – 28.5V 5V: 4.8V – 11.5V 3.3V: 3.1V – 8.5V -12V: -11.1V to -30V 5Vsb: constant 5.06V Future ideas are to add a linear pass transistor voltage regulator on the output – this would drop a few volts but significantly reduce ripple, and to add a microcontroller for features like constant current/constant power/current limited and automatic switching between rails to achieve a full 0-25V range.

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