Simple ATX bench power supply


For some time I had this old ATX power supply gathering dust and getting moved from one place to another. I kept wanting to transform it into a bench supply. ATX supplies are switched power supplies that can provide a lot of current. They have a set fixed of voltages (5V, 3.3V, 12V, -12V), nonetheless very useful for most electronics and low voltage high-power projects. Once nice thing is that you can combine outputs to get less conventional voltages, for instance you can use 3.3V as GND and 5V as VDD to get an effective 1.7V potential difference which could come in handy in some projects; you could also use -12v as GND and 12V as VDD to get a 24V range for your project. Be warned if  you try that though – if your project has other GND sources that are connected to mains ground/earth you could potentially cause some sparks/smoke/flame/fireworks, since all the grounds in this supply are directly connected to mains earth – as revealed by a simple connectivity test between the supply input and output ground terminals.

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