Is there a simple way to make a computer power supply variable and maintain high current? I keep seeing designs that use LM317T's, but they're limited to 1.5 A or less. I'd like to be able to retain as much of the current as possible but keep it simple. Thoughts?
Thanks in advance, Jake
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By design, a computer power supply delivers high current at low voltages (5V and 3.3V), which are unlikely to be useful for anything BUT a computer. If you want a general-purpose power supply for experimentation, a 40V range and settable current limit are important qualities that the 'computer power supply' lacks.
A 'simple' power supply is a string of batteries. A flexible one, with knobs and meters, is easily built or purchased, but not simple.
Jake, PC power supplies are switchmode designs, designed for fixed output voltages needed by computer components. This means that the PSUs are designed to operate within very tight tolerances, limiting the adjustability to quite a small range. You would have to change the basic design of the SMPS control circuitry so that it could provide power over a wider range of voltages. Changing basic design of the supply also means changing or modifying a few major components in the PSU. Take a look at the page at
Bear in mind that these mods are still fixed voltage output, not variable. My suggestion, if you really need a high current variable bench supply, is to figure out what you actually need, in terms of voltage ancd current, and buy or build from scratch, a PSU that will fill your needs. Linear supplies are much easier to build than SMPS power supplies, especially variable voltage/high current units. Read a lot about the Astron series of linear supplies at
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