What is an easy way to get 7-7.2vdc from an scavenged atx psu? I had thought about using a lm317 but I'm going to need at least 5-7 amps of current, and the 12v-5v split just sounds like a really bad idea...any thoughts?
closed as too broad by Chris Stratton, Dmitry Grigoryev, awjlogan, Elliot Alderson, Finbarr Sep 28 '18 at 16:37
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A good "green" solution would be to design a suitable DC to DC converter to step the 12V down to 7.2V. There is a good bit of information for assistance in designing a suitable DC to DC converter at a number of manufacturer web sites but the one that comes immediately to mind is the one here at this link. The web bench tool offers a plethora of design ideas as possible solutions for you.
I do have a sneaking suspicion that due to your use of a re-captured ATX power supply that you are looking for a solution that does not involve going off to design and build a surface mount PC board. If that is the case then you may want to consider the use of a pre-made POL (point of load) module to do the DC/DC conversion. The picture below shows what one of these looks like.
These POL type modules support a range of input voltages and can have their output voltage set through the use of a resistor or two.
Another possible solution is to consider looking into available AC to DC type power supplies and foregoing the use of the ATX power supply. This is likely to be an overly expensive solution so it may be desirable to take a look at what you need the 7-7.2V for and see if there is a way to effectively rethink the problem so that you can actually use +12V or +9V for your design, both of which are way way more readily available in off the shelf product.