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HELP REQUIRED! run battery gadget via USB.

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I have a set of headphones that I use regularly with my PS3. They plug into a control box thats fed from the optical output of the PS3. Unfortunately it's run via 2 AA batteries, and it's costing me a fortune! Rechargeable batteries don't seem to last long enough.

I'm looking to create something like this to power it, but it's been years since I did electronics at college, so I've forgotten most of what I have learnt!

I'm good at the actual building side of things, I'm just no good at designing circuits, so I'm hoping someone on here can help!



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The important two capacitors are not optional and are missing from the Instructables circuit.

Both circuits have the value of R1 too high. It must be 120 ohms or less for an LM317. It can be 240 ohms for a more expensive LM117.
When the value of R1 is too high then the output voltage rises when the load current is low.


2 AA batteries is only 3 volts. 5 volts may be too much for your little device. Why do you have such a weird headphone setup? What's the point using the optical jack from the PS if you can't get power? You could use a simple 3 volt regulator.
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