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The LM317 is an excellent voltage regulator.sam2 said:I built this power supply **broken link removed** for a 9v am radio and it has a noticable hiss over the 9v battery I was using. Can I do anything to clean it up or should I try another power supply.
audioguru said:The LM317 is an excellent voltage regulator.
Maybe yours has its wires too long so it oscillates.
Did you use all the capacitors it shows?
That makes no sense, you can't have a 300mAh transformer, do you mean a 300mA transformer?sam2 said:The transformer is only 12.6 v 300 mah.
I doubt they are 23,000:mu:F capacitrtors; it isn't a standard value.I assumed that 22000uf value was a typo.
I have a couple of 23000uf caps and they are 2" in dia and 2'' high!
Hero999 said:That makes no sense, you can't have a 300mAh transformer, do you mean a 300mA transformer?
With a 300mA transformer the maximum current you can safely draw from the regulator is 212mA; how much current does your AM radio draw?
I doubt they are 23,000:mu:F capacitrtors; it isn't a standard value.
Anyway 22,000:mu:F is pretty excessive for only 212mA, you only really need 2,200:mu:F I would 3,300:mu:F to be on the safe side. Even so using larger capacitors is unlikely to do any harm so I don't see the problem.