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I've been making an audio amplifier, it works well so far after getting the correct components. I'm using a 10K potentiometer with switch for the volume but I've got a problem. The potentiometer increases resistance as I rotate clockwise... I need it to be the opposite, at the moment when rotating clockwise it works like this:

Off - 0 -> 10k

But I want it to be like this:

Off - 10k -> 0

If there a way to reverse the resistance, or have I purchases the wrong pot?

Thanks for your help :-) Ben

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2 Answers

up vote 7 down vote accepted

Normally a potmeter has three connections. The middle is the wiper which moves over the resistive path, from the left pin to the right one when rotating clockwise. Swap the left and right pin and you should be OK. Important: be sure that it's a logarithmic potmeter instead of the regular linear ones.

edit
I read that the resistance increases if you rotate clockwise, and that you want the reverse. I don't know what the surroundings of the potmeter look like, but for a volume control you normally want to increase the resistance (between the left pin and the wiper) when rotating clockwise. If for some reason you want the reverse you don't want a logarithmic potmeter, but an anti-logarithmic one, which is much rarer.

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I think it's linear... although the link (in my question) mentions both log and lin in the spec :S – Ben Everard Feb 17 '12 at 11:21
@Ben - you can easily check whether it's lin or log. Put the wiper in the halfway position and measure the resistance to one end. If it's 5k then it's lin, if it's far less or far more it's log. – stevenvh Feb 17 '12 at 11:31
I measured the resistance at halfway yesterday and it was about 4.6k.. but then even at full it was only 8.9k (something like that, certainly not the full 10k(, so it at halfway it's certainly about 50%. Does this mean swapping the left and right won't work? – Ben Everard Feb 17 '12 at 11:35
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@Ben - Swapping will work, but you'll get poor volume control: the volume will increase very fast in the beginning and only a little at the end of the rotation. A log potmeter will have a smoother response. – stevenvh Feb 17 '12 at 11:38
Many thanks for your answer, I tried it and it does work, reducing resistance as I turn clockwise. This will do me for now, thanks again :-) – Ben Everard Feb 17 '12 at 14:13
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up vote 3 down vote

Swap the two connections to the ends of the track.

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Thanks for your answer Leon :-) – Ben Everard Feb 17 '12 at 14:13

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