how do you tell the difference between a log and linear pot?

[talking_goat]

how do you tell the difference between a log and linear pot just from looking at it??

[black mariah]

IIRC, audio taper pots are marked with an A and linear with a B. So the value would be like A500K or B250K. Other than that, I don't know.

[travissk]

Sometimes the codes can get a little confusing... the sure-fire way to tell is to hook up your meter, set it to ohms, turn the pot and see how the numbers change

[travissk]

I think I should mention how it gets confusing:

Once upon a time, there was a code for pots. I think it went like this:
Linear - A
Audio/Log taper: C
Reverse Log: F

Then, a great evil descended on civilzation. Wars were fought, and the forces of good prevailed, but at a great cost. Villages were in ashes, heroes had fallen, and the potentiometer codes had changed to the modern ones:
(Sorry, I've been up for way too long  :shock:)

Linear - B
Audio/Log: A

So it's not too much of a problem, until you find a pot that's marked with an "A." Is it a new log taper, or is it an old linear taper? If you're using newly-made pots, just go with "A=Audio, B=Linear" and you should be fine. If you're cannibalizing old stuff, use the meter. There might be a trick someone knows to identifying them, but I usually just check.

[Jason Stout]

Turn the pot to the geographical mid-point, measure from mid lug to each outer lug (seperatly) If the values are equal your pot is linear. If they are nowhere close, its logarithmic.