Are log potentiometers marked in any way to indicate their non-linear characteristics?

 

If there is a manufacturer's name and part number on the pot, you can get that information from the web site. You can also use a meter and observe the change in resistance over a few degrees at either end of travel. A log taper will show much more change in resistance at one end than the other.

 

Another quick check is that when you set the potentiometer to the approximate midpoint, the two resistances will be pretty nearly the same value if the pot is linear.

hgmjr

 

A log pot wil have the resistances in a 31/69 ratio since the square root of 10 is about 3.16...

 

Oriental audio pots are marked A for audio. Linear pots are marked B for who-knows-what.

 

Confusing with an Allen-Bradley pot.