Which kind of pot rolls evenly off 10 to 0?

[lumgimfong]

I don’t like the pots that act like a on off switch I like to roll gradually from 10 down to zero evenly. Is that a linear taper or audio taper?

[doctorwho]

That would be a linear taper potentiometer. Audio taper is exponential/logarithmic.

[lumgimfong]

ok. Thank you.

[cjj]

Well now, that's an interesting question. What the good doctor said is true, from an electronics point of view. A linear pot varies the resistance linearly from end to end as you turn the shaft.

Unfortunately, our ears are not linear, hence the invention of the audio pot. Our hearing follows a logarithmic curve when it comes to the perception of volume. So log pots were made to try to make turning the volume knob seem to vary the volume linearly, as we perceive it.

Now, as with most things, economics took over and most audio pots these days are not actually logarithmic. Instead, they just put in two different linear sections with different curves which approximate a llog curve.

So, for volume pots, an audio pot will generally provide a more linear response, at least to how we perceive it...

[jps]

... economics took over and most audio pots these days are not actually logarithmic. Instead, they just put in two different linear sections with different curves which approximate a log curve.

The way I hear it most of the time, these newfangled AT pots do a pretty poor job of imitating the real thing.

[cjj]

... economics took over and most audio pots these days are not actually logarithmic. Instead, they just put in two different linear sections with different curves which approximate a log curve.

The way I hear it most of the time, these newfangled AT pots do a pretty poor job of imitating the real thing.

That's basically true, in a lot of applications, since our hearing is not that accurate, most people won't notice, they just "adjust" things until it's what they want.

A "standard" audio taper pot, often called the A10 curve, reaches 10% of the resistance when the shaft is at the midpoint. The attached graph shows a linear taper, an A10 log audio taper and the two-part linear approximation. As you can see, the linear approximation kind of follows the log taper, and isn't too far off for low resistance values. From the 50% point up however, it deviates a fair bit from the desired curve. But, it's better than the linear curve...