Non-linear pot, more precise in middle
Non-linear pot, more precise in middle
(OP)
Hi,
I took apart a potentiometer that I thought was a simple rheostat. The max resistance between an outer leg and the middle leg was higher than the constant resistance between the two outer legs.
It turns out to have two resistive strips inside and a wiper that connects the two. Each end of the outer strip is connected to an outer leg and the inner leg is connected to one end of the inner strip. As the pot is turned the position where the two strips are jumped together changes.
The strips are of different resistances per length and the pot is non-linear. I notice it appears to have less precision as the wiper approaches the ends.
If there might be another reason why this pot would be designed this way, please let me know what you think. My question is: what would I call a pot like this if I were looking to order one? I've seen precision, and logarithmic, but non-linear alone wouldn't exactly describe this behavior (higher precision in one area)...
Thanks,
Dave
I took apart a potentiometer that I thought was a simple rheostat. The max resistance between an outer leg and the middle leg was higher than the constant resistance between the two outer legs.
It turns out to have two resistive strips inside and a wiper that connects the two. Each end of the outer strip is connected to an outer leg and the inner leg is connected to one end of the inner strip. As the pot is turned the position where the two strips are jumped together changes.
The strips are of different resistances per length and the pot is non-linear. I notice it appears to have less precision as the wiper approaches the ends.
If there might be another reason why this pot would be designed this way, please let me know what you think. My question is: what would I call a pot like this if I were looking to order one? I've seen precision, and logarithmic, but non-linear alone wouldn't exactly describe this behavior (higher precision in one area)...
Thanks,
Dave





RE: Non-linear pot, more precise in middle
Or maybe I'm missing something...
Dan - Owner
http://www.Hi-TecDesigns.com
RE: Non-linear pot, more precise in middle
That's one place where a nonlinear pot with a sensitive middle would make sense.
Mike Halloran
Pembroke Pines, FL, USA
RE: Non-linear pot, more precise in middle
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Non-linear pot, more precise in middle
Have a look at the ALPS website. They make an enormous variety of pots.
ht
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Sometimes I only open my mouth to swap feet...
RE: Non-linear pot, more precise in middle
One question I still have on this subject:
Is there a term for the "total resistance" of these types of pots? When I say "total" I am refering to the fixed end-to-end resistance, not the minimum or maximum variable resistance.
Thanks,
Dave
RE: Non-linear pot, more precise in middle
"This is a 100K pot"; means the end to end resistance.
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Non-linear pot, more precise in middle