360 degree potentiometer

Thread Starter

Razor Concepts

Joined Oct 7, 2008
212
I am wondering whether 360 degree potentiometers exist, where the wiper can be rotated around continuously. I know you can modify normal potentiometers, but those have a dead band where they were not supposed to rotate. I could use two of these but I would rather just have a single potentiometer. Thanks!
 

Ron H

Joined Apr 14, 2005
7,012
Search for "continuous rotation potentiometer". I got several hits on Google.
 

Thread Starter

Razor Concepts

Joined Oct 7, 2008
212
I tried looking for them, looks like the only manufacturer is ETI systems. But the pricing is a little high ($10+), and the only pot closest to what I want is the EUP1900, with 340 degrees of sensitivity.

Any ideas about a DIY 360 degree pot?
 

Ron H

Joined Apr 14, 2005
7,012
A potentiometer by definition has 3 terminals. One is the wiper. Where would you want the other two terminals connected? 180 degrees apart?
 

ELECTRONERD

Joined May 26, 2009
1,146
There are several digital pots you could use. Just get two tactile switches one for more resistance and one for less resistance and your good to go!
 

Ron H

Joined Apr 14, 2005
7,012
There are several digital pots you could use. Just get two tactile switches one for more resistance and one for less resistance and your good to go!
How do you emulate continuous rotation (360 degrees) with a digital pot?
 
Last edited:

beenthere

Joined Apr 20, 2004
15,808
Any mechanical pot has to have a dead spot or the wiper would short the end terminals.

Limitations like that are why things like shaft encoders exist.
 

Ron H

Joined Apr 14, 2005
7,012
Any mechanical pot has to have a dead spot or the wiper would short the end terminals.

Limitations like that are why things like shaft encoders exist.
It is possible to make a continuous rotation pot in which the stator connections are positioned 180 degrees apart. They may even be available off-the-shelf.
 

ELECTRONERD

Joined May 26, 2009
1,146
How do you emulate continuous rotation (360 degrees) with a digital pot?
If you had a 360 degree pot, when you rotate to the maximum value the wiper would keep turning until you would rotate the wiper the opposite direction. Same with a digital pot, you would keep pushing the tactile switch until it wouldn't go any farther; if you kept pressing on the switch if it was at its maximum value, it would have no effect on the resistance until you rotate it the opposite direction. Thereby decreasing the resistance.
 

Ron H

Joined Apr 14, 2005
7,012
If you had a 360 degree pot, when you rotate to the maximum value the wiper would keep turning until you would rotate the wiper the opposite direction. Same with a digital pot, you would keep pushing the tactile switch until it wouldn't go any farther; if you kept pressing on the switch if it was at its maximum value, it would have no effect on the resistance until you rotate it the opposite direction. Thereby decreasing the resistance.
That sounds like an ordinary pot to me.
Imagine a circular resistance element, with taps 180 degrees apart, and a wiper, but with no stops on the rotor.
 

Thread Starter

Razor Concepts

Joined Oct 7, 2008
212
It is possible to make a continuous rotation pot in which the stator connections are positioned 180 degrees apart. They may even be available off-the-shelf.
Aha, thats what I'm looking for. I think I will try to DIY that with two pots.
 

PackratKing

Joined Jul 13, 2008
843
I see no mention of a precision 10 [ or more ] turn pot............

I used one of these marvelous contraptions [ clarostat ] in construction of my bench power supply, [ 0 - 24 volt, 4 amp DC ] to enhance control over its output that a "normal" 270 deg. 5K pot wouldn't give.

The only other option I am familiar with, is a vernier control, which is nothing more than a calibrated gear reducer, and will allow any number of 360 deg. turns to cover the 270 deg. range of that "normal" pot.
 
Last edited:

ELECTRONERD

Joined May 26, 2009
1,146
That sounds like an ordinary pot to me.
Imagine a circular resistance element, with taps 180 degrees apart, and a wiper, but with no stops on the rotor.
Well, all the normal pots I have stop at the maximum, and minimum points. This would be continuous.
 
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