To use a 10turn pot I have to use an 8 tooth gear with 0.8 pitch which does not exist. The smallest gear I found is 15 tooth. For this reason I was considering a three turn pot. My concern is more about the supply voltage to the potentiometer. A small variation is the supply will cause the position to be inaccurate.

 

why use a gear? just use part of the pots range. only one turn, with a mechanical stop.

 

Personally I would have used a 5k minimum, your resolution will also be a bit finer, but if the input is a micro then the cable and input impedance should not have any effect as far as I see it.
Max.

Hi,

The datasheet of the PIC18F4550 states that:

The maximum recommended impedance for analog sources is 2.5 kΩ. (page 264).

I have a continuous turn potentiometer with 1% linearity. The value is 1Kohms. Do you think it will fit for this application? What exactly are the drawbacks of using a small impedance inputs at the ADC?

 

I think as long as you do not exceed the 2.5k you will be OK.
Max.

 

Hi again,

A quick question, are wirewound potentiometers good for position sensing?

 

Yes, but they generally do not go as high in value.
Max.