Lowest impedance for ADC?

[Demon]

Microchip often mentions 10K as the maximum recommended value, but I had an incident a short while ago with a PIC that didn't want higher than 2K (I think) in the datasheet.

I'm in the process of buying pots and my current samples with 20% tolerance just isn't cutting it; some don't all go down to exactly 0V, or won't reach 5.0V. This of course affects ADC readings; some go down to 0 and up to 255, and some don't.

1. Would a lower resistance pot (like 1K-2K) be easier/cheaper to get tighter tolerances?

2. Is there a physical work-around for "weak" pots? (hardware trick)

3. Would lower resistance pots actually be "better" for ADC? I remember Richard saying a 1K pot could "in theory" have 1 ohm resolution at 10 bits (or something to that effect).


If tight tolerance pots are just too expensive, one alternative I was thinking of one of those complicated formulas to move the goal posts so to speak:

- actual ADC reading on a sample pot: 4 to 1018

- formula would use range between 4 and 1018, and stretch that out to 0 to 1023

Does this make sense?

This flight simulator really wants a range of 0 to 1023 to be able to use the full range of motion on a control (imagine a choke that's always partially ON, or a flap, not good).


EDIT:

I'm reading this to see if I can make use of that info:

https://www.picbasic.co.uk/forum/sho...to-a-new-range