[sdiy] Resolution of analogue potentiometers?

[cheater cheater]

I wonder how good the gradient is in a carbon-deposition
potentiometer. Is it going to be perfectly smooth or is there some
sort of stepping still?

Cheers,
D.

On Tue, Feb 12, 2013 at 10:50 AM, Bob Weigel <sounddoctorin at imt.net> wrote:
> On 2/11/2013 11:51 PM, Ove Ridé wrote:
>>
>> Consider a wirewound potentiometer:
>> http://upload.wikimedia.org/wikipedia/commons/c/c3/Pot1.jpg
>> By its nature it has a ribbed surface and the wiper will tend to be
>> attracted to discrete values. Obviously you don't use those in audio,
>> but if smaller potentiometers of some type has a similar composition
>> that might give a similar effect.
>>
>> However, it's more likely that precision means the minimum distance
>> you can move the wiper due to surface retention inside the pot.
>>
>> On 12 February 2013 03:10, Paul Anderson<wackyvorlon at me.com>  wrote:
>>
>>>
>>> I'm not sure I understand your question? They're analog, so the change is
>>> continuous.
>>>
>>> --------
>>> Paul Anderson -- VE3HOP
>>>
>>> On 2013-02-11, at 9:06 PM, Michael Zacherl<sdiy-mz01 at blauwurf.info>
>>> wrote:
>>>
>>>
>>>>
>>>> Hi, I thought this already has been discussed but couldn't find the
>>>> thread:
>>>> How's the actual resolution of the resistive track of an analogue
>>>> potentiometer
>>>> specified? On some data sheets I read "<  0.1°" for a rotative pot.
>>>>
>>>> for instance,
>>>> in terms of pitch control over a very wide range, using a multiturn pot
>>>> or trimmer,
>>>> where are the limits for the resistive tracks and pots at all?
>>>> Technically speaking, leaving practical aspects aside for a moment.
>>>>
>>>> Thanks, Michael.
>>>>
>>>>
>>>>
>
> Actually wirewound resistors can be used in certain audio applications fine.
> I wouldn't recommend for a pitch control but for volume they're often fine.
> They're a make before break switch in essence with however many steps there
> are in the number of winds.  Volume pedals etc. they will leave no
> discernable difference probably.  They may last longer than carbon trace
> units also.
>
> But anyway the resolution of other pot types has more to do with how
> incrementally they can be moved.  There is always a certain amount of
> friction in the mechanical aspects of the units.  So you have to put a
> certain torque on the shaft to get it to move.  And this creates a momentum
> that will cause it to turn some minimal angle of course.
>
> Otherwise the resolution limits would fall into the realm of the
> molecular/atomic structure and how it interfaces with the wiper :-).  Which
> is for all intensive purposes infinite resolution in any application known
> to man probably ...
>
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