Not really. Most multi-turn trimpots have enough backlash in the drive
that their resolution is no better than a single-turn pot... just a
lot more tedious to adjust.
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Resolution refers to the smallest increment of resistance achievable
in the pot, and has nothing to do with backlash. Of course, if you
go too far and then have to go even farther forward to back up to
whre you need to be, it's inconvenient, but the resolution of the
pot is still the the resolution of the pot,. A wirewound pot,for
example, will have a resolution depending on the pitch of the helix
the resistance wire is wound to, while the resistive element of a
cermet pot will have essentially infinitesimal resolution. Whether
that resolution can be achieved will be largely determined by the
'stiction' of the drive, but there will be no fixed resolution limit
as exists in a normal wirewound pot.
I think what the OP is referring to is the _sensitivity_ of the pot,
which can be described as the total resistance of the pot divided by
the total angle of rotation of the shaft. That is, a single turn
10k pot with 300 degees between stops will have a sensitivity of:
Rt 10kR
S = ------- = ------ = 33.33 ohms per degree
theta 300°
While a 25 turn 10k pot will have a sensitivity of
Rt 10kR
S = ------- = ------- = 1.11 ohm per degree
theta 9000°
Which means that if the best you can do, by hand, is a one degree
crank, with a 25 turn pot (with a resolution great enough to allow
it) you'll be able to resolve 1 ohm out of 10k, which is 0.0111%,
while with a single turn pot with 33.3 ohms out of 10k, that's
0.333%.
So, for the same angle of rotation, the 25 turn pot will have a
sensitivity 30 times greater than that of the single turn pot.