On 11/12/2011 7:21 PM, John Fields wrote:
On Wed, 9 Nov 2011 12:31:43 -0800, wrote:



. E1 -0.621V
. | 0.621V R3 /
. [Ra] / +-[10k]-+
. | / R2 | |
. +-+--[10k]--+--|-\ |
. | / |-+
. [Rb] / +--|+/
. | 0V |
. GND GND

"OK", you may say, "but what on Earth does that have to do with a 50k
pot feeding a 10k load?"


If we make a table of changes in output voltage as a function of
successive 5kohm changes in pot resistance, we'll have:

. R V dV
.--------------------
. 50k 1.000 0.379
. 45k 0.621 0.177
. 40k 0.444 0.103
. 35k 0.341 0.069
. 30k 0.272 0.050
. 25k 0.222 0.040
. 20k 0.182 0.036
. 15k 0.146 0.035
. 10k 0.111 0.042
. 5k 0.069 0.069
. 0k 0.000 -----

You can see from dV that the change in voltage isn't very linear.

Our hearing is more or less logarithmic, so it might be about right.

Further more most volume pots in audio are logarithmic.