[sdiy] center tapped pots?

[Andre Majorel]

On 2007-04-10 13:37 -0700, Dave Manley wrote:
> Andre Majorel wrote:
>
> >Or as shown below, run two resistors of equal value from the
> >wiper, one going to the CW lug, one going to the CCW lug.
> >
> >  http://www.elby-designs.com/documents/tailoringpotentionometers.pdf
> 
> This is a good paper, but the warnings in the last paragraph should 
> perhaps be put at the start: the resistance across the pot with the 
> extra resistor(s) can be much lower than the original pot depending on 
> the curve you're trying to achieve.  As they say in the paper: the 
> surrounding circuit may not like this much.

Also the value might not be stable with temperature. If you use a
carbon pot and metal film resistors, part of the circuit has a
tempco of 1000 PPM/K and part of it has a tempco of 100 PPM/K. Rr
/ Rp changes with the temperature.

-- 
André Majorel <URL:http://www.teaser.fr/~amajorel/>
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