On Mon, 26 Nov 2001 15:32:51 -0500 Douglas Butler writes: > Note that a 10K pot will have an output impedance of 5K if the wiper > is > set to the middle. The output impedance will be lower as the wiper > moves away from the middle. > Wouldn't that be 2.5K? > Also if you are not using the full resolution of the A/D you can > scrimp > on capacitor size or pot impedance. If it is a 10 bit pot you are > using > only the most significant 8 bits of, you have a factor of four to > fudge > with. > > The effect of a high source impedance feeding the A/D is > nonlinearity. > If it is just a light dimmer or volume control, you may not really > care > if it is a little nonlinear. Also seems like there'd be drift in the nonlinearity due to bias current changing with temperature. Harold FCC Rules Online at http://hallikainen.com/FccRules Lighting control for theatre and television at http://www.dovesystems.com ________________________________________________________________ GET INTERNET ACCESS FROM JUNO! Juno offers FREE or PREMIUM Internet access for less! Join Juno today! For your FREE software, visit: http://dl.www.juno.com/get/web/. -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu