Using DMM to answer Q's quick

Started by petemoore, August 22, 2005, 10:56:43 PM

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petemoore

Getting used to using the DMM for answering questions is a quick way to figure out what's up with R's and Pots.
 Set Dmm to resistance range of 20k
 Figure the 1k pot wafer [lugs 1 and 3 connect ends] as a resistor, to which you can put another resistor, and disregard the wiper for now.
 Take a 1k resistor and add it to the pot
a  One R lead On an outside lug, now the max R is 2k and min R is 1K of the seriesed 1k pot and 1k resistor.
b  across the pot, one lead on each outside lug, 1k divided by 1k is .5k, now the pot is like a 500ohm
 Clip a lead of the DMM to the wiper, other lead to outside lugs and twist the pot to the middle range [center pos.], if both sides read 500ohm or thereabouts, it's a linear pot.
 resistors in series, add to R value: 1k parallel 1k+2k
 in parallel, it's the opposite...divide, 1k series with 1k = .5k + 500ohm
Convention creates following, following creates convention.