So I have need of a 25k-B pot. I have quite a few 50k-Bs laying around so I figured...Is it possible to just put a 25k resistor on the 50k pot legs and have a virtual 25k-B? And if so, what legs do I use, 1 & 3? I assume this wouldn't work with an "A" to "B" designation. I know this has been discussed probably before but I didn't see anything.
50k (47 will do) across lugs 1 & 3, you will affect the taper and this wont necessarily work in all applications, but most.
R1 X R2
---------
R1 + R2
+1 to the above.
If you're interested how the taper is affected (and more), read this.
http://www.geofex.com/article_folders/potsecrets/potscret.htm (http://www.geofex.com/article_folders/potsecrets/potscret.htm)
You could also do a 25k between lug 1 & 2 and a 25k between 2 & 3. That would keep the taper a bit truer to linear.