potentiometer 101- basic explaination needed

[bent]

HI everyone,
i just realize that not all pot are having voltage passing throught, i look at my SHecho yesterday, and find that the 2x 50K doesn't have voltage passing in them (maybe it's my meter that isn't fast enough to read?), i look at my big muff, and realize that one pot have voltage going in it, the other doesn't seem to...

can someone give me a basic overview on why some are using voltage and other don't...

thank you

bent

[wampcat1]

A pot is like having two different resistors...one from lug one to lug two, and one from lug two to lug three. These can both be varied and as one gets bigger, the other gets smaller (search: voltage divider).

Using just two lugs is just like having one variable resistor.

So, for example, if you have a 100k pot, you can (basically) get any resistance from 0k (which is called continuity) all the way to the value of the pot, in this case 100k.

That said, resistors do different things in a circuit. They won't always be regulating a ton of voltage but you will probably have at least a LITTLE voltage on them at different places, but this isn't as important to remember if you are new to circuits. The real thing to figure out is what all the different components in a circuit are doing when connected in certain ways to form a circuit.

Start at geofex.com, muzique.com, the wiki (http://www.diystompboxes.com/wiki/ ) and the faq pages as listed at the top of this page. If you are still having problems, buy my books - they'll explain everything in 'laymen's' terms.
Thanks,
Brian

[R.G.]

can someone give me a basic overview on why some are using voltage and other don't...

The voltage is there, but it's too small for your meter to read, or possibly you're trying to read AC signal voltage on DC meter setting.

For how pots work, read "The Secret Life of Pots" at GEO, http://www.geofex.com.

Pots are used either as three terminal devices to divide either current or voltage, and also as two-terminal devices as a variable series resistor. The article explains both.

I think you were trying to measure voltage across a dual volume control. Unless you have quite large signals, a simple DMM will not read these very well. You have to be on the AC scale and then in the lowest voltage ranges most of the time.

[bent]

thank's to both of you, i will try it.....

bent