General CV question (Re: [sdiy] Paia MIDI Fader)

[sarth at sarth.net]

Hi,

I am a little new and have 2 questions for the list ...

1) Does anyone have a favorite place to buy variable-resistance sensors?
I found a light-sensitive photocell that varies it's resistance in response
to illumination at radio shack, but that's about it.

2) I think I'm having trouble grasping a basic concept:

There seems to be 2 different types of inputs that accept variable voltage
or resistance. 

The back of most MIDI synths have a CC pedal input, and I presume that pedal
is varying the resistance of a signal passed through it. However CV inputs
that want a 0-5 V range seem to operate on a related but different
principle, in which power is provided to the pedal and the voltage is
measured across 2 other connectors?

The paia midi fader kit illustration shows it measuring variable voltage
sources AND having a variable resistor hooked up to 3 inputs simultaneously.

I want to buy sensors from infusion systems ( http://infusionsystems.com )
and hook them up to the paia midi brain. Someone told me I'd have to rig up
a voltage divider circuit and sent me the url for this peavey 1600 mod:

http://music.columbia.edu/%7Edouglas/pc1600mod/pc1600mod.html

I just don't understand the distinction between these types of variable
resistance/voltage circuits. Any clarification would be greatly appreciated.

-- Sarth