[sdiy] voltage control primer?

[harry]

Yes... and No!

The voltage control pin of the 555 is active only over a small range... (maybe
10:1)
not very musical I'm afraid.

You 'may" or may not have to buffer voltages from that point. You really
want to build a musical VCO which can be controlled over a wide rande
(1000:1 typical).  See the EFM site for some schematics of simple VCO's.

The 555 can be voltage controlled by sourcing the capacitor through a current
source instead of a resistor... but it isn't any easier than a regular VCO once
you
do that !

H^) harry

Alex Dickey wrote:

> they're starting to stack up.  i now have three sound making devices that
> i'd like to make voltage controllable, but not a clue how to do it.  can
> someone give a run down what you need to VC stuff?  at least some sort of
> beginning?  link?
>
> to specify this a little, i just got a bag full of 555s.  obviously, there's
> a VC pin.  now, if i just feed that pin random voltages, is that it?  do i
> need some sort of buffer or something?
>
> thanks,
> alex
>
> "wha-na-na-na-na-na-na-na-na-na."
> -j. caletti