"Dave Plowman (News)" wrote in message
...
In article ,
D Yuniskis wrote:
I've got a (Vellerman) PWM device which is DC controlled. I'd like to
use it such that it fades up to max when a simple DC switch is made,
then fades out when it is broken. I can get it to do this using a
simple RC circuit - but the 'law' of the fades isn't as linear as I'd
like. Any clever way of doing it?
Constant current source into a cap.
The constant current source into the cap is easy enough - but the constant
current load?
--
*I used to have an open mind but my brains kept falling out *
Dave Plowman London SW
To e-mail, change noise into sound.
You might be able to get away with using a simple 555 timer chip. The ramp
produced across the timing cap is pretty linear AFAIR
Arfa