Resolved: [sdiy] 555-based ADSR that refuses to work with 9v

[Karl Ekdahl]

Thanks, the diode did the trick. I'm still a little
confused as to why other people made it work with 5v,
but if it works it works...

Karl

--- René Schmitz <uzs159 at uni-bonn.de> skrev:

> Hi Karl and all,
> 
> Karl Ekdahl wrote:
> > Maybe i'm really confused, i've rewired the
> circuit 3
> > times on a breadboard and my conclusion is this:
> the
> > circuit triggers fine applying a +9v trig at the
> > junction of the 10n and 10k, though while trying
> to
> > trig it from the "actual" trigger it works
> spordically
> > every now and then. As i understand it, after
> > fiddeling a little, the 10n cap gets a charge from
> the
> > trig that it doesn't allways gets rid of before
> the
> > next trig thus not retriggering. 
> 
> Try a diode at the base of the third transistor,
> configured like the 
> protection diode at the input. Maybe there is really
> an action from the 
> reverse breakdown, helping to get rid of the charge.
> Which wouldn't be 
> effective with a lower operating voltage.
> 
> Cheers,
>   René
> 
> -- 
> uzs159 at uni-bonn.de
> http://www.uni-bonn.de/~uzs159
> 
> 
>