[sdiy] SN 76495

[Tim Parkhurst]

On 6/28/06, Seb Francis <seb at burnit.co.uk> wrote:
> Some quick answers (probably you will get many others) ..
>
> bill bigrig wrote:
> > Howdy,
> >
> >  I just dug up a SN 76495 that i bought at radio shack
> > eons ago and figured i'd try to build a module. I
> > think it's a little brother to the SN 76477. SO!
>>
> > How do I block a negative voltage from an input?
> >
>
> A diode in series (you will 'lose' 0.7V across the diode though)
>
> Seb
>
Actually, an op amp with a diode in the feedback loop will give you
the same effect, but without the 0.7V drop. You might even be able to
combine the 'block negative voltages' and 'invert CV' in a single op
amp stage. Look up "precision rectifier" or Jim Patchell's "Ideal
Diode tutorial" for more info.


Tim (getting a lot of mileage out of the " key today) Servo
-- 
"Imagination is more important than knowledge." - Albert Einstein