Re: Opto Isolator Switching

Oops Chris;

Sorrie, I accidentlly posted it as a reply rather than a new message.

Apologies and thanx for your answer anyway !!

PeterC


--- In CAD_CAM_EDM_DRO@y..., Chris Baugher <cbaugher_yahoo@b...>
wrote:

> On Tue, 3 Dec 2002, Peter Cruickshank wrote:
>
> > I have isolated my limit switches using a TLP540 Opto Isolator,
> > however it appears unable to drive TTL logic directly and it

cannot

> > switch the input of a 7408 NAND Gate without using a 2N2222
> > Transistor in between.
> >
> > Does anyone know if I can drive a ULN2003 Darlington directly

from

> > the isolator without having to use the 2222 as an amplifier ??
>
> Without having datasheets I would just try it and see. Since it's

a

> darlington the input current should be pretty low so I would think
> it should work.
>
> > I am also experiencing some switch bounce and wondered if it

would

> > be preferable to setup an R/C network to turn the signal into a
> > pulse or to dampen the switching ??
>
> Dampen it how, mechanically? Not sure how you would do that since

the

> bouncing is from the switch contacts themselves which are inside

the

> switch. The R/C thing is a standard way to debounce switches and

should

> work fine.
>
> And this is kinda off-topic...
>
> C|