Searching \ for 'Opto Couplers etc.' in subject line. ()
Make payments with PayPal - it's fast, free and secure! Help us get a faster server
FAQ page: www.piclist.com/techref/index.htm?key=opto+couplers+etc
Search entire site for: 'Opto Couplers etc.'.

Truncated match.
PICList Thread
'Opto Couplers etc.'
1998\01\16@202346 by Bill (WL) Boulton

flavicon
face
This is for anyone contemplating using opto couplers or similar devices in
projects.

   "USE ONLY AS A LAST RESORT!"

Why?  They are SLOOOOOOOOOOW!

So before you design them into a project, go to SIEMENS web site
<http://www.siemens.com>, find the opto app notes section and get app notes
1, 2, 4 and 5 as a minimum. They are in .PDF format and although small,
ther is enough info there to put you on the right track.

Good luck with your projects,
Bill

1998\01\16@203622 by DREITEK

picon face
In a message dated 98-01-16 20:24:07 EST, you write:

<<
This is for anyone contemplating using opto couplers or similar devices in
projects.

    "USE ONLY AS A LAST RESORT!"

Why?  They are SLOOOOOOOOOOW!

So before you design them into a project, go to SIEMENS web site
<http://www.siemens.com>, find the opto app notes section and get app notes
1, 2, 4 and 5 as a minimum. They are in .PDF format and although small,
ther is enough info there to put you on the right track.

Good luck with your projects,
Bill >>


They're not all so slow.  The NEC PS9601 has a propagation delay of 50ns.  You
can commonly find them in the 1-8 microsecond range.

Dave Duley

1998\01\17@004005 by Gabriel Gonzalez

picon face
>This is for anyone contemplating using opto couplers or similar devices
in

>projects.

>

>    "USE ONLY AS A LAST RESORT!"

>

>Why?  They are SLOOOOOOOOOOW!

>

Not necesarily,



maybe most commercial ones are, but there are also very (extremely) fats
optical sensors and transmitters. Just imagine the speeds of fiber
optics comms.



Gabriel

TGO Electronica

Mexico

______________________________________________________
Get Your Private, Free Email at http://www.hotmail.com

1998\01\17@153230 by John Payson

picon face
> maybe most commercial ones are, but there are also very (extremely) fats
> optical sensors and transmitters. Just imagine the speeds of fiber
> optics comms.

In project at work, I frequently run about 50kbsp synchronous through
the (reasonably-priced) optoes we use.  Pushing things to 250kpbs works
just fine with these optoes, but since the application gets no further
benefit, I prefer to keep the safety margin I get with the slower speeds
(at the faster speeds the signals look pretty mungey).  I don't know
off-hand what type of optoes we're using, but this is with what the parts-
selection guy regards as relatively "vanilla" optoes; the slightly more
expensive optoes can operate at 500kps with decent-looking waveforms.

1998\01\17@154024 by Jim Ham
flavicon
face
I feel that this is an over-simplification. HP and others have optos that
have bandwidths as high as 10 Mbits/sec. Perhaps in your application this
is SLOOOOOOW. It's true that if you pick up an opto that is constructed
with an led and  photo-transistor (or worse, a photodarlington), it will be
sloooow. As soon as you substitute an opto that is constructed with a PIN
diode and transistor instead of a phototransistor, the bandwidth goes up to
about 1Mbit/sec. So you pick your performance and pay the price....

Regards, Jim Ham

At 08:23 PM 1/16/98 -0500, you wrote:
{Quote hidden}

Jim Ham, Porcine Associates
(415)326-2669 fax(415)326-1071
"http://www.porcine.com"

1998\01\17@160425 by Bill (WL) Boulton

flavicon
face
Ladies & gentlemen,

I'd like to make a couple of points for clarification:

1. My comments were to those of us who don't have big budgets and clients
to pay for our fun and games. It is intended for those who have to buy (at
least on occasions) over the counter at the local Tandy or DSE. I don't
think I am the only one in that boat.

2. Lazer & fiber optics comms have less in common with opto couplers than
does chalk with cheese. They aren't in the same league by any stretch of
the imagination.

It is easy to assume that because optical comms is fast, all optical
connections are fast. This is not so and probably to a greater extent than
most realise. The app notes I mentioned provided me with the only
explanation of device characteristics I have been able to find. Text books
and most (all) data sheets are useless and down right misleading.

Bill

1998\01\17@180226 by Steve Baldwin

flavicon
face
> In project at work, I frequently run about 50kbsp synchronous through
> the (reasonably-priced) optoes we use.

The vanilla opto's seem to get a bit of a rough deal through
misapplication.
The trick is to remember that it is a transistor and treat it the same as
you would any other transistor that you want to get good speed out of.
Keep the collector current as low as needed.
Putting a resistor (100k) from base to ground gives a cheap and dramatic
speed improvement.

Steve.

======================================================
 Very funny Scotty.  Now beam down my clothes.
======================================================
Steve Baldwin                Electronic Product Design
TLA Microsystems Ltd         Microcontroller Specialists
PO Box 15-680                email: spam_OUTstevebTakeThisOuTspamkcbbs.gen.nz
New Lynn, Auckland           ph  +64 9 820-2221
New Zealand                  fax +64 9 820-1929
======================================================

More... (looser matching)
- Last day of these posts
- In 1998 , 1999 only
- Today
- New search...