use@[EMAIL PROTECTED]
wrote:
> John Fields wrote:
>
>> On Wed, 25 Jun 2008 10:42:54 -0700 (PDT), use@[EMAIL PROTECTED]
wrote:
>>
>>>> Right there in the text "The left side of the circuit uses a
low-power
>>>> dual comparator (MAX9022) to form a relaxation oscillator..."
>>>>
>>>> So, (a) you've been _told_ what's going on, and (b) it's not an
op-amp,
>>>> it's a comparator.
>>> OK, this is clear now, shame engineers use the same symbols for
>>> different things...
>> ---
>> No, the shame lies with idiots like you, who have a do***ent in front
>> of them which clearly states that a _comparator_ is being used as a
>> relaxation oscillator and apparently don't even bother to read it.
>> ---
>
> In fact, some time ago I asked
> on this very newsgroup what is the difference between an op-amp
> and a comparator, and the replies that I received then where that they
> are basically the same thing, that comparators are "optimised for
> switching",
Right. Which means that few comparators work at all where op-amps are
indicated, and none work well. An op-amp is more likely to kind of work
as a comparator, but it'll have its own problems. Review those answers
and see if you weren't told this.
> so due to those idiots (as you put it) back then I have
> been
> missed informed till yesterday. Just goes to show how careful one
> needs to be about info posted here.
It sounds like you're trying to use newsgroups to learn basics.
Newsgroups are good for fill-in, but if you have great swaths of
knowledge to learn you still need to get a good book on the subject
(Like "Art of Electronics") and read it.
> In fact, what our designer wanted
> was a little hysteresis symbol inside the op-amp symbol, which is
> the agreed symbol for comparators with built in hysteresis (?).
> And the datasheet of this particular one, does show the
> correct symbol.
If you stand on a street corner railing about people not using the
latest 'correct symbol' then you'll never get your work done.
Comparators and op-amps are almost universally represented by the same
symbols. If you allow this to confuse you you'll be forever confused.
-- snip --
--
Tim Wescott
Wescott Design Services
http://www.wescottdesign.com
Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html
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