On Wed, Nov 11, 2009 at 1:32 AM, Mark Rages wrote:
>
> Now this is an interesting statement to me. I thought the whole point
> of a Schmitt input was to give the input a little "snap" and therefore
> increase the rise/fall times.
s/increase/decrease/
--
Mark Rages, Engineer
Midwest Telecine LL
On Wed, Nov 11, 2009 at 1:14 AM, gene glick wrote:
> Oh, btw,
> this opamp used drives a schmitt trigger - sort of a poor mans
> comparator. Same problem though, with the slow edge rate fooling it.
>
Now this is an interesting statement to me. I thought the whole point
of a Schmitt input was to
Martin Maney wrote:
>
> Nah. You should use a good comparator with controlled hysteresis. An
> opamp, any opamp, makes at best a mediocre comparator.
Actually, it worked! Not sure why I didn't think of it earlier, but I
threw the circuit into simulation to see. By cranking the gain up from
On Tue, 2009-11-10 at 13:15 -0500, Ethan Swint wrote:
> I just did a git fetch & build today from Peter's GL branch - many kudos
> again! - but I'm getting a few "features" in my zooming activity. The
> first is reproducible by
> 1) open PCB layout
> 2) Swap application focus
> 3) Use Alt+TAB t
On Tue, 2009-11-10 at 22:06 +, Kai-Martin Knaak wrote:
> On Tue, 10 Nov 2009 18:14:40 +0100, Stefan Salewski wrote:
>
> > I think it was
> > shut down some months ago as announced in this list, and on
>
> IIRC, it was not shut down but suffered a change of policy. Mere user
> mortals like y
On Nov 10, 2009, at 10:58 AM, carzr...@optonline.net wrote:
> This particular opamp is opa2132 from TI, and has slew rate of
> about 20 V/us.
FET input. Makes a difference.
An opamp hits its slew rate when its differential *input* stage is
driven to its limit. For a bipolar input without em
> I vote to keep it. Besides the educational value, the great postings
> about electronics on geda-user are archived and searchable via
> Google. That means that folks who are searching on keywords related
> to electronics will come across the gEDA project. The high level of
> the disucssions o
On Tue, 10 Nov 2009 13:15:38 -0500, Ethan Swint wrote:
> I just did a git fetch & build today from Peter's GL branch - many kudos
> again! - but I'm getting a few "features" in my zooming activity. The
> first is reproducible by
> 1) open PCB layout
> 2) Swap application focus
> 3) Use Alt+TAB to
On Tue, 10 Nov 2009 18:14:40 +0100, Stefan Salewski wrote:
> I think it was
> shut down some months ago as announced in this list, and on
IIRC, it was not shut down but suffered a change of policy. Mere user
mortals like you and me are not allowed to post to the list any more.
> www.gpleda.o
On 11/10/2009 12:08 PM, Peter Clifton wrote:
>
> To update without re-fetching the whole thing, this might / might not
> work:
>
> git fetch
> git reset --hard origin/before_pours
>
>
This works fine for me.
-Ethan
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geda-user mailing list
geda
On Nov 10, 2009, at 6:31 AM, Andy Fierman wrote:
> Using opamps as comparators can be tricky.
...and problematic. Comparators are designed to run in saturation
pretty much all the time in open-loop circuits, usually driving some
form of logic circuit. They are also designed for fast recov
There is a new development snapshot available ...
http://gnucap.org/devel/gnucap-2009-11-10.tar.gz
Optional plugin files:
http://gnucap.org/devel/gnucap-2009-11-10-models-bsim.tar.gz
http://gnucap.org/devel/gnucap-2009-11-10-models-jspice3-2.5.tar.gz
http://gnucap.org/devel/gnucap-2009-11-10-mod
On Tue, Nov 10, 2009 at 12:44 PM, Dave McGuire wrote:
> On Nov 10, 2009, at 1:04 PM, John Griessen wrote:
>> PS I enjoy the OT's here. They're not so far out, really.
>
> Me too..
>
> -Dave
Me three.
Regards,
Mark
markra...@gmail
--
Mark Rages, Engineer
Midwest Telecine LLC
markra..
On Nov 10, 2009, at 1:04 PM, John Griessen wrote:
> PS I enjoy the OT's here. They're not so far out, really.
Me too..
-Dave
--
Dave McGuire
Port Charlotte, FL
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I just did a git fetch & build today from Peter's GL branch - many kudos
again! - but I'm getting a few "features" in my zooming activity. The
first is reproducible by
1) open PCB layout
2) Swap application focus
3) Use Alt+TAB to return focus to PCB.
4) Use scroll wheel to zoom
The menu bars a
Dave N6NZ wrote:
If
> geda-user were split I would probably subscribe to gschem-user,
> pcb-user, geda-dev, geda-chat (for general electronics and what not) and
> not geda-sim.
>
> So, maybe split the list, but I wouldn't want to chase any of the
> current posters off.
That's such a small fr
Stuart Brorson wrote:
> Hi --
>
>> I wonder if there is a better place to ask simple electronics questions
>> like OpAmp behaviour?
>>
>> I think newsgroup sci.electronics.design is not too bad?
> [.]
>> What do you think?
>
> Just my $0.02.
>
> I am always pleased by the high level of e
Stuart Brorson wrote:
>
> I am always pleased by the high level of electronics knowledge
> displayed by the folks on this list. The contributions are very
> interesting and educational.
>
Agreed. I'm both pleased and very, very grateful.
> I vote to keep it. Besides the educational value, t
Hi --
> I wonder if there is a better place to ask simple electronics questions
> like OpAmp behaviour?
>
> I think newsgroup sci.electronics.design is not too bad?
[.]
> What do you think?
Just my $0.02.
I am always pleased by the high level of electronics knowledge
displayed by the fol
On Tue, 2009-11-10 at 16:56 +, Peter Clifton wrote:
> PS.. I found what was causing your assert failure. The gory details were
> only sent to geda-dev, but I can copy you if you want.
Great!
I can read it in the archives with my web-browser.
I noticed some days ago that geda-dev is active ag
*If* you have usenet access:
sci.electronics.basic
sci.electronics.design
There's also:
Electronics_101 at Yahoo! Groups
But traditionally the "regulars" here (geda-user) occasionally ask
design questions, as well as on #geda. Nobody seems to mind as long
as it doesn't get out of hand.
On Tue, 2009-11-10 at 10:17 +0100, Stephan Boettcher wrote:
> Peter Clifton writes:
>
> >> Thank you for coding!
> >
> > Thanks for the feedback - it is the fact that I know others are using
> > the code which keeps me improving it beyond what I needed last time I
> > was designing PCBs.
>
> Cur
On Tue, 2009-11-10 at 17:26 +0100, Stefan Salewski wrote:
> I wonder if there is a better place to ask simple electronics questions
> like OpAmp behaviour?
>
> I think newsgroup sci.electronics.design is not too bad?
>
> For this list we already have much traffic -- user questions and some
> deve
I wonder if there is a better place to ask simple electronics questions
like OpAmp behaviour?
I think newsgroup sci.electronics.design is not too bad?
For this list we already have much traffic -- user questions and some
developer discussion. My personal view is, that it is fine to see the
talk a
On Tue, Nov 10, 2009 at 06:08:41AM -0500, gene glick wrote:
> SR definition is SR = 2 * pi * f * Vpk
Nope. That's the maximum *signal* rate of change for a sinewave. I
think you know that, but since there seems to be a lot of vague
misunderstanding about slew rate in this thread...
> So I need
For the opa2132, it's not clear what the slew rate would do as it
comes out of saturation but it may well only really add some delay
rather than reduce the slew rate.
Using opamps as comparators can be tricky. Alan's suggestion of using
something from the LM339 / LM2907 / LM3302 comparator family
The gain is set at -10. The prior stage has gain, and off-hand I don't
recall how large the signal is, I'll check.
GBW for the part is 8MHz, I run it at 5kHz*10= 50 kHz GBW - plenty of
headroom there.
SR definition is SR = 2 * pi * f * Vpk
So I need SR > 6.28 * 5000 cycles/sec * 15 Volts, or 4
Hi Gene,
Some more things to think about as sanity checks.
Following on from Peter's question, what is the gain of your amplifier
(including any effects of the source resistance if it's an inverting
amplifier configuration)?
You say that "The gain is sufficiently large that the opamp is driven
i
Peter Clifton writes:
>> Thank you for coding!
>
> Thanks for the feedback - it is the fact that I know others are using
> the code which keeps me improving it beyond what I needed last time I
> was designing PCBs.
Currently I do not do any layout work, but I'd like to try the new GL
and 3D work
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