Gary,
i did not reply to your post but to Georgs "least cost calculator".
I myself use simulation tools for several years and would grade them
essential.
The protel simulation tool should be improved in its user interface
(displaying and documentation of the simulation results ...) primarily. No
new fancy gimmicks please, keep it simple (no "least cost calculator").

Rolf Molitor
Ing.Buero i2e
Remscheid / Germany

-----Ursprüngliche Nachricht-----
Von: "Gary Packman" <[EMAIL PROTECTED]>
An: "Protel EDA Forum" <[EMAIL PROTECTED]>
Gesendet: Dienstag, 2. Juli 2002 10:50
Betreff: Re: [PEDA] AW: SPICE sim question


> Rolf,
> I am not sure of what part of my post you thought was a joke, it was a
> rather lengthy reply, but I assure you I was not joking about anything.
> Simulation has to do with the design of robust, reliable, stable
> circuits at the lowest possible cost. It is not just an R&D toy.  Anyone
> who believes they can sit down and design a circuit in one try that
> lives up to the above goals is kidding themselves.  If you ask ten
> designers to build a heart rate monitor, you will get ten different
> products.  One of them will be better and quite possibly less expensive
> than the others.  Simulation helps zero in and optimize every one of
> these targets.
>
> Gary Packman
>
>
>
> Rolf Molitor wrote:
> >
> > That has nothing to do with circuit simulation.
> > You were just joking, right ?
> >
> > Rolf Molitor
> > Ing.Buero i2e
> > Remscheid / Germany
> >
> > -----Urspr ngliche Nachricht-----
> > Von: "Georg Beckmann" <[EMAIL PROTECTED]>
> > An: "'Protel EDA Forum'" <[EMAIL PROTECTED]>
> > Gesendet: Samstag, 29. Juni 2002 14:25
> > Betreff: [PEDA] AW: SPICE sim question
> >
> > > Hi Gary,
> > >
> > > I want to use the simulator for a Monte carlo analyse for the
following
> > > question.
> > > To simplify what I mean is, imagine a bridge circuit with four
resistors
> > of
> > > 1% tolerance.
> > > The circuit is usable, if the bridge - voltage is below a certain
limit.
> > How
> > > many
> > > percent of my circuits are usable so that I can decide what's cheaper,
to
> > > throw away
> > > the bad samples or use of more expensive resistors.
> > >
> > > Do you know how this is done ?
> > > When I looked at the examples, they only calculated the worst case of
a
> > > circuit, but
> > > that's not the question, I want to get the distribution of a
parameter.
> > >
> > > Georg
> > >
> > >
> > > Afshin Salehi wrote:
> > > >
> > > > Just out of curiosity, what types of things do you guys run
simulations
> > > on?
> > >
> > > Amplifiers, linear and switching power supplies, filters, and just
about
> > > anything else that will need tweaking on the bench.
> > >
> > > > What drives you to run a simulation on that specific device?
> > >
> > > Testing for stability, what range of component values (tolerance) will
> > > work reliably, gain, rolloff, keeping signal levels away from the
rails
> > > when designing high gain multi-stage amplifiers, and most important of
> > > all, gaining rapid insight into what happens when you go outside the
> > > box.  Also, nothing catches fire or explodes in a simulator!
> > >
> > > >How accurate is the simulation to a real world bread boarded device?
> > > >
> > > Once you learn how to use simulation I would say about 98% accurate,
but
> > > there is a giant proviso here, you must have accurate models and you
> > > must understand the limitations of the simulation process.  I cannot
> > > remember the last time a finished product did not behave as the
> > > simulation did.  The more often you simulate, the better you and your
> > > results get.
> > >
> > > > Jon Elson said it takes a day at first then maybe an hour or so each
> > time
> > > to
> > > > remember things, how is that justified to your boss?  I am really
just
> > > > curious as to what things people run sims on, how complex those
circuits
> > > > that are simulated are, and if the tests are worth while?
> > > >
> > > I use an old but very capable DOS version ($15,000 when new) of
PSPICE.
> > > I can hand type an ASCII circuit description page in about a half-hour
> > > (three or four op-amps and twenty or thirty passive parts).  Another
> > > twenty minutes to patch typos and missed connections. After the
circuit
> > > is running you can do a number of tests in minutes that would take a
> > > week on the bench.  Whether it is worth the trouble or not all depends
> > > on what you're doing.  The last thing I did was a strain gauge
amplifier
> > > (something I never did before).  Had the circuit up and running in one
> > > afternoon, cost of components about $10 versus a packaged product with
> > > similar specs from Omega for $400.  Is that worthwhile?  My boss
thought
> > > so.
> > >
> > > It all depends...
> > > Gary Packman
> > >
> > > > Thanks,
> > > >
> > > > Afshin
> > > >
> > > >
************************************************************************
> > > > * Tracking #: 089C581B73790B40A34A5F9530FFA0A756B58F96
> > > > *
> > > >
************************************************************************

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