Reply-To: "Kevin Aylward"
From: "Kevin Aylward"
References: <firstname.lastname@example.org> <email@example.com> <firstname.lastname@example.org> <email@example.com> <12j4LzC+fEp9EwgG@jmwa.demon.co.uk> <firstname.lastname@example.org>
Subject: Re: Problems with Electronics Workbench - timestep errors
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Date: Wed, 9 Oct 2002 22:20:51 +0100
NNTP-Posting-Date: Wed, 09 Oct 2002 22:32:01 BST
"Roger Johansson" wrote in message
> "Kevin Aylward" wrote:
> >It don't seem like you have the generater setup correctly, or the run
> >The "Sine" generator has three sets of text fields.
> >1 AC spec. This should usually be set to 1 Volt so that output=gain.
> >This is *only* used in AC runs. i.e. v against f
> >2 DC spec. This is *only* used in DC runs. v against v
> >3 Time domain spec. These are the fields for peak voltage, frequency
> >offset. This is only used for TRANS runs. V against time
> >Flat AC graphs usually mean V AC is set to OV.!
> >You use the blue "SS" to set up the runs i.e. AC sweep, transient
> >So, you need to make sure that both the generator *and* requested run
> >are in agreement. This is true of *any* spice. You must know what it
> >you want to actually do!
> In EWB we only need to know that we want to take a look at the
> waveform on a certain wire, and use the oscilloscope as in reality.
Ho hum. That's all you do in SS. However, as I noted, you *must* know
what it is you are doing. Are you doing a frequency response or a time
> We do not understand much of all the terms and settings you talk about
> above, and there is no need to know.
Yes you do, if you expect to do real electronics.
To understand electronics *at all* you *must* learn what these terms
mean. These particular terms are *so* basic, that if you don't want to
learn them, you should give up electronics. I mean it. Its that simple.
Why? see below.
> I saw that Jim created a signal generator for spice some time ago.
> That is probably very useful.
> In EWB there is already a signal generator, or rather a function
> generator. It is already set to default values, sinus, 1kHz, 1Volt.
> So it is easy to change to what you want, but even if you do not
> understand how to set it the default settings will give a signal.
> That is a user friendly spice.
Jesus wept dude. I agree, that things need to be simple. However, they
can not be so simple that you don't know what you are doing at all.
Look, I can give ABC instructions for you to build an oscillator,
however, building it would mean nothing. It would not show that you
understood *anything* at all about electronics.
Regarding the above terms.
1 If you want to do a frequency response of a circuit, you *must*
*know/learn/understand* that you need to generate an *AC* signal and do
a frequency response plot of AC signal output verses frequency. You need
to know how to set-up generators to do this. For example, what if you
want top look at power supply rejection as well etc...You need to know
what an AC response actually means.
2 If you want to look at a signal in the time domain, you *must*
*understand* that you apply , for example, a Sine wave, square wave, or
triangle wave and specify it by parameters related to what it looks like
in time. You need to know what an Transient response actually means.
Sure, you can connect up signal generators and scopes and see all the
little bitty pretty pictures, if that makes you happy, but you wont be
SuperSpice, a very affordable Mixed-Mode
Windows Simulator with Schematic Capture,
Waveform Display, FFT's and Filter Design.