From: Paul Burridge
Subject: Re: Transistor amplifiers v. frequency in SPICE
References: <firstname.lastname@example.org> <email@example.com> <firstname.lastname@example.org> <3E274701.2D0D@sneakemail.com>
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Date: Fri, 17 Jan 2003 07:44:20 +0000
NNTP-Posting-Date: Fri, 17 Jan 2003 10:41:55 GMT
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On Thu, 16 Jan 2003 18:57:53 -0500, Mike Monett
>Are you still having trouble getting AC Analysis running? Time to switch.
I don't think the case is fully made out yet, Mike. I still think it's
*my* fault rather than the s/ware. For instance, another circuit I
constructed in SPICE is a class C RF amp with a L/C tank in the
collector load. When I run the AC sweep for *this* circuit, I get
precisely the kind of output trace I'd expect to see in real life:
basically zilcho until the sweep approaches resonance, then the
classic hi-Q peak of 100v at precisely 3.57Mhz (the tank's Fres) then
rapidly falling back to zilcho again as the sweep continues ever
upward in frequency. Under these circumstances, I can't see how it can
be anything other than operator error with the other circuit
(previously posted here first using a BC337 then a 2N2222a in case
anyone wishes to try it for themselves).
>To answer your question, you should be able to step the value through
>whatever range you wish and have multiple ovelaid plots showing the
>results. Then, you should be able to identify the min, max, delta, etc.
>for each plot with the cursor keys. You should also be able to generate
>3D plots from data.
It can - subject to being set up correctly - perform the above. Not
sure about the last one though: what do you mean by 3D plots?
>If your software does not allow you to do this, take a look at Microcap.
>It had these features since 1988, and probably has improved them by now.
Well, I did actually download the demo version of MC last night. But
it requires PKunzip to unzip it. I have a copy of this utility on
floppy, but guess what? My floppy drive's kaput. :-(
"What is now proved was once only imagin'd"
- William Blake, 1793