From: Paul Burridge
Subject: Re: Transistor amplifiers v. frequency in SPICE
References: <email@example.com> <firstname.lastname@example.org> <email@example.com> <firstname.lastname@example.org>
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Date: Tue, 21 Jan 2003 07:33:24 +0000
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On 20 Jan 2003 15:19:38 -0800, email@example.com (Paul Burridge)
>Terry Pinnell wrote in message
>> A Spice AC Analysis is a 'small signal analysis', but no particular
>> value of source signal is used. In that respect, it's independent of
>> the Transient Analysis. All that's required is that at least one
>> independent source is specified with an ACc value.
>Thanks for the reply, Terry. Apologies for the delay in responding,
>but once again I had to go via Google to be able to see it. :-(
>I'll have a good look over it and hopefully reply in full 2morrow.
Okay, back again, despite the barrier of computer technology. :-(
I've been unable to quote your post this time since it - along with
God knows how many others - has failed to appear on my news server.
I'll therefore have to address your points in a necessarily buggered
Firstly, you say (in relation to AC analysis): "All that's required is
that at least one independent source is specified with an AC value"
The question arises as to which parameter that value should relate?
(amplitude, frequency, phase, whatever)
Secondly, I'm aware the load is "crucially important" but I think
you've taken my remark out of context with the original point. I'm
trying to get a better understanding of SPICE here within this thread,
not trying to solve any real-world problem. All I need to know is that
whatever the load resistance is, we are both modeling for the *same*
value of it! At this stage, I'm simply trying to get my simulations to
agree with yours; that's all.
You give six different values of load and gain figures for each, for
which I'm very grateful. Can you confirm that the component values you
are using in this sim. are the same as those appearing on your web
site in the schematic entitled (something like) "PaulAmp"?
To answer your last question, B2 Spice is the applicable s/ware, as
listed on your site so I assume you're familiar with it.
"What is now proved was once only imagin'd"
- William Blake, 1793