From: Terry Pinnell
Subject: Re: Transistor amplifiers v. frequency in SPICE
Date: Thu, 16 Jan 2003 20:32:36 +0000
References: <email@example.com> <firstname.lastname@example.org>
NNTP-Posting-Date: Thu, 16 Jan 2003 20:33:06 +0000 (UTC)
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email@example.com (Terry) wrote:
>firstname.lastname@example.org (Paul Burridge) wrote in message news:<email@example.com>...
>> Winfield Hill wrote in message news:...
>> > Yep, down by 8dB at 500kHz, pretty close to the above estimate.
>> > That's entirely a collector-capacitance effect.
>> > . +24V
>> > . |
>> > . 150k
>> > . +24V | 1nF
>> > . | +----||--- out
>> > . 150k |
>> > . 1nF | C BC337
>> > . --||--+---B 2n2222
>> > . | E
>> > . 150k |
>> > . | +-----,
>> > . gnd | |
>> > . 140k 1nF
>> > . | |
>> > . gnd gnd
>> > Another problem with your circuit (did I get it right?),
>> Yes, except I'm using 10v+ supply rail.
>I've only just got round to simulating your circuit, Paul, but reckon
>the gain is only 19 at 1 kHz (with my arbitrary assumption of 1M
>load). It's virtually unchanged with 24 V or 10 V supply.
...but I suspect that's because you're now using 100 nF caps. I
interpreted your reply to Win as confirming his schematic was correct,
but I've since found your earlier ASCII with 100 nF. If so, it
simulates a gain of 177, squaring with your hand calculation.
Hobbyist, West Sussex, UK