Warning: mysqli::__construct(): (HY000/1203): User howardkn already has more than 'max_user_connections' active connections in D:\Inetpub\vhosts\howardknight.net\al.howardknight.net\includes\artfuncs.php on line 21
Failed to connect to MySQL: (1203) User howardkn already has more than 'max_user_connections' active connectionsPath: ...!feed.opticnetworks.net!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail
From: legg
Newsgroups: sci.electronics.design
Subject: Re: fast NPN in LT Spice
Date: Mon, 10 Jun 2024 17:27:59 -0400
Organization: A noiseless patient Spider
Lines: 60
Message-ID:
References: <4n2q5jln0sb9oqbfp81jm723tbjf7tol80@4ax.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
Injection-Date: Mon, 10 Jun 2024 23:26:07 +0200 (CEST)
Injection-Info: dont-email.me; posting-host="9601cbb5c79b45170877248f59b32bbd";
logging-data="683077"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1/K/7BP/8rpGJjB3EZIjRHB"
Cancel-Lock: sha1:admM8rEARuFzL7Sthho4VrjVLb0=
X-Newsreader: Forte Agent 4.2/32.1118
Bytes: 3585
On Sat, 8 Jun 2024 03:29:11 +1000, Bill Sloman
wrote:
>On 7/06/2024 11:24 pm, legg wrote:
>> On Fri, 7 Jun 2024 14:03:16 +1000, Bill Sloman
>> wrote:
>>
>>> On 7/06/2024 4:05 am, legg wrote:
>>>> On Thu, 6 Jun 2024 23:18:12 +1000, Bill Sloman
>>>> wrote:
>>>>
>>>>> On 6/06/2024 1:46 pm, legg wrote:
>
>
>
>> That's sort of what I'm talking about. You choose a part, you choose a
>> model, you choose a parameter that allows a model to simulate
>> performance more accurately. You choose a circuit configuration
>> with component values.
>
>You mostly can't chose an EBIC model because the manufacturers treat
>them as "commercial in confidence".
>
>Gummel-Poon isn't as good, but it's mostly adequate.
>
>> From the larger spreadsheet, you see models for 'similar devices
>> varying widely in performance in a particular circuit configuration.
>>
>> So what is it, in the model, or in the circuit configuration, that
>> allows such a wide variation in performance. What parameter is a
>> true predictor? What weakness in the circuit is the wild card?
>
>Silly question. Gummel-Poon doesn't model inverted bipolar transistor
>operation particularly well, but if you want anything else you will have
>measure the device parameters for yourself, and nobody here has ever
>claimed to have done that.
>
>> Looking for understanding or beneficial increase in knowledge here.
>> Not pushing or pulling the benefits or disadvantages of modeling
>> or breadboarding - already have pretty fixed opinions about that.
>
>Do try to understand what practical circuit designers actually do.
>
>I've never seen anybody set up a "spreadsheet" of transistor models.
>
>The process is mostly working out what you can do with what you can get.
>
>The models aren't perfect, and individual devices aren't identical, so
>coping with production variation is part of the job. Some parts are
>sorted by the manufacturer after production, which gives you
>funny-looking parameter distributions.
>
>--
>Bill Sloman, Sydney
Right, I see Q2 normally inverted.
C2 seems unneccessarily loaded.
RL