Path: ...!weretis.net!feeder8.news.weretis.net!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail
From: Bill Sloman <bill.sloman@ieee.org>
Newsgroups: sci.electronics.design
Subject: Re: A collection of monographs on high accuracy electronics
Date: Wed, 12 Jun 2024 15:00:27 +1000
Organization: A noiseless patient Spider
Lines: 103
Message-ID: <v4ba1h$1gde1$1@dont-email.me>
References: <33c76j1cr78uhuk3djabivck4gbpe4dq9i@4ax.com>
 <v44n6p$3l18b$1@news.eternal-september.org> <v44qqi$3lquc$3@dont-email.me>
 <v44r4j$3mhiv$1@dont-email.me> <f9fc6j9c24haru81rkduufhjur42vbr53f@4ax.com>
 <v45hct$3tldi$1@dont-email.me> <6djc6jhurdaoqkvgnp0rcb1f4tci4da5pm@4ax.com>
 <c54cea67-c288-c6f7-e1fc-edade2f4b5e5@electrooptical.net>
 <5a46f302-382b-12de-f41d-61335179fe63@electrooptical.net>
 <l7th6jdahpsfe0cbd7bvi74advehliqcdo@4ax.com>
 <1j0i6j9uoo7c0b59btpopsapf1q29t61q5@4ax.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 8bit
Injection-Date: Wed, 12 Jun 2024 07:00:34 +0200 (CEST)
Injection-Info: dont-email.me; posting-host="1236ab842aa8558cc41d140afb35f582";
	logging-data="1586625"; mail-complaints-to="abuse@eternal-september.org";	posting-account="U2FsdGVkX19Yw6WYoAS8+NXmcWpBZjUiPL68Q8Qg7TI="
User-Agent: Mozilla Thunderbird
Cancel-Lock: sha1:DZ2Yp99x0M3F7i0N5dGUfHIyoRA=
X-Antivirus-Status: Clean
In-Reply-To: <1j0i6j9uoo7c0b59btpopsapf1q29t61q5@4ax.com>
X-Antivirus: Norton (VPS 240611-2, 11/6/2024), Outbound message
Content-Language: en-US
Bytes: 5184

On 12/06/2024 12:11 pm, john larkin wrote:
> On Wed, 12 Jun 2024 02:50:19 +0100, JM <sunaecoNoSpam@gmail.com>
> wrote:
> 
>> On Mon, 10 Jun 2024 15:14:40 -0400, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:
>>
>>> On 2024-06-09 21:43, Phil Hobbs wrote:
>>>> On 2024-06-09 20:55, JM wrote:
>>>>> On Mon, 10 Jun 2024 00:29:17 -0000 (UTC), Phil Hobbs
>>>>> <pcdhSpamMeSenseless@electrooptical.net> wrote:
>>>>>
>>>>>> JM <sunaecoNoSpam@gmail.com> wrote:
>>>>>>> On Sun, 9 Jun 2024 18:09:24 -0000 (UTC), Phil Hobbs
>>>>>>> <pcdhSpamMeSenseless@electrooptical.net> wrote:
>>>>>>>
>>>>>>>> Jeroen Belleman <jeroen@nospam.please> wrote:
>>>>>>>>> On 6/9/24 19:02, ehsjr wrote:
>>>>>>>>>> On 6/7/2024 9:14 PM, JM wrote:
>>>>>>>>>>> A collection of monographs on high accuracy electronics written
>>>>>>>>>>> by Mr.
>>>>>>>>>>> Chris Daykin, following his career predominantly in metrology.
>>>>>>>>>>>
>>>>>>>>>>> Unfortunately Chris will be unable to complete the unfinished
>>>>>>>>>>> monographs (having started end of life care) but there is plenty of
>>>>>>>>>>> interest to any analogue engineer.
>>>>>>>>>>>
>>>>>>>>>>> https://1drv.ms/b/c/1af24d72a509cd48/EZhO_rP5-glDmxtc4ZHycvYBhrsqmyC5tuZjt2NFFsS0gQ?e=Wq2Yj0
>>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> Thanks!
>>>>>>>>>> Ed
>>>>>>>>>
>>>>>>>>> I have an issue with his definition of resistor noise power
>>>>>>>>> as the product of open-circuit noise voltage and short-circuit
>>>>>>>>> current. That makes no sense.
>>>>>>>>>
>>>>>>>>> There's more than that, probably, but that just jumped out at
>>>>>>>>> me.
>>>>>>>>>
>>>>>>>>> Jeroen Belleman
>>>>>>>>>
>>>>>>>>
>>>>>>>> It?s four times too high, for a start.
>>>>>>>>
>>>>>>>> Cheers
>>>>>>>>
>>>>>>>> Phil Hobbs
>>>>>>>
>>>>>>> "It is shown elsewhere [1] that the noise power is four times the heat
>>>>>>> energy which would flow down the conductors
>>>>>>> from a warm source resistor to a matching cold resistor."
>>>>>>>
>>>>>>
>>>>>> Which, if true, would solve all our energy problems, except that
>>>>>> thermodynamic systems would all be unstable.
>>>>>>
>>>>>> The thermal noise power produced by a resistor into a matched load is kT
>>>>>> per hertz.
>>>>
>>>>>
>>>>> Sure, which is what he states.  By mentioning a hot and cold resistor
>>>>> he makes it clear that net energy flow is from hot to cold, and that
>>>>> the T refers to the hot source.
>>>>>
>>>> But apparently he says that it's four times larger than that.
>>>>
>>>> I'm not making a microsoft account just to download the PDF, so if you
>>>> want to discuss it further, you could email it to me.
>>>>
>>>> Cheers
>>>>
>>>> Phil Hobbs
>>>>
>>>>
>>>>
>>> Bill was kind enough to send me a copy (thanks again, Bill), and right
>>> there on P. 374, the author says,
>>>
>>> Pn = 4kTB
>>>
>>> which is a factor of four too high.
>>>
>>
>> No it isn't. He is calculating the thermal noise power dissipated in an unloaded resistor - something (or at least the related noise voltage) which is actually required in the design process of a transducer/amplifier low S/N system.
> 
> What does that mean? Do unconnected resistors get hot?

No. They certainly don't get warmer than their enviroment, though they 
do interact with it.

> A box of resistors could start a fire!

Obviously not. John Larkin's sense of humour is depressingly pathetic.

-- 
Bill Sloman, Sydney



-- 
This email has been checked for viruses by Norton antivirus software.
www.norton.com