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 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: References: <33c76j1cr78uhuk3djabivck4gbpe4dq9i@4ax.com> <6djc6jhurdaoqkvgnp0rcb1f4tci4da5pm@4ax.com> <5a46f302-382b-12de-f41d-61335179fe63@electrooptical.net> <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 > wrote: > >> On Mon, 10 Jun 2024 15:14:40 -0400, Phil Hobbs 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 >>>>> wrote: >>>>> >>>>>> JM wrote: >>>>>>> On Sun, 9 Jun 2024 18:09:24 -0000 (UTC), Phil Hobbs >>>>>>> wrote: >>>>>>> >>>>>>>> Jeroen Belleman 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