Re: A collection of monographs on high accuracy electronics

On Tue, 18 Jun 2024 23:32:40 -0000 (UTC), Phil Hobbs wrote:

JM <sunaecoNoSpam@gmail.com> wrote:

On Mon, 17 Jun 2024 07:09:12 -0700, john larkin <jl@650pot.com> wrote:
 

On Sun, 16 Jun 2024 22:20:43 +0100, JM <sunaecoNoSpam@gmail.com>
wrote:
 

On Tue, 11 Jun 2024 19:11:51 -0700, john larkin <jl@650pot.com>
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.ÿ 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?
 
A box of resistors could start a fire!

 
And why would that occur.  In thermal equilibrium there is no net
transfer of energy either from or to the resistor (when averaged over
any time interval of interest appropriate to the bandwidth of current
electronic circuits).
 
The so called resistor thermal "available noise power" KTB implies
there is a net power delivery from a source to a load.  In the case
of maximum transfer the source must dissipate within itself exactly
the same as it delivers to the load (due to having the same
resistance). However if the so called load is at the same temperature
as the source it also delivers KTB to the source and dissipates KTB
within its own resistance.  Thus there is no net transfer of energy
between the two resistors in thermal equilibrium.  If one is at a
lower temperature than the other there will be a net transfer of
energy, but this will be completely dwarfed in any practical system
by the energy transferred due to thermal conductivity between the two
resistors.
 
So the power dissipated in a system of two equal value resistors is
4KTB.  But this also holds if the two resistors have different
values, including the situation where one of the resistors is a short
or open circuit (i.e. leaving a single open or short circuit
resistor).  So it is entirely reasonable to state (as many engineers
do) that the thermal noise power of a resistor is 4kTB.

 
If as stated "the thermal noise power dissipated in an unloaded
resistor" is nonzero, a reel of 0805s is a fire hazard. What would

 
No taxation without representation No chilli without beans No
fluctuation without dissipation
 
Which one is true?

 
No motion without perpetual, apparently. ;)

No trolls without Australia.
Actually, I thought your idea of correcting the document had much merit,
Phil. You and the other big shots here can get down to the task. I'll make
the tea and correct the spelling. :-)