Re: Cal Lab Magazine - International Journal of Metrology
Incidentally, this functionality has been available on x86 PCs for decades, and was prominently displayed inside the back cover of the WordPerfect 5.1 manual (circa 1990). I haven't looked lately (no WP manual) and didn't look back then, but I think it directly called the decimal ASCII value for the character, including the double-byte characters. You needed a keyboard with a 10-key number pad, which means that most of today's laptops are crippled. I was the only person I knew who liked WordPerfect, primarily because of this feature. I became a disgruntled former user when the WP publisher released WP 5.2, buried this functionality, and slapped a GUI on top of the app that slowed it down to 1/5 its previous speed. 73 Jim N6OTQ On Thu, Sep 1, 2022 at 4:34 AM Kenneth Greenough via groups.io <g8beqglossop@...> wrote:
On just about any PC keyboard you can type a ? by holding down <Alt>, typing 2 3 0 on the numeric keypad, and releasing <Alt>. In some applications NumLock must be on for this to work. I have a table of the numbers for common electrical symbols taped on the edge of my monitor, so I can type things like Ω or √-1 8 Σ π.
Steve Hendrix
Thank you Steve, Something I never knew before, now I'll have to spend a few hours exploring.
regards ken G8BEQ
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How do you vary the size of the quantum hole?
Ken g8beq
On 01/09/2022 12:11, Jeff Green wrote:
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In a prior life I was a chemical
engineer....
?
This is getting pretty theoretical.
Quantum Dot "Solar Cells" can be tuned
for different wavelengths by varying the size of the quantum
"hole,"
AKA "Quantum Well."
?
?
?
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Re: Cal Lab Magazine - International Journal of Metrology
On Wed, 31 Aug 2022 at 15:10, Eric <ericsp@...> wrote: I was also corrected once on the time base side of things: ? ns = nano second ? nS = nano siemens ? apparently, some areas this is the unit of interest and is taken quite seriously.
Yup, e.g. mS is part the specification of every FET, where it plays the same role as Hfe in BJTs. (Hfe is, of course, playing fast and loose with capitalisation!)
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Re: Cal Lab Magazine - International Journal of Metrology
On just about any PC keyboard you can type a ? by holding down
<Alt>, typing 2 3 0 on the numeric keypad, and releasing
<Alt>. In some applications NumLock must be on for this to
work. I have a table of the numbers for common electrical
symbols taped on the edge of my monitor, so I can type things
like Ω or √-1 8 Σ π.
Steve Hendrix
Thank you Steve, Something I never knew before, now I'll have to
spend a few hours exploring.
regards ken G8BEQ
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Re: Cal Lab Magazine - International Journal of Metrology
I just took a look at a few hobbyist magazines and some product schematics from several different decades, and your speculation looks pretty solid. Based on that random, statistically insignifcant sample, the UK has been quite consistent over time and across publications aimed at quite different readers. The US, not so much, even within a single company. The earliest schematic for HP's first product, the 200A, surprised me with its use of the mu symbol. A schematic for the same product, but of later manufacture, uses "m" for micro. a seemingly backwards step. Textbooks and refereed journals paid the extra ha'penny for a mu, but hobby magazines were a different story.
I did not check any German or French pubs to see what conventions were followed there.
-- Cheers,
Tom
--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
350 Jane Stanford Way
Stanford University
Stanford, CA 94305-4070
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On 9/1/2022 01:56, G8HUL wrote: Very likely a UK/US thing. pF (puff) has always been in common usage here from the very early days so mmF would not have been common; nano, however, took some time to gain traction, probably as late as the 1970s. We would have asked for a thousand puff capacitor rather than 1n. It seemed to have been pushed by the capacitor manufacturers and their markings, probably to save space.
73
Jeff G8HUL
-----Original Message-----
From: [email protected] <[email protected]> On Behalf Of Tom Lee
Sent: 01 September 2022 09:42
To: [email protected]
Subject: Re: [Test Equipment Design & Construction] Cal Lab Magazine - International Journal of Metrology
Hi, Jeff,
It is quite probably an example of differing usage in the US v the UK, with the US simply not willing to pay for a mu until recently. :)? And "mickey-mikes" certainly sounds American, given its probable Disney-inspired etymology, so it doesn't surprise me that you've never heard it. "Two peoples, divided by a common language" ... (a great line, even if Shaw apparetnly didn't actually say it).
-- Cheers,
Tom
--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
350 Jane Stanford Way
Stanford University
Stanford, CA 94305-4070
On 9/1/2022 01:08, G8HUL wrote:
Not so much a mistake as merely a holdover from the days when mF was
in fact the conventional abbreviation for microfarad,
I have handbooks dating back to 1925 and they use ? as the abbreviation for 10-3, but some still prefer Jars for capacitance! I is possible that it is a US v UK thing, or just widespread incorrect usage.
Never heard any reference to the expression "mickey-mike".
73
Jeff G8HUL
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Re: Cal Lab Magazine - International Journal of Metrology
Very likely a UK/US thing. pF (puff) has always been in common usage here from the very early days so mmF would not have been common; nano, however, took some time to gain traction, probably as late as the 1970s. We would have asked for a thousand puff capacitor rather than 1n. It seemed to have been pushed by the capacitor manufacturers and their markings, probably to save space.
73
Jeff G8HUL
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-----Original Message----- From: [email protected] < [email protected]> On Behalf Of Tom Lee Sent: 01 September 2022 09:42 To: [email protected]Subject: Re: [Test Equipment Design & Construction] Cal Lab Magazine - International Journal of Metrology Hi, Jeff, It is quite probably an example of differing usage in the US v the UK, with the US simply not willing to pay for a mu until recently. :)? And "mickey-mikes" certainly sounds American, given its probable Disney-inspired etymology, so it doesn't surprise me that you've never heard it. "Two peoples, divided by a common language" ... (a great line, even if Shaw apparetnly didn't actually say it). -- Cheers, Tom -- Prof. Thomas H. Lee Allen Ctr., Rm. 205 350 Jane Stanford Way Stanford University Stanford, CA 94305-4070 On 9/1/2022 01:08, G8HUL wrote: Not so much a mistake as merely a holdover from the days when mF was
in fact the conventional abbreviation for microfarad,
I have handbooks dating back to 1925 and they use ? as the abbreviation for 10-3, but some still prefer Jars for capacitance! I is possible that it is a US v UK thing, or just widespread incorrect usage.
Never heard any reference to the expression "mickey-mike".
73
Jeff G8HUL
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Re: Cal Lab Magazine - International Journal of Metrology
Hi, Jeff,
It is quite probably an example of differing usage in the US v the UK, with the US simply not willing to pay for a mu until recently. :)? And "mickey-mikes" certainly sounds American, given its probable Disney-inspired etymology, so it doesn't surprise me that you've never heard it. "Two peoples, divided by a common language" ... (a great line, even if Shaw apparetnly didn't actually say it).
-- Cheers,
Tom
--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
350 Jane Stanford Way
Stanford University
Stanford, CA 94305-4070
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On 9/1/2022 01:08, G8HUL wrote: Not so much a mistake as merely a holdover from the days when mF was in fact the conventional abbreviation for microfarad,
I have handbooks dating back to 1925 and they use ? as the abbreviation for 10-3, but some still prefer Jars for capacitance! I is possible that it is a US v UK thing, or just widespread incorrect usage.
Never heard any reference to the expression "mickey-mike".
73
Jeff G8HUL
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Re: Cal Lab Magazine - International Journal of Metrology
Now instead of micky-mikes,we would ask for a 270 puff cap.
John
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On 9/1/2022 1:08 AM, G8HUL wrote: Not so much a mistake as merely a holdover from the days when mF was in fact the conventional abbreviation for microfarad,
I have handbooks dating back to 1925 and they use ? as the abbreviation for 10-3, but some still prefer Jars for capacitance! I is possible that it is a US v UK thing, or just widespread incorrect usage.
Never heard any reference to the expression "mickey-mike".
73
Jeff G8HUL
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Re: Cal Lab Magazine - International Journal of Metrology
Not so much a mistake as merely a holdover from the days when mF was in fact the conventional abbreviation for microfarad,
I have handbooks dating back to 1925 and they use ? as the abbreviation for 10-3, but some still prefer Jars for capacitance! I is possible that it is a US v UK thing, or just widespread incorrect usage. Never heard any reference to the expression "mickey-mike". 73 Jeff G8HUL
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Re: Cal Lab Magazine - International Journal of Metrology
You'd not say "a 2 watts light bulb" though,
would you?
Of course not, which is why my example, the entirety of which is
delimited with quote marks, does not contain an adjectival clause.
You seem to have lost track of the topic of discussion, which was
the claim that there was language in an official document
proscribing the use of pluralizations of units. No such
documentation has been found. Now you seem to think that I was
asserting that one must always pluralize units or
some such thing. I've made no such assertion, but if you want to
continue along those lines, I recommend a visit to the Argument
Clinic.
--Cheers,
Tom
--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
350 Jane Stanford Way
Stanford University
Stanford, CA 94305-4070
On 8/31/2022 22:07, Orin Eman wrote:
On Wed, Aug 31, 2022 at 11:56 AM Tom Lee < tomlee@...>
wrote:
I disagree, more strongly now than before,
given the citation that you present in bold. The key word
that you have missed is “symbol”. One certainly should not
add an “s” to pluralize a symbol. But the unit’s name is
not a symbol. The symbol for watt is W, but the unit’s
name is watt.
This was the point I’ve made a couple of times
already. Can we get off the carousel now?
A power of “2 watt” is simply wrong.
When used adjectivally, it seems there is no plural.? But
you'd probably say that light bulb consumes (dissipates?) "2
watts" when supplied with its rated voltage.
I think the standards people are doomed on this one,
especially for plus or minus 1 of whatever which most
English speakers will always want to be singular.
Orin.
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Re: Cal Lab Magazine - International Journal of Metrology
On Wed, Aug 31, 2022 at 11:56 AM Tom Lee < tomlee@...> wrote: I disagree, more strongly now than before, given the citation that you present in bold. The key word that you have missed is “symbol”. One certainly should not add an “s” to pluralize a symbol. But the unit’s name is not a symbol. The symbol for watt is W, but the unit’s name is watt.
This was the point I’ve made a couple of times already. Can we get off the carousel now?
A power of “2 watt” is simply wrong.
You'd not say "a 2 watts light bulb" though, would you?
When used adjectivally, it seems there is no plural.? But you'd probably say that light bulb consumes (dissipates?) "2 watts" when supplied with its rated voltage.
I think the standards people are doomed on this one, especially for plus or minus 1 of whatever which most English speakers will always want to be singular.
Orin.
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I have been wondering if it’s possible to make an RF ammeter from nichrome wire and measure the IR radiation to measure the heat caused by the RF current. A DC substitution would allow the RF current to be determined. Similar to what HP & Boonton did, but not using a thermocouple. There are a few possible techniques for measuring the temperature without actually being in contact with the nichrome wire
1) Thermopile which I believe are used in cheap (<$20 USD) IR thermometers?
2) Photodiode.? The issue here is that the peak emission of a hot wire at 100 deg C is 7.8 um, which is much longer than any photodiode technology I am aware of, but there will still be emissions at shorter wavelengths.?
Silicon has the advantage of being very cheap, but the cutoff wavelength is quite short (around 1.1 um). Germanium is less readily available, but works to longer wavelengths??The dark current is higher too. InGaAs devices work to around 2.6 um. These are usually cooled, and are unlikely to be cheap.?
3) CCD, as used in thermal imaging cameras, I believe they are silicon?
Dave?
-- Dr. David Kirkby, Kirkby Microwave Ltd, drkirkby@...Telephone 01621-680100./ +44 1621 680100 Registered in England & Wales, company number 08914892. Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT, United Kingdom
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Re: Cal Lab Magazine - International Journal of Metrology
Not so much a mistake as merely a holdover from the days when mF was in fact the conventional abbreviation for microfarad, just as mmF (micro-microfarad) was used for what we now call the picofarad. Engineers of that era often used the colloquial unit "mickey-mike" (as in, "Hand me that 270 mickey-mike cap"). You'll also come across references to oscilloscopes with "milli-microsecond speed". It took time for the nano- prefix (and its kin) to catch on.
A lot of those older conventions arose in the age of the typewriter, whose limited font choices made it cumbersome to include Greek symbols.
When interpreting component values called out in older documentation, it's important to understand that the conventions of today are, well, the conventions of today. "The past is a different country", as the historians like to point out.
-- Cheers,
Tom
--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
350 Jane Stanford Way
Stanford University
Stanford, CA 94305-4070
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On 8/31/2022 09:42, G8HUL wrote: And as previously stated mF and NF are not the same
I am not sure whether NF (newton farad) is of use to anyone as a unit, but mF (milli farad) is likely to cause confusion as it is often, mistakenly, used for micro farad.
uF is a little more acceptable where a mu is not available in the font.
Regards
Jeff
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The 0-3 Amp meter looks interesting, but I would prefer to find one for $5 at a ham radio swap meet. Or ask a local ham to refer you to an old-timer that used to build their own equipment and might have a well stocked junk box.
Generating 3 amps of RF and running it around to the meter movement doesn't sound appealing. And 1 amp is down at the low resolution end of the scale. Removing the thermocouple and placing it next to the0..02 or whatever ohm resistor and adding an amplifier to make a more reasonable current full scale makes more sense. Be sure to carefully mark the RF terminals and output voltage terminals carefully.
John
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On 8/31/2022 11:23 AM, Jeff Green wrote: I'm not sure if anyone will find these useful, but they might.
Some of these have built in thermocouples to measure RF current. I don't know enough to know what the upper frequency of operation might be.
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Re: Cal Lab Magazine - International Journal of Metrology
On Wed, 31 Aug 2022 at 19:56, Tom Lee < tomlee@...> wrote: I disagree, more strongly now than before, given the citation that you present in bold. The key word that you have missed is “symbol”. One certainly should not add an “s” to pluralize a symbol. But the unit’s name is not a symbol. The symbol for watt is W, but the unit’s name is watt.
This was the point I’ve made a couple of times already. Can we get off the carousel now?
A power of “2 watt” is simply wrong.
Tom
It is odd however how a document from the BIPM
states on page 76 of the PDF
"the luminous efficacy Kcd of monochromatic radiation of frequency 540 × 10^12 Hz is exactly 683 lumen per watt."? I attach another document from the BIPM, this time a screenshot, rather than text, as I can't get symbols to display properly.
However, looking at the NPL website
it would suggest my usage has been incorrect. It has some recommendations, one of which is
For unit values more than 1 or less than -1 the plural of the unit is
used and a singular unit is used for values between 1 and -1.
Dave
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Re: Cal Lab Magazine - International Journal of Metrology
I disagree, more strongly now than before, given the citation that you present in bold. The key word that you have missed is “symbol”. One certainly should not add an “s” to pluralize a symbol. But the unit’s name is not a symbol. The symbol for watt is W, but the unit’s name is watt.
This was the point I’ve made a couple of times already. Can we get off the carousel now?
A power of “2 watt” is simply wrong.
Tom Sent from my iThing; please forgive the typos and brevity
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On Aug 31, 2022, at 06:26, Dr. David Kirkby, Kirkby Microwave Ltd <drkirkby@...> wrote:
? On Wed, 31 Aug 2022 at 01:43, Tom Lee < tomlee@...> wrote:
The rule is that units named for people are not capitalized when
spelled out. That assures that "two watts" is a measure of power,
while "two Watts" refers refers to two family members.
I said earlier that I thought the s should not be there, and cited an BIPM brochure, which did not actually substantiate my statement.? However, this document from the BIPM does.
"A concise summary of the International System of Units, SI"
It gives a logical reason why "2 watt" is correct, and "2 watts" is not.
To quote
"Unit symbols are written using roman (upright) type, regardless of the type used in the surrounding text. They are mathematical entities and not abbreviations; unit symbols are never followed by a full stop (except at the end of a sentence) nor by an ‘s’ for the plural. The use of the correct form for unit symbols is mandatory, and is illustrated by examples in the SI Brochure"
Unfortunately, that SI Brochure is not totally consistent, with both "683 lumen per watt" and "683 lumens per watt" in the same document. Also, multiple references to newtons, but I think the newton is the only unit to suffer from this "error". You will not find any references to farads, amperes,
If the IEEE wants "2 watts", and not "2 watt", then it's their publication, so they can have it. But I don't think it is technically correct. But I am not impressed with the way the IEEE accepts both positive and negative numbers in dB for the return loss of passive components. In one issue of a journal you will see someone write that an antenna had a return loss of -15 dB, and in another article the return loss is quoted as 15 dB. Fortunately the context is usually obvious. Dave
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Re: Cal Lab Magazine - International Journal of Metrology
On 2022-08-31 11:06 AM, Dr. David
Kirkby, Kirkby Microwave Ltd wrote:
My personal opinion is that a lower case u is
perfectly acceptable in emails and other documents where it’s
not easily possible to create a mu, and even if you could,
there’s a good chance someone else might not see it as you
intended.?
On just about any PC keyboard you can type a ? by holding down
<Alt>, typing 2 3 0 on the numeric keypad, and releasing
<Alt>. In some applications NumLock must be on for this to
work. I have a table of the numbers for common electrical symbols
taped on the edge of my monitor, so I can type things like Ω or
√-1 8 Σ π.
Steve Hendrix
|
Re: Cal Lab Magazine - International Journal of Metrology
And as previously stated mF and NF are not the same
I am not sure whether NF (newton farad) is of use to anyone as a unit, but mF (milli farad) is likely to cause confusion as it is often, mistakenly, used for micro farad. uF is a little more acceptable where a mu is not available in the font. Regards Jeff
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Re: Cal Lab Magazine - International Journal of Metrology
(corrected text)???
One of the earliest schematics I crossed was the Howard W Sam's Photofact for a 1951 Westinghouse television.
It used the lower case letter 'u' for? mu, thus a 10 microfarad (microFarad) capacitor was marked? '10 uf'? on the
schematic. Yes it was the lower case? letter 'u' and lower case letter 'f'. Of course there were caps marked 'uuf'
for micromicrofarad, today referred to as picoFarad using the letter pair 'pF'.
It was not until encountering an IBM Selectric typewriter, that the secretaries typing the manuals began using the
actual μ symbol. Before that time, they used the lower case letter 'u' as that was the closest thing on the manual
Underwood typewriters of the period.
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Re: Cal Lab Magazine - International Journal of Metrology
On Wed, Aug 31, 2022 at 10:06 AM Dr. David Kirkby, Kirkby Microwave Ltd <drkirkby@...> wrote: My personal opinion is that a lower case u is perfectly acceptable in emails and other documents where it’s not easily possible to create a mu, and even if you could, there’s a good chance someone else might not see it as you intended. "Might not see it as you intended...." In the 1990s, when I was at Motorola SPS here in Austin, we had a mixed-OS workplace. Some folks had PCs, some folks had Macs (and this was before the Mac OS got ported to BSD Unix), and some folks had a Unix variant. Generally, all the production documentation was done in Framemaker. Now, the character mapping for identically identified fonts was slightly different between all three OSes. So if you inserted an omega for ohms in Unix, the Mac version would dutifully change it to a "w". Always, And we sent Mac-generated PDFs to our dead-tree publishing house. Guess how many times I caught that error at pre-press? I'll tell you. Every time. Guess how many times it got fixed? Well, I was a senior tech writer and the only person on our publishing side who had ever touched a resistor. So when it went from my desk straight to our proofreader, it was correct. Every other time, it was wrong, and we published a whole lot of stuff that said that an IC smaller than a thumbtack had a "50 w" output. And then there was the Ph.D. EE and senior fellow in a few different places who told me that one of our 16-bit DSP chips smaller than a postage stamp contained an 8 Henry inductance on its input. Because his simulation said so. He had never seen an 8 hy impedance device in his life. He was too stupid to learn anything from a secretar -- er, tech writer. I thought about finding a labeled 8 hy input filter choke and dropping it on his desk one weekend, but I didn't have one in my junkpix at the time. God, it's good to be retired. 73 Jim N6OTQ
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John Kolb
Dr. David Kirkby, Kirkby Microwave Ltd
