v for frequency?

(I assume "tan" is a typo for "than", rather than the trig function!)

I can see an advantage in abbreviating "c/s" to "Hz", especially when it is spoken aloud - "482 mega hertz" is shorter than "482 mega cycles per second".

Are there any other SI units which are abbreviations for the reciprocal of another SI unit? I suppose there's mho for conductance which is 1/R (in ohms) and written as an upside-down omega. But that's not as widely used.

The notation that always jars with me is the use of negative powers in place of "per". My Nuffield Physics O/A level books always referred to speeds in m.s^-1 and accelerations in m.s^-2 (where "^-1" denotes a superscript "-1" etc. The teacher was undecided as to how you pronounced that: was it "metres seconds-to-the-minus-1" or "metres per second"?

Negative superscript units always seemed to be a gimmick too far.

And then we get onto the thorny issue of "traditional" versus IUPAC names for chemical compounds - acetic versus ethanoic acid, isopropyl alcohol versus propan-2-ol: the traditional names are more familiar but the IUPAC names are more systematic and more accurately represent how the atoms are arranged. Familiar versus Sunday-school names ;-)

But the ultimate "grates like chalk on a blackboard" usage for me is kilometre pronounced "kill-OMM-i-TAH" when all other SI prefixes and units have the stress on the first syllable "KILL-o-ME-tre" (as for "MIcroMEtre", "MEGaMEtre" etc). It's hilarious to hear Prof Brian Cox flipping between "kill-OMM-i-TAH" which his director has probably told him is the trendy pronunciation and "KILL-o-ME-tre" which he always used in scientific and engineering work - sometimes he does it from one sentence to the next.

I once worked with a guy who used the trendy pronunciation for lengths of running races or distances along roads, and the scientific pronunciation for units in scientific/engineering contexts.

"On our constants and equations sheet, the italicized v stands for the greek letter nu, which is the variable for frequency. The regular v stands for velocity. On that sheet specifically, c = λ v and E = hv are the only equations that use the greek letter nu (frequency). Hope this helps!"

This makes my brain Hertz.

Brian

Mine too. I still say cycles more than Hertz. Just as I often say 110 instead of 120 which is more like 125 volts now. Guess we need to rename or put a name on standard line voltages. Just call them Angie, bill, Carol for the 120, 240, 480 volts !!!

For conductance (1/R), suspectance and admittance (1/Z) the unit is Siemens (S).

Ah yes, I'd forgotten that siemens is the new name for the unit that used to be called mho.

I just use f.

That's because you're a Merkin and can't name anything correctly. I bet you say counter clockwise!

Pitiful. Standard 240V all over my house, just the one voltage, just the one style of socket, 13 amps at every socket. Over 3kW for any device you can plug in anywhere. I don't need a special circuit for a dryer.

That sounds like what Apple do. Is Leopard or Tiger the newer version of the OS? Who knows?

The Leopard is newer that the Tiger. Oh, you're talking about OSs, not Panzers.

I've never heard of nu (italic v) being used for frequency in all my O-level, A-level and university electronic engineering studies. Only f or omega, where omega = 2 pi f

omega is called angular frequency.

And, being an elec eng, I use j (rather than i) to denote sqrt(-1), since i tends to be used to denote instantaneous current. I once worked with a guy called Bill Taylor whose initials were J W T (James William Taylor). He was known as "J-Omega".

It's generally used for light and frequencies higher than you might design for:

Yes.

The maths element of degrees in the UK have generally been taught by mathematicians who would use 'i'. Most would be then be familiar with the duality of symbols.

I use something similar I use Imperial units (Miles, Feet etc) for distances along roads peoples sizes etc, but Metric ( Centimetres Millimetres etc) for scientific/engineering contexts .

What are Imperial units????

I was brought up in the MKS and CGS system....

v is used in Physics, not electronics. E=hv being the one I can remember. It may be relating the energy in photon to its spectral frequency

and I remember E = hc / Lambda

so c = lambda x v

where m is the speed of light in ms^-1, Lambda is wavelength in metres and v is the frequency in Hz or s^-1

That's a German manufacturing company. WTF was wrong with the mho?

And I think you meant susceptance. You were suspecting it was conducting?

Am 21.03.23 um 01:27 schrieb Commander Kinsey:

No. Wernher von Siemens was one of our pioneers, like Tesla, Marconi, Ohm, Ampère. I was at his grave in Berlin-Kreuzberg. Quite modest. I would have expected more for the founding father of one of the world's most important electrical companies. Like a fresh flower or two.

Gerhard

In the UK "Imperial Units" refers to miles, feet, pounds, pints and suchlike. Noting that the imperial means British Empire, and the pint is

I was taught in MKS, but imperial units were still in common use. Which meant that if I put my hand in some water I'd feel 20C, but the air around it would be 68F and I'd have to think to work out which was warmer :)

Andy

In message snipped-for-privacy@ryzen.home, Commander Kinsey snipped-for-privacy@nospam.com writes

I'm of the same mind about the introduction of 'new' units. While I certainly don't advocate using (say) volts-per-amp instead of ohms, I find myself feeling rather silly when I have to ask, "WTF is a 'Siemen'? If their introduction is not resisted, the possibilities for puzzlement and confusion are endless, eg what could we call a foot-per-second, or a mile-per-hour?