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Admit your Brain lock
Sredni:
In an electromagnetic circuit, the EMF is the line integral of the induced (nonconservative) electric field; voltage on the other hand is the line integral of the total electric field and is the sum of the scalar potential difference (line integral of the conservative part of the electric field) and the EMF contribution along that path.
Sorry, I could not help myself.
I felt like Roger Rabbit when someone is singing "shave and a haircut"...
IanB:
--- Quote from: Siwastaja on April 05, 2024, 06:56:48 pm ---Motor control theory for example is full of what totally looks like obfuscation, even if it's originally unintentional. Think about concept of "electromotive force", which is often shown with ANY of these symbols:
E
EMF (which could be confused to being E*M*F)
U
V
u
v
And guess what - it isn't a force at all, which is made more confusing by the fact that force is a related concept (e.g. in a linear motor, very directly).
But "electromotive force" already has a modern name: all you had to do is to call it voltage and use either U or V, the two most common symbols for voltage. And when you are trying to grasp motor control theory in whole, having such basic concept as fucking VOLTAGE obfuscated to some magical "new concept" is going to be a huge time sink. Same can be said about stuff like flux linkage. Linkage what? Flux linking something to something..?
--- End quote ---
--- Quote from: Sredni on April 05, 2024, 10:09:29 pm ---In an electromagnetic circuit, the EMF is the line integral of the induced (nonconservative) electric field; voltage on the other hand is the line integral of the total electric field and is the sum of the scalar potential difference (line integral of the conservative part of the electric field) and the EMF contribution along that path.
Sorry, I could not help myself.
I felt like Roger Rabbit when someone is singing "shave and a haircut"...
--- End quote ---
Notwithstanding my earlier comment, it is possible to shed some light on the choice of symbol used for EMF.
In electrochemical thermodynamics, the following formula may be found for the change in Gibbs free energy:
$$\mathrm{d}G=-S\mathrm{d}T+V\mathrm{d}P+\mathcal{E}\mathrm{d}Q$$
In which \$G\$ is Gibbs free energy, \$S\$ is entropy, \$T\$ is temperature, \$V\$ is volume, \$P\$ is pressure, \$\mathcal{E}\$ is EMF, and \$Q\$ is charge.
We find here a dilemma, since in thermodyamics \$E\$ is already taken for total energy, \$V\$ is taken for volume, and \$U\$ is taken for internal energy. All the regular letters are therefore already accounted for, and using \$\mathcal{E}\$ for EMF becomes a somewhat forced choice.
Sredni:
I use double struck capital letters for Energy , Power, potential energy (U) and kinetic energy (T), work and a few others. They stick out pretty well.
tggzzz:
--- Quote from: DiodeDipShit on April 05, 2024, 07:33:30 pm ---Which Witch is which? Which troubled those witches in Salem?
Here Yee.... Hear Yea? Yes You, come here, here me !
Coke or Pepsi? Pass the Mirror.
Where is the ware on your wear? My Underwear. Where?
Regional Dialects play havoc with foreign language. eh. Oui oui.
Opinions matter, what's it matter? Matter of fact, Dark Matter matters.
Pardon me, do you have any Grey Poupon? No, I poop fine. I meant mustard. Sorry, I only speak French.
I order you ! Aye Aye Captain. Then an eye for an eye? Alas, Aye sailor. Aye Yai Yai ! ! !
This court is out of order ! Orderly, order for takeout. Is that and order?
B, B, R, O, Y, G, B, V, G, W
You can't say that ! O I B C'N U ....... next Tuesday
--- End quote ---
For a more, um, accomplished exasperated variant of that, I refer you to this old chestnut: http://ncf.idallen.com/english.html or the version I posted here https://www.eevblog.com/forum/blog/perverse-language/msg607129/#msg607129
CatalinaWOW:
In some sense these last couple of pages have been a variant of "Why can't we all just use the same words for everything." It would be so much easier if everybody just spoke English, or Chinese or Spanish or whatever. Much of the confusion described here comes because many different fields of expertise developed as independent islands. Whether that island consisted of a technology area, a university group, a scientific society or geographical unit doesn't matter. They developed conventions that made sense in the context, and passed those conventions on to their own peers and successors.
The term interdisciplinary only became popular in the last 50 years or so. The reality of interdisciplinary work has caused overlap in the conventions. But no one who has spent half their career steeped in one convention enjoys the idea of uprooting for another. The convention they grew up with isn't confusing to them, the new one is, and seems an attempt to upset the applecart.
The only way a unified symbology and terminology will take over is if the benefits seem to outweigh the drawbacks (Reprinting textbooks, retraining existing practitioners, time invested in trying to unravel all of the different needs and objectives). I don't object to the process, but don't see how pejoratives such as obfuscation contribute to the solution.
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