# Why there is no “Edison” unit in physics? [closed]

In the popular culture the XIX-XX century competition between Thomas Edison and Nikola Tesla is well-known. The example could be the Prestige movie, where there are some "Edison's agents" who sabotage Tesla's efforts. From electrical engineers' point of view the most known problem between them is whether to use DC or AC (the War of Currents).

We can say that Edison is better known, because of the invention of a bulb or his first urban electricity system. Tesla is almost unknown, some people say about magic and so on. (That's why I recall the Prestige movie.)

In electricity it seems that Tesla has won, even if he's widely forgotten. We use AC mainly because of it's easy in transformers. We have an SI unit $\text{T}$ (tesla), which is for measuring magnetic induction.

But -- we can't forget Edison's impact on electricity. Even if he was mostly a great businessman, no-one can say he's done nothing but the bulb. Here is some list of his patents.

So why isn't he honored (like Tesla, Ampère, Volta, Siemens, Ohm, Faraday, ...) by his "own" unit in physics?

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## closed as not constructive by dmckee♦Apr 11 '13 at 1:03

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What would this new unit measure? Everything that Edison could possibly have measured already has a standard unit and introducing a new one would just be a confusing redundancy. – Michael Brown Apr 8 '13 at 11:37
@MichaelBrown I don't know, there is a Tesla unit and it's for magnetic induction. I don't say that we should insert a new unit because we like Edison, but I'm sure there is something to measure that this could be used, maybe in acoustics (as he invented phonograph). Maybe electromagnetical field, so 1 Ed = 1 V/m or anything else, it does not matter. – Voitcus Apr 8 '13 at 11:51
This is only speculation so I won't post it as an answer. Edison had numerous companies named after him, and in fact Southern California Edison, at least, is still a going concern. At the time when the Tesla unit was introduced (1960, according to Wikipedia), if an Edison unit were under consideration the Edison companies might have objected on trademark grounds. – The Photon Apr 8 '13 at 21:32
" Tesla unit and it's for magnetic induction. " Er...almost. It's a unit of magnetic field strength. The SI unit of induction is the Henry. – dmckee Apr 11 '13 at 1:00
Regarding The Prestige, this is one of the worst possible references on Tesla. Nearly every detail related to Tesla in the movie is factually incorrect. – Tom Harrington Mar 31 '14 at 18:13

Patents are for inventions, which are feats of engineering, not advances in physics. Edison was a great businessman as well as a great inventor: he took understood principles of physics and turned them into useful machines. These machines are codified in the patents. He did not, however, contribute to the understanding of the laws of physics.

Now, admittedly, Tesla did not advance our understanding much either. He, too, was predominantly an engineer/inventor. However, by experimenting with high-voltage current, X-rays and radio waves, he indirectly helped our understanding of electromagnetic radiation and the electromagnetic force.

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So was Werner von Siemens, even less, I think. – Voitcus Apr 8 '13 at 12:06
And he had 2 units named after him: sizes.com/units/siemens.htm – Gnubie Apr 18 '13 at 14:07

Since Helen, whose face could launch a thousand ships is the unit of beauty (as in a millihelen is a face that could launch one ship), perhaps Edison could be the unit of jerkishness. I base this, of course, on an entirely unbiased source.

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He could be the unit of the third derivative of displacement. – Ataraxia Apr 8 '13 at 12:28
I don't mean that Tesla was bad and Edison was good, or vice versa. I agree that Tesla was much more inventor. I'm just wondering why Edison, who in popular culture is some kind of guru, was not honored as a great physicist. Could this be possible that's some revenge of Tesla's fans? Because he had to feed pigeons at his late age? – Voitcus Apr 8 '13 at 13:19

$$1~\text{edison}=100~\text{A}$$ It's on the Internet and therefore true. However, it doesn't appear very widespread.

Edison ($\text{edison}$) is a unit in the category of Electric current. It is also known as edisons. Edison
($\text{edison}$) has a dimension of $I$ where $I$ is electric current. It can be converted to the corresponding standard SI unit $\text{A}$ by multiplying its value by a factor of $100$.

eFunda: The Ultimate Online Reference for Engineers

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Does it apply to alternating current, or direct current only? ;) – Michael Brown Apr 8 '13 at 14:53
@MichaelBrown Either way trade mark royalties apply to the use of $\text{edison}^®$. :) – Keep these mind Apr 8 '13 at 18:45
Yeah, there's also a googol that -- of course -- is named after the Google :-) (@MichaelBrown your comment is great) – Voitcus Apr 8 '13 at 19:33

He invented stuff, not physics ideas. Because of that, we have the Edison Screw, which is still the standard "light socket".

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I don't quite agree that inventors can not have their units in physics. Some examples are James Watt, Werner von Siemens, Alexander (deci)Bell. However, I agree that mostly people who gave their names to units were rather physicists than engineers. What we can think about Edison, was he a thief or not, his phonograph was the first device to record sound -- I think it is large milestone in science. – Voitcus Apr 8 '13 at 19:45
@Voitcus: This is not correct. His was the first able to play back a sound it previously recorded. The first sound recorder seems to be the Phonautograph, patented in 1857 by Édouard-Léon Scott de Martinville. Some of his recordings were played back in 2008. You can look it up, e.g., in wikipedia. – Yvan Velenik Apr 9 '13 at 7:20