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60 votes
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Why volt instead of volta?

The volt, ohm and farad were introduced by the same person, Latimer Clark, a cable engineer, in a paper in 1861. He started the tradition of naming units after scientists. He initially distorted all ...
jkien's user avatar
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12 votes
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Was it suspected that the speed of electricity was equal to the speed of light?

For a long time it was not only believed but even ascertained that electric signals moved not just as fast but faster than light, even "instantaneously". The original experiments involving ...
Conifold's user avatar
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10 votes
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What inspired Nicholson to break water into hydrogen and oxygen with electricity?

Mander's Carnocycle blog has a post Carlisle, Nicholson and the discovery of electrolysis with a detailed account of the story. I will only give the highlights. On March 20th, 1800 Volta wrote to ...
Conifold's user avatar
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10 votes

Where did the names positive and negative for the early voltaic piles come from?

The "decision" came from Franklin c. 1750, and predates voltaic piles. Franklin followed the one-fluid theory of electricity proposed by Watson in 1746, and explained electric discharges in ...
Conifold's user avatar
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9 votes
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How did J.J. Thomson learn that what he discovered was different than an atom or a molecule?

Thomson drew his conclusion based on his calculation of the charge to mass ratio of the "corpuscular carriers of negative charge in cathode rays". Quoting Thomson's Nobel Lecture of 1906: ...
nwr's user avatar
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8 votes

Origin of battery symbol?

Yes, it was derived from the looks of voltaic batteries. More generally, the early symbols for circuit diagrams (cell, resistor, capacitor, etc.) were based on the physical appearance of the devices ...
Conifold's user avatar
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8 votes

Who originally derived the general force law equation of force between current elements?

Ampère did. Ampère's force law (not to be confused with one of Maxwell's equations, "Ampère"'s circuital law, which Ampère never wrote down, as Ampère didn't deal with the field concept), written in ...
Geremia's user avatar
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7 votes
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Was the telegraph system of 1859 powered by AC or DC and how extensive was it?

Google really is your friend. history.com says E.W. Culgan, a telegraph manager in Pittsburgh, reported that the resulting currents flowing through the wires were so powerful that platinum ...
Carl Witthoft's user avatar
7 votes
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How sensitive was the frog galvanoscope?

A frog galvanoscope does not measure voltage. Instead it detects electricity that same way that I detect my static charge after walking across a carpet in winter - by a short current flow. The current ...
David Bailey's user avatar
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6 votes
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Resistor color code

The color code was developed in the 1920's by the Radio Manufacturers Association (RMA) as a three band code for resistor values. The three bands were more compact than the number value because the ...
jkien's user avatar
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6 votes
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What did Einstein learn in his university electricity and magnetism courses?

Einstein's physics teacher, H. F. Weber, apparently did not teach him any Helmholtz, as Einstein wrote in a 10 August 1899 letter to Mileva Marić: I returned the Helmholtz volume* and am at present ...
Geremia's user avatar
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5 votes

High voltage / current sources in 19th century cathode ray experiments

In order to obtain a nonpulsating power source some early investigators used Wimshurst or similar static electricity generators, or batteries of many small storage cells. (The discovery of the ...
jkien's user avatar
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5 votes

How was (non-instantaneous) electric current first discovered?

I will assume "non-instantaneous" means something other than electric discharge in the atmosphere, from animals like eels and torpedo fishes, or electrostatic generators like the Leyden jar or the van ...
Conifold's user avatar
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4 votes
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Who changed $i$ to $j$ in electronics?

The symbol i is still used in mathematics; j is an invention of an electrical engineers, usually attributed to Charles P. Steinmetz. See for example Introduction of $\imath$ and $\jmath$ notations for ...
AChem's user avatar
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4 votes

Where did the names positive and negative for the early voltaic piles come from?

You are indeed right, these two signs (+) and (-) have confused generations of scientists. I have searched for more than 10 years on Volta's assignment on the signs of battery terminals. I will ...
AChem's user avatar
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4 votes
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How did Kirchhoff express his voltage law (KVL)

Kirchhoff's Voltage Law appears in his 1845 paper "Ueber den Durchgang eines electrischen stromes etc." wenn die Draehte $1,2,...\nu$ eine geschlossene Figur bilden, $$I_1\omega_1 + I_2\...
Math Keeps Me Busy's user avatar
4 votes
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What material was the wire with which J.P. Joule did his experiment, with which he arrived at his law of heat dissipation from a resistor?

"It couldn't be copper, because a short circuit would occur" Not if the copper was in the form of a long thin wire. Solenoids, for example, are coils of enamelled copper wire and are usually ...
Philip Wood's user avatar
3 votes
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Hydrogen electrode and its electrode potential

According to the Royal Society of Chemistry site, the hydrogen electrode was discovered by Max Le Blanc. Chemists like Max Le Blanc to begin to plot ‘polarisation’ curves to investigate the ...
nwr's user avatar
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3 votes
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What experiments led to the sign of the electron's charge?

I think we have an answer. The original paper is in French by Perrin. The translation is in Nature (1896). NEW EXPERIMENTS ON THE KATHODE RAYS Jean Perrin. It is a two paged article. https://www....
AChem's user avatar
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3 votes
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What did Westinghouse use for power to drive Tesla's generators during the 1892 World's Fair

The Tesla Society has a photo of a "Allis-Corliss Engine." Wikipedia identifies this as a large steam-powered engine. And over at vintagemachinery.org, it is stated explicitly that The duty of ...
Carl Witthoft's user avatar
3 votes

How did people measure electric charge at the time of Coulomb?

People did not. They generated and stored static electricity, but measuring it, other than by how strong the electic shock felt, was not yet done. Coulomb was the one who invented a way to do it in ...
Conifold's user avatar
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3 votes

Origin of the coulomb and ampere

my question: why is the coulomb (and ampere) the size it is today, which an outrageous size that makes it impractical for direct use? The coulomb has that value because in the mid 19th century ...
jkien's user avatar
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3 votes
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What was taught in 19th century European electricity and/or magnetism courses?

Some data: The plan for the famous 1867 textbook Treatise on Natural Philosophy by William Thomson (Professor of Natural Philosophy at the University of Glasgow for over 50 years) and Peter Guthrie ...
Mauro ALLEGRANZA's user avatar
3 votes
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Why is Maxwell and not Ampère credited for unifying electricity and magnetism?

On my opinion, the following citation from Poincare answers this question: “At the time, when Maxwell initiated his studies, the laws of electrodynamics adopted before him explained all known ...
Alexandre Eremenko's user avatar
3 votes
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Did James Clerk Maxwell derive the permittivity of free space from his "Maxwell's" equations or was the parameter already known by him?

This answer is a repost of a comment of Conifold on the question, which the asker indicated gave a satisfactory answer to their question: Wiki's History of Maxwell's equations implies that the ...
3 votes
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Are "galvanic" and "voltaic" synonymous?

Not really, although they broadly referred to the same phenomena. Galvanism was associated with a particular view that ascribed special powers to living organisms in producing "animal electricity&...
Conifold's user avatar
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3 votes

How did Kirchhoff express his voltage law (KVL)

We can read the original article that Kirchhoff published on Annalen der Physik und Chemie 1845, Band LXIV with the title "Ueber den Durchgang eines elektrischen Stromes durch eine Ebene ins ...
Sredni Vashtar's user avatar
3 votes
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What is the "Pix Hispana" that Niccolo Cabeus refers to?

Pix or pitch made from the resin of various coniferous trees was in common use since antiquity, and variants of this substance, often named after their place of origin, were described by Roman writers ...
njuffa's user avatar
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3 votes
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How was the direction of current flow determined in the first battery or the first voltmeter?

Too much to change. Every single book, paper, instruction manual, or anything else that referred to the poles as negative and positive would have been switched. Furthermore, anything old, if not ...
Mary's user avatar
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2 votes
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Where in Gauss's works does he derive "Gauss's Law"?

The law was first¹ formulated by Joseph Louis Lagrange in 1773,² followed by Carl Friedrich Gauss in 1813,³ both in the context of the attraction of ellipsoids. Notes¹ Pierre Duhem's Leçons sur l'...
Geremia's user avatar
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