Questions tagged [electricity]

The study of the presence and flow of electric charge. Charges, currents, fields, potentials. It has also sub-topics such as voltage, current and resistance.

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Why is Power in an electric circuit equal to VI? [closed]

Where did this formula come from? Everyone I asked just told me to substitute values of in ohms law to derive this but no one told why is power equal to voltage * current. Part of the reason for this ...
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How sensitive was the frog galvanoscope?

Frog galvanoscope is an instrument for detecting small voltages, made of a frog's leg. Wikipedia notes: The instrument is capable of detecting extremely small voltages, and could far surpass other ...
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Translation of Cabeo's Philosophia magnetica

Is there a translation of Niccolò Cabeo's work Philosophia magnetica into English (or other modern language)? The original text in Latin is available for example here but I can't find any translation (...
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Early sources for surface and bound charges in polarization

I am looking for early sources (references) to the analysis in electrostatics where the polarization vector is rewritten in terms of bound charges and a surface polarization charge. In terms of what I ...
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Early triboelectricity

I am looking for good sources to quote for early work on triboelectricity. I already have the standard ones, e.g. Benjamin Park (1898) "A history of electricity..", Roller & Roller (1953)...
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Granville Wood's Telegraph -- do we know the data rate and range?

I realize this is more a history of engineering question but I do not see a SE devoted to this so I thought I would ask here. https://suiter.com/granville-woods-railway-telegraphy-patent-no-373383/ ...
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How did Thomson claim that charge on hydrogen ion was equal to charge on electron without knowing charge on electron?

From "The Electron" by J. J. Thomson, published in The Scientific Monthly Vol. 20, No. 2 (Feb., 1925), pp. 113-115 https://www.jstor.org/stable/7115 [Continued discussion] previously ...
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Why were Cathode ray tubes first invented?

Cathode ray tubes have played a very important role in the development of physics around 1900. They have also served as a key component in old-fashioned TVs. This is great and all, but what was the ...
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What was the first use/cite of "Watt's law"?

Yesterday I saw a reference to Watt's law being used for the power formula P = V I. It's been over 40 years since I learned my basic electrical engineering fundamentals and this is the first time that ...
Daryl_71's user avatar
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How was the direction of current flow determined in the first battery or the first voltmeter?

I read Franklin started the positive negative naming convention of electricity. Now early scientists had to pick a direction for the battery and voltmeter. I don't understand how this was done. If you ...
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Published expository account of Franklin's work on electricity?

Is there a good (or even mediocre) published expository account of Benjamin Franklin's work on electricity? From what I have read and heard, it appears that Franklin may have been the first to ...
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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?

I have searched in Internet, but I have not found the material. It couldn't be copper, because a short circuit would occur, and it couldn't be Nicrom, because Nicrom was not developed until 1905, and ...
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Why is the magnetic force on a current-carrying wire sometimes called the Laplace force?

Educated in the UK, I've been used to calling the force on a current-carrying wire in a magnetic field 'the motor effect force'. But I'm increasingly aware of another (less clumsy?) name for it: 'the ...
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How was it determined that charge and current were made of the same stuff?

Even in my earliest physics course we took for granted that charges are made of electrons (or their absence) and currents are due to the motion of electrons. But the electron is a very modern concept ...
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What is the "Pix Hispana" that Niccolo Cabeus refers to?

In Niccolo Cabeo's 1629 work Philosophia Magnetica, in which he picks up on Gilbert's early electrical work in book 2, he lists a number of materials that can be electrified (book II. ch. XVII., p. ...
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In the early days of electricity did people think in terms of a big electric motor in the loft

I remember reading once that when electric motors first became available for household use, people thought that there would be one big motor in the loft, with drive belts feeding devices in different ...
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Which scientist(s) first measured the elementary charge and how did they do it? [duplicate]

I would be grateful if anyone could shed some light on these questions. Which scientist(s) first measured the elementary charge? If it wasn't measured in a straightforward experimental setting, and ...
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How did Kirchhoff express his voltage law (KVL)

It is sometimes claimed that Kirchhoff's Voltage Law (KVL) is equivalent to the statement that a given electric field is conservative. Or, put another way, is is sometimes claimed that KVL is ...
Math Keeps Me Busy's user avatar
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History of experimental verification of the identity of voltaic and static electricity and references

What where the crucial experiments which showed the identity of voltaic and static electricity? How did the experiments work in detail and what are the original references for it? In "A History ...
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How we distinguished charges and named them?

As I searched history of nomenclature of charges I got this.., Ben Franklin imagined electricity as a type of invisible fluid that could build up or be absent from a material, or at least certain ...
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Was Johann Heinrich Winkler really the first person who discovered field emission?

Who are the person or people who really discovered field emission in the first place? According to this slide https://www.researchgate.net/publication/...
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Are there any descriptions of the reluctance motor invented by W.H. Taylor in the 1800's?

I could not find any descriptions of the first motors of W. H. Taylor in Wikipedia of any reference, history or circumstances surrounding its invention. Apparently the motor was never used for any ...
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How did J.J. Thomson learn that what he discovered was different than an atom or a molecule?

Wikipedia says he discovered that the electron was different than an atom or molecule. His line of reasoning is not shown. I additionally searched stack exchange and unless I missed it..... I am lost ...
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Was the wide use of mercury in experiments in the 19th century related to alchemy?

We know that Newton's hair samples showed high level of mercury and of course he used mercury like crazy in his alchemy experiments (as did many/all alchemists not just in the west but also China) and ...
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Are "galvanic" and "voltaic" synonymous?

The OED defines galvanism (coined ~1792) as Electricity developed by chemical action and voltaic (coined ~1813) as Used in producing electricity by chemical action after the method discovered by ...
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What is the original source of the problem of finding equivalent resistance between two nodes in an infinite grid of resistors?

A famous problem in electronics or physics course,is the following--- Consider an infinite 2d grid of resistors having resistance of equal value.Find the resistance between any two nodes in the grid. ...
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What is the history of electricity [closed]

Could someone please explain how the concept of electricity was originally conceived and how it became connected with time? Also how did people come about the relationship between time and electricity?...
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Where did the names positive and negative for the early voltaic piles come from?

The early voltaic pile has cells consisting of a [copper||electroltye||zinc] unit, and then another, so all of the zinc->copper junctions are metal-on-metal and all of the copper->zinc junctions are ...
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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?

My problem is my lack of knowledge on the historical development of the constant used for the permittivity of free space. I know instead of asking the question I should read Wiki on the history of "...
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Where can I get early 20th century books on electronics and mathematics?

I have been searching for books on electronics and mathematics of early 20th century.I found a link which was released in 1950 but that was in russian language.Can I find these books in universities ...
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Why volt instead of volta?

Why is the volt not identical to the full name Volta, unlike the other electrical units ohm, ampere, coulomb, tesla, weber and henry? Is there a historical explanation, was the volt introduced at a ...
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Was it suspected that the speed of electricity was equal to the speed of light?

Was it believed early on that signals sent via wire moved at exactly the speed of light or simply very fast? Who was the first to estimate the speed? EDIT: Given that they move at less than the ...
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How was (non-instantaneous) electric current first discovered?

How was (non-instantaneous) electric current first discovered and what were some of the main first thoughts on it?
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Why does 'Wheatstone bridge' carries Wheatstone's name when it was invented by someone else?

Wheatstone Bridge was invented by Mr. Samuel Hunter Christie. So, How come it carries Mr Charles Wheatstone's name? I would like to know what each of them contributed toward the 'Wheatstone bridge' ...
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Who changed $i$ to $j$ in electronics?

In electronics, $j$ is used for a square root of $-1$, because $I$ is current. Who introduced this and when? And was it really necessary, given that (at least now) current's symbol is capitalised? ...
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Hydrogen electrode and its electrode potential

In electrochemistry, all electrode potentials are quoted with reference to the standard hydrogen electrode. Its value is assigned to be 0 volts. I have been searching for the origin of this convention ...
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What experiments led to the sign of the electron's charge?

The famous Millikan's oil drop experiment in 1908 determined the magnitude of charge of the electron to be 1.59*10^(-19) C. However, it was well known that electron has a negative charge. Although ...
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High voltage / current sources in 19th century cathode ray experiments

In modern chemistry textbooks, a DC source (battery symbol) is usually shown for cathode ray tube experiments by Thomson and others. Certainly, no battery can provide very high voltages needed for gas ...
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Charge concept before discovery of electron [duplicate]

How did the concept of positive and negative charge originate before the discovery of an electron? My question is related to the historical aspects.
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How was it discovered how many electrons are in one coulomb?

I understand the SI meaning of a Coulomb but how were the individual electrons counted in the measurement to know how many it would take to constitute a Coulomb?
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How did Reginald Fessenden realize that spark-gaps could generate waves and the modulation of those waves with voice?

I can somewhat understand how the spark-gap was devised to transmit waves and how the waves were first measured in frequency but what lead to the idea of "modulation" where another electrical signal ...
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How did people measure electric charge at the time of Coulomb?

Around the time that Coulomb gave Coulomb's law, how did people measure electric charge?
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Origin of the coulomb and ampere

What is the historical origin of the size of the coulomb (and in turn, ampere)? Currently (pardon the pun), the coulomb is defined in terms of the ampere. The ampere is in turn effectively defined by ...
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Concept of electric flux

Just curious about the history of electric flux -Flux- I am aware of the fact that flux, on its own is a mathematical concept but how did it find its way into physics. Was it just introduced to ...
user203747's user avatar
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What inspired Nicholson to break water into hydrogen and oxygen with electricity?

It seems a bit of a stretch to go from a battery to electrolysis but this fellow appears to have thought of it only a few weeks after Volta invented the "pile" battery. I am wondering if he knew ...
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Question about Gauss's contributions to the theory of electric circuits

This question is a continuation of my previously-posted question: Several questions about Gauss's contributions to electromagnetism. I wrote it after user vonbrand asked me to split my original ...
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Was the telegraph system of 1859 powered by AC or DC and how extensive was it?

I was actually curious how the Solar Coronal event of 1859 known as the Carrington Event affected the telegraph system. Wiki does not seem to have much detail of this but there is mention of it in a ...
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Resistor color code

I wonder if anyone would know the origin of the Resistor Color Code.
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What did Westinghouse use for power to drive Tesla's generators during the 1892 World's Fair

I did manage to find technical drawings of the World's fair after considerable searching but probably I am not savvy enough to find the right items. In one of the drawings it does show what appears to ...
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Who originally derived the general force law equation of force between current elements?

Wikipedia credits this to Maxwell. This derivation can be found in Maxwell's Treatise on Electricity and Magnetism vol. 2, part 4, ch. 2 (§§502-527). I went through the derivation and found two self ...
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