Talk:Volt

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Removal of the final 'a'

One thing I've always wondered about is why the unit is called "Volt" instead of "Volta". This seems the only case where the original scientist (sur)name is not used exactly as is for the unit of measure. Does anyone know? --Gennaro Prota 01:30, 7 January 2006 (UTC)

The farad is another, which was abbreviated because "faraday" was already taken. Ampere is often abbreviated to amp, perhaps similar logic was used for volt. --Hyperneural 02:04, 22 March 2006 (UTC)

farad is similar, yes; but "amp" is not, as the unit name is still "ampere". Before posting here I did some investigations and found an Italian document reporting the following:
volt: from the Italian physicist Alessandro Volta - the ortographic and phonetic contraction was deliberated [sic!] by the BIPM during the meetings held in Scheveningen (Netherlands) and Bruxelles on 17 and 30 June 1935.
Unfortunately the meetings are so old that I doubt their minutes (supposed that they included a rationale) have been transcribed in electronical form. In any case I didn't find them. Should you find more info, please inform me! This is a question that lasts from my childhood :) --Gennaro Prota 04:26, 22 March 2006 (UTC)
I found some interesting info reguarding this. I believe the date found by the above anon poster was actually the date the tried to standardize the volt as being a J/C. It looks like the British Association for the Advancement of Science('BAAS') proposal was utilized by the first International Electrical Congresses('IEC') to establish the volt as a unit of emf. [1] The question now remains to find the full details of the preceedings of the first(or first few) IEC Kevin_b_er 02:43, 2 June 2006 (UTC)
Pardon me but... who is the anon poster? :) —Gennaro Prota•Talk 15:49, 2 June 2006 (UTC)
I am curious about the Volt/Volta change and reasoning as well. If anyone knows, please talk discussion on my wik page *grin* Vid2vid 23:34, 20 June 2007 (UTC)
Another example, the bel is named after Alexander Bell. Rsduhamel (talk) 06:46, 26 December 2011 (UTC)

Rewordings/adjustments for non-engineers

This article, and those of amps, watts, etc, is very precise and I'm sure it is good reference material for engineers However as a non engineer I didn't really get anything out of this. It seems to assume knowledge of the theory of electricity and power, which I don't have.

Some good questions to answer:

  • How does a volt relate to a watt? An ampere?
  • What sorts of ranges of voltages are found around the world in various devices and why?
  • Are volts a concept or a thing?

Each of these questions needs to be answered in English, not equations. The text should not rely on me following a series of links in order to understand it (which is currently the case), but be explanatory while providing links for more detailed or technical information.

  • how does a volt relate to a watt? in english? that's a tough one.  :-) a watt is a measurement of the amount of power (physics) that is being transferred from one place to another. the ampere is a measurement of the amount of charged particles moving from one place to another. the relationship between the three is an equation. i can't think of any other way to put it. what is the relationship between inches and pounds in english with no equations?
  • lots. domestic power lines are in the hundreds of volts, distribution power lines are in the thousands, particle accelerators are spoken of in terms of millions of volts(?), the bioelectricity on your scalp from the functioning of your brain is in the microvolts.
  • it's a measurement. not sure which of your choices that falls under. it can be thought of as a measurement of "electron pressure".
can anyone else do better? - Omegatron 22:49, Mar 8, 2005 (UTC)
yeah. the first sentence of the voltage (potential difference) article is pretty awful...  :-) - Omegatron 22:52, Mar 8, 2005 (UTC)
You can try to think of something that you can relate to. For example, "work" is done when you are pushing a heavy box across the room. Energy is invisible, but you can easily see the amount of "work" done. So you can say it takes that many calories to move the box that far. Same with voltage, you can ask this question: how much energy is needed to move an electric charge from Point A to Point B?

New standard format?

Discussion moved to Talk:Units of measurement

Hydraulic analogy

Re: "water circulating in a network of pipes, driven by pumps in the absence of gravity, then the potential difference corresponds to the hydrostatic pressure difference between two points". The "hydrostatic pressure" hyperlink is redirected to "fluid pressure", perhaps because "hydrostatic pressure" is more narrowly, and I presume correctly, defined there as the pressure of a fluid due to the weight of the fluid, which makes the "absence of gravity" correspondence to "hydrostatic pressure" on the "Volt" page problematic. Perhaps the simple solution is to change the linked reference text from "hydrostatic pressure" to "fluid pressure"? I am new to both Wiki and physics, and perhaps there is more to this than I can see, but for anyone simply following the linked text, there is I think a problem. jauntymcd@sprint.ca Oct 22, 2005

I changed to fluid pressure, as above. I also removed most of : "Voltage is a convenient way of quantifying the ability to do work without having to specify the amount of charge (the number of electrons or other particles) involved. This simplifies electrical calculations, where the number of particles that move is usually of no interest." I don't think it is helpful. The amount of charge might be relevant in talking about the voltage across a capacitor, but the voltage induced across a conductor by a changing magnetic field has nothing to do with quantity of charge.--agr 11:25, 2 December 2005 (UTC)

W/ some minor exceptions, this is a good discussion of voltage. However, there is nothing as to what voltage is rigorously. What is it about certain electrons that makes them different from others of lower/higher voltage?

Voltage is a property of an electric field, not individual electrons. See "Technical definition". An electron moving across a voltage difference gains energy, often measured in electron-volts.(hmmm maybe this belongs in the article) --agr 11:34, 2 December 2005 (UTC)

Clarified the reference to voltage in the fluid flow analogy: "voltage (difference in electric potential) is likened to difference in water pressure." Aboctok (talk) 08:41, 13 December 2012 (UTC)

Volt vs Voltage/Potential difference

The volt is a unit of voltage or (electric/electrical) potential difference. Right now voltage redirects to volt. I suggest that there should be a separate article on voltage, with the content split from volt. Volt is to voltage as watt is to power, newton is to force etc. The preceding unsigned comment was added by Wakiped (talk • contribs) 08:35, 15 December 2005.

Wakiped is absolutely right. Ampere and Electric current have different articles; so should Volt and Voltage. I'll add the appropriate tags. Melchoir 11:43, 15 February 2006 (UTC)

... in Volt

I was missing that in the article. That should be Tension is defined in Volts?

Huh? Melchoir 21:30, 23 February 2006 (UTC)

As: Current is defined in Amperés.

I have no idea what you're trying to say. Melchoir 07:58, 24 February 2006 (UTC)

for instance: Tesla is the standard unit of magnetic flux density. From what is Volt the standard unit? I don't know and couldn't find it in this article so I thought I should comment about it.

Oh, right. The volt is the standard unit of voltage, aka electric potential difference. Melchoir 05:37, 5 March 2006 (UTC)

Definition of Volt

I thought the definition of volt is confusing to students. Even though the statement itself is true, as a definition, it takes into account additional variables such as rate of charge flow and power. I think a much more simplified definition would be much easier for a student to grasp that doesn't take the extra into consideration. Maybe:

"One volt is the potential difference between two points in an electric circuit when the energy involved in moving one coulomb of electric charge from one point to the other is one joule." ("Introduction to Electric Circuits", Herbert W. Jackson, p. 35)

Equations for DC circuits

In the section on DC circuit equations, the following are listed:

Multiplying equations 2 and 3 produces , which contradicts with equation 1. I don't know enough physics to know if this is (somehow) right, or what would make it correct.

Ealex292 04:37, 9 April 2006 (UTC)

Split/merge/whatever to Voltage

Per Talk:Voltage and the template having been up forever, I'm performing the... operation, whatever it is. Melchoir 05:32, 9 April 2006 (UTC)

Defining a Volt

RE: This article, and those of amps, watts, etc, is very precise and I'm sure it is good reference material for engineers However as a non engineer I didn't really get anything out of this. It seems to assume knowledge of the theory of electricity and power, which I don't have.

An encyclopedic entry accomplishes nothing if it doesn't explain the subject to the common person or student, especially considering they make up the majority of viewers and should be the main beneficiaries of this site. I call on anyone reading this to post and repost the following simple explanation every time it gets deleted by poetic "engineers" who seem to care more about impressing each other with their concise definitions than helping the students and common folks that come here and just want to know what volts, amps, and watts are.

Hydraulic analogy

In the hydraulic analogy sometimes used to explain electric circuits by comparing them to water-filled pipes, voltage is likened to water pressure - it determines how fast the electrons will travel through the circuit. Current (in Amperes), in the same analogy, is a measure of the volume of water that flows past a given point, the rate of which is determined by the voltage, and the total output measured in Watts. The equation that brings all three components together is: Volts X Amperes = Watts

~~Wickimelon

Volt = Energy per Unit Charge?

Famous equation: , or watts equals current times voltage.

Simple math says , where equals time in seconds.

Another identity: , or current equals coulombs (charge) per second.

Substituting back, we get: , or watts times time (which is energy) equals volts times coulombs: . In other words: .

Thus, our units would seem to tell us that voltage is energy per unit charge, and, in fact, the electronvolt is a unit of energy equal to roughly 10-19 J. In my simple-minded layman's brain, this says to me that another way to think of voltage is as the average amount of energy carried per unit charge, i.e., the more excited the electron, the higher its voltage.

I find this view a lot easier to get my brain around than "electrostatic pressure" or some such, but, as a non-physicist, I have no idea if it is a view that makes any sense. I would appreciate comment from an actual physicist!

--Peterbstewart 18:54, 18 October 2006 (UTC)

I agree. Professor Richard A. Muller says the same thing. [2]

--Igor K 02:36, 4 September 2007 (UTC)

Absolute voltage

When talking about voltages, we usually talk about the potential difference of two potentials, for example 1.5 V in a standard AA battery. Imagine another standard AA battery with 1.5 V - how can we be sure that both battery's potentials aren't at different absolute values (that is, one battery has the potential 100 V - 101.5 V while the other has 30000 V - 30001.5 V at one of its terminals)? I hope someone understands what I mean and may give me a clever answer. --Abdull 15:24, 12 December 2006 (UTC)

This article is awful

Sorry to tell you folks, but this article is atrociously bad. Do you think definitions like

"the potential difference across a conductor when a current of one ampere dissipates one watt of power"

are of any help to somebody trying to understand electrical fundamentals or basic concepts? Please. Let's get real and get this thing edited fast. Vitamin77 05:48, 18 March 2007 (UTC)

Well, that is (apparently) its definition. The volt is just a unit, not a fundamental concept. Perhaps you're looking for Voltage? Melchoir 06:03, 18 March 2007 (UTC)

Obviously I understand that the quotation above is the formal definition of a volt, but the definition as phrased provides zero enlightenment to a person who is not already familiar with it--which should be the goal of an encyclopedia, especially one so accessible as the Wikipedia. What's needed is a definition that a normal person can understand and then build on. The meaning of terms used in the definition, like "ampere", "watt", "current", etc. needs to be grandly elucidated or this entire article needs to be re-conceptualized to make it accessible and meaningful--two things it currently is not. Vitamin77 18:37, 18 March 2007 (UTC)

Well, if you have a better definition or explanation, put it in. Melchoir 19:18, 18 March 2007 (UTC)

To kill a human

What would be the minimum amount of volts to kill a human? I am just comparing the ability of some animals and whether they would be capable to killing a person. Daily Rubbings 16:10, 12 June 2007 (UTC)

Watts would be a better unit for measuring this because watts are power flowing now while volts are how much something can flow. But nevertheless: the executions in the chair typically use an initial charge of 2000 volts for 15 seconds, but in Common Voltages it lists the things trains ride on as ~900 volts, but theoretically it only needs to disrupt the heart to be fatal, a task capable of being performed by a pacemaker. I'm going to copy your question onto the watt discuss page after this edit.

RMS or rms or Rms

I think the proper abbreviation for root-mean-square is rms not RMS. If it appear in a title where a word is to be capitalized, I think it should be Rms. Whoever is responsible for this page might want to check into that and correct it. You should be able find the definition on an IEEE website.

Before answering this comment, please note that the same point was discussed at Talk:Root mean square. It might be better to keep all the discussion on this subject in one place. --Heron 17:45, 23 June 2007 (UTC)


In the context of "Common voltages" I would rather not see RMS at all. If I was a beginner looking at a Wikipedia page, would only be concerned about whether the voltage was AC or DC. I am considering replacing all instances of RMS by AC (or would you like VAC). Gcutter (talk) 07:05, 17 September 2008 (UTC)

I agree that in the "Common voltages" section, replacing RMS by AC is appropriate. "VAC" is not a correct symbol. I'm not sure about the statement about high voltage transmission lines; a few of them are DC, and I don't know which kind has the record. --Gerry Ashton (talk) 14:23, 17 September 2008 (UTC)

fix definition of volt

I'm not a physics major (just teaching physics for the MCAT) but take issue with volt being defined as "electric potential difference" I think it should be just "electric potential" I know potential energy is always defined relative to another position and thus the differences of electrical potential initial and final are always in the units of volt but beginner students are less likely to understand the difference between volt and voltage. I would argue that voltage, a concept, is the difference in electric potential (PE = q*voltage) while the SI unit volt simply measures the potential in (J/C) at any POINT in space. It's not until you take two points (the difference) that you then get voltage and thus energy. Libertas81 (talk) 21:30, 5 September 2008 (UTC)

I would say that voltage and electric potential difference are synonyms. The unit of measure for this quantity is the volt. A different unit of electric potential difference used in the past was the abvolt, which was 100,000,000 volts. (See IEEE/ASTM standard SI 10-1997, p. 47) --Gerry Ashton (talk) 21:51, 5 September 2008 (UTC)
We agree then. voltage = electric potential difference. I'm arguing for a clearer distinction between the concept voltage and the unit volt, since "V" tends to get thrown around liberally -- which is why correct texts will use phi for electric potential. To use an analogy, the locations A and B in space each have different electric potentials and thus their own magnitude of volts. Say 20V and 10V. The volt describes the property of each space but when, and only when, you directly compare A and B do you then have a voltage. "A has an electric potential of 20 volts while B has an electric potential of 10 volts. The voltage drop from A to B, the difference in electric potentials, is 10 volts." Well, maybe this will serve as some clarification at least to those confusing V for volt and V for voltage. —Preceding unsigned comment added by Libertas81 (talkcontribs) 03:33, 6 September 2008 (UTC)
I don't have a degree in physics either; mine is in electrical engineering. I don't know about physicists, but electrical engineers just don't talk about electrical potential, they only talk about electrical potential difference (and they usually leave off the word "electrical"). You just can't say "A has an electric potential of 20 volts"; there must be a stated or implied reference point, and the potential difference from A to the reference point is 20 volts. The potential difference from B to the reference point is 10 volts. The potential difference from A to B is 10 volts. The phrases "potential difference" and "voltage" are interchangeable. Also, electrical engineers usually use the variables E or V for voltage. Variables should be in italics whenever the typographical system in use allows. --Gerry Ashton (talk) 03:47, 6 September 2008 (UTC)
Looking through the article, I see there are no variables. In every single instance, the V is the symbol for the unit volt. There would be no opportunity to use Φ (or was it φ) even if you were inclined to. (My undergraduate physics book, Halliday and Resnick, used V for electrical potential and electrical potential difference. --Gerry Ashton (talk) 03:59, 6 September 2008 (UTC)
Thanks for your input. While I will still differentiate phi and V for technical clarity I'll concede that physicists, engineers, et. al don't bother making the distinction since, as we both note, electric potential is a meaningless concept by itself. It is the difference between two electric potentials that gives rise to energy. Thanks. Libertas81 (talk) 02:20, 7 September 2008 (UTC)

C-cell image caption

Those aren't "batteries", they are single cells. The standard 9 volt things are actual batteries, as are the things we use to start our cars. I guess I should just fix the caption... Huw Powell (talk) 22:21, 31 January 2009 (UTC)

Clarifications - April 2009

I have made some tidy-ups in the article, to make a clearer distinction between the concepts of "voltage" and "electric (i.e. electrostatic) potential". In doing so, I have removed the "Radio Shack" reference, on the grounds that it is 30 years old and superfluous - as we already have a direct link to the most up-to-date official international reference source to SI units. (RGForbes (talk) 18:03, 14 April 2009 (UTC))(Richard)

Volt in terms of SI base units

Under the definition, it writes that the volt "can be written in terms of SI base units as: m2 · kg · s-2 · C-1." This is not correct, because the Coulomb is not a SI base unit.

Instead, the second last derivation of the volt is correct (kg · m2 · A-1 · s-3) —Preceding unsigned comment added by 202.156.9.244 (talk) 13:27, 7 May 2009 (UTC)

Aircraft power uncited, wrong

The article currently mentions 400 V AC aircraft power. This is probably wrong. 400HZ AC power is commonly used on aircraft, but the usual voltage is 120V, or three-phase, four wire 120/200V wye. Several DC voltages are also used, but 400V, no. That's way too high. --John Nagle (talk) 21:40, 20 February 2010 (UTC)

Volt: to capitalize or not to capitalize

The SI usage rules on the NIST website say that units based on proper names (of people!) should be capitalized. They give the example of "Celcius." See section 6 under 6.1.2, also 5.2 But "volt" is not "Volta." —Preceding unsigned comment added by 128.95.172.173 (talk) 02:46, 29 October 2010 (UTC)

First of all, the unit is degree Celsius, and it begins with a lowercase letter, "d". Second, only symbols are capitalized if the unit is named after a person, that is why the symbol for the unit of electrical potential is "V" rather than "v". Finally, when the unit is spelled out, it always begins with a lower-case letter: "volt". Jc3s5h (talk) 03:04, 29 October 2010 (UTC)

tidy up

the definition should be removed & moved (mostly) into the intro paragraph. Also, that information needs to be made more understandable. Specifically, the 'conductive wire' that is used to measure voltage is typically connected to a voltmeter which then probes a circuit (not a conductor). You can only get volts from a working circuit,otherwise there aren't any volts... there is just a lot of jumbled up info that doesn't really focus on the fundamental aspects... Also, the intro needs to be edited to focus more on the volt and not the achievements of its namesake. ~redundancyredundancyredundancyredundancy — Preceding unsigned comment added by Lawstubes (talkcontribs) 18:22, 5 October 2011 (UTC)