Talk:Electric potential

message: Electrical potential is different from Electrical Potential Energy, but this definition doesn't tell the reader that.  This is a common misconception, and I think that it would be very useful if the distinction was made clear here.f
Electrical potential is the potential energy per unit charge seems OK, please explain.--Patrick 10:55, 31 May 2004 (UTC)

message: Any reason why the color gradient is the OPPOSITE of the energy gradient - shouldn't the highest potential (highest energy per unit charge) also have the highest energy visible spectrum color (shortest waves eg violet) and the lowest potential have the lowest energy color ( long waves hence red)? 2A02:ED0:6D8E:DC00:1B8:C489:EFA7:28BA (talk) 08:42, 29 December 2020 (UTC)
thread_title:  Potential diagram 

message: Since voltage is by definition a "potential difference", a potential must be able to be measured with no reference.  How is this done?
Is it correct to think of a potential as "the voltage relative to infinity"?  I mean infinite distance. - Omegatron 21:26, May 30, 2005 (UTC)
Similar question:  If I have a piece of metal with one less electrons than protons (or a single atom with one less electron than protons), that object has a definite charge of +1, correct?   The object's charge is an absolute quantity.  Does that object have an absolute potential?  Or does potential always involve a reference value? - Omegatron 00:17, May 31, 2005 (UTC)
:You're trying to use a specific form of a concept (voltage) to shed light on a general form (potential).  That's a foolish approach, if you ask me.
:Yes, potential always requires a reference point.  As the article says, potential is defined as a line integral over an open path.  An open path must start somewhere, so there you have it. --Smack (talk) 04:28, 2 Jun 2005 (UTC)
thread_title:  Voltage and potential 

message: I teach technicians electronics and all the mathematical mumbo jumbo does not help them to obtain an understanding of the difference between emf, voltage drop & potential difference.
I teach that an "emf" is a source of electical energy which can motivate electrons around a circuit. Ie. it has to be an energy source of some sort either a battery or a power supply, a charged capacitor, the voltage produced accross an inductor when there is a changing magnetic field, a illuminated solar cell  etc.  Disconnect it and electrons stop moving and the circuit does not go.  In a purely resistive circuit the current is always phase with the voltage
A "voltage drop" on the other hand is the voltage difference accross a load when a "current flows" through it.  The current and voltage in a purely resistive the current and voltage are always 180 degrees out of phase.
A "voltage or potential difference" is the difference in voltage between any two points in a circuit, which could be an emf, a voltage drop because of a current or could include the voltage accross an "open circuit", through which no current flows at all"
Ie. In a wheatstone bridge, an "emf" is applied accross two arms each arm comprising of two   resistors. A current flows through each arm producing voltage drops in each of the four resistors.  A voltage difference, exists accross the open circuit between the centre points of the two arms (dependent on the balance in the bridge of course) whilst the current is 0.
As a result I use E in ohms law where I calculate the current from a power source and V where I calculate a voltage drop.
Lee de
Hi Lee, as a professional electical engineer it seems to me that the distinctions you make are entirely false and misconceived.  There is absolutely no qualitative difference between a 'voltage drop', a 'voltage or potential difference' and an 'emf', and to suggest to your students that there is any difference is to mislead them completely. The fact that a voltmenter responds identically to these quantities should alert you to the possibility that they are precicely the same kind of thing.  The effect that these quantities have on an electric charge (such as an electron) is also qualitatively identical; in a typical oscilloscope circuit, the electrodes of the cathode ray tube are usually connected to different points in a resistive potential-divider , and the so-say 'pd' has exactly the same effect on the electrons in the tube as a source of 'emf' would have.  Perhaps the distinction that you are striving towards is that between a component which acts as an energy source (such as a voltaic cell, a charged capacitor, an inductor carrying a current, etc) and one which acts as a dissipator of energy such as a resistor.  But even here you should be aware that components which act as sources of 'emf' (and of energy) can very easily become energy sinks with 'pd' simply by reversing the direction of the current.  In an AC circuit a capacitor or inductor makes this change every cycle, and can do so in a DC circuit as well, depending on whether the component is being 'charged' or 'discharged'.  From the point of view of circuit analysis the only useful distinction is that between components in which (at a particular instant) the current opposes the pd (energy being stored or dissipated in the device), and those in which the current is in the same direction as the pd (energy being delivered by the device). This distinction must be observed when drawing up the equations used in dc circuit analysis.  Notice that this distinction is between electrical components, not between supposedly different types of voltage, which is an absurd notion.  Andrew Smith  — Preceding unsigned comment added by 82.32.48.177 (talk) 12:56, 14 December 2011 (UTC)
thread_title:  emf - voltage drop - voltage difference - potential difference. 

message: when we connect a charged conducting sphere to the ground , what happened to the charge on the surface since the electric potential (v) on it is zero"??? —The preceding unsigned comment was added by 213.209.187.34 (talk) 02:25, 17 December 2006 (UTC)
thread_title:  when we connect a charged sphere to the ground 

message: So is it a vector? The article doesn't seem to be too explicit about it.160.227.129.254 23:07, 1 May 2007 (UTC)
replies: text: The usual concept of electric potential is a scalar.  It generalizes to a four-vector when you consider the effects of moving charges and relativity; one of the four dimensions is the scalar electric potential, and the other three are the vector (magnetic) potential. Dicklyon 05:14, 2 May 2007 (UTC)

text: It's in the article.  If it's not clear enough, work on it. Dicklyon 00:19, 3 May 2007 (UTC)
thread_title:  Vector? 

message: Electric potential is measured in volts, while electrostatic potential [energy] is measured in joules. Why does the article say they're the same thing? Lecture 4 explains the difference (MIT OpenCourseWare). —Pengo 07:35, 31 August 2007 (UTC)
thread_title:  Electric potential vs electrostatic potential 

message: I have thought for a while that the electromagnetism template is too long.  I feel it gives a better overview of the subject if all of the main topics can be seen together.  I created a new template and gave an explanation on the old template talk page, however I don't think many people are watching that page.
I have modified this article to demonstrate the new template and I would appreciate people's thoughts on it: constructive criticism, arguments for or against the change, suggestions for different layouts, etc.
To see an example of a similar template style, check out Template:Thermodynamic_equations.  This example expands the sublist associated with the main topic article currently being viewed, then has a separate template for each main topic once you are viewing articles within that topic.  My personal preference (at least for electromagnetism) would be to remain with just one template and expand the main topic sublist for all articles associated with that topic.--DJIndica 16:36, 6 November 2007 (UTC)
thread_title:  [[Template:Electromagnetism]] vs [[Template:Electromagnetism2]] 

message: The electric potential is not a lorentz scalar, it is compontent of the 4-vector  A_\mu . Adiel lo (talk) 07:39, 26 May 2008 (UTC)
thread_title:  lorentz scalar 

message: It has been known to research scientists in some branches of science, for about 60 years, that "voltage" and "electric potential" are slightly different concepts. However, this doesn't seem to have made it into some physics textbooks yet, and there is lot of confusion on this issue around. I hope no-one is going to mind, but I have removed from this article all technically inappropriate references to voltage, so that this article really does become an article on electric potential (sometimes called electrostatic potential).  At the time of writing, there is a modern electron-based definition of "voltage difference" in the article on "voltage".  (You can start by defining "voltage difference" to be what you measure with a voltmeter, and then ask what scientific quantity it is that you are actually measuring. Quite often it is NOT electric potential difference.)  At the time of writing, there is fuller discussion of the issues in the articles on "electrochemical potential" and "Fermi level", and related links and discussion pages..
I have also removed the equations that were formulated in one of the cgs systems of equations.  There was international agreement nearly 40 years ago to gradually discontinue these systems of equations, and to concentrate on the single system now used for teaching in most universities. Most current students (and, I suspect, many lecturers) do not understand that there are several possible systems of equations, and most people do not need to understand anything other than the system currently used [i.e., the (rationalized) metre-kilogramme-second-ampere system that forms the basis for SI units]. If you are one of the few that do, then you will find it easier to look this up in a well-written article elsewhere.  In my experience, nowadays it simply generates confusion if we try to explain basic concepts using a near-obsolete and disused  equation system. (RGForbes (talk) 19:52, 10 April 2009 (UTC)
thread_title: "Voltage" and "electric potential" are different concepts (& we don't need cgs equations here)

message: 'Electric potential difference' redirects here, but nowhere in this article does the words 'electric potential difference' occur.  —Preceding unsigned comment added by Loldrup2 (talk • contribs) 21:44, 25 May 2009 (UTC)
thread_title: electric potential difference

message: Nabla A-vec(r-vec,t)=-mu*J-vec(r-vec,t)
sry, dont know how to write this properly. A-vec and the rest indicates a vector. mu = permeability of vacuum. Maybe we should ad this as well as a definition of electric potential.  —Preceding unsigned comment added by 134.184.101.26 (talk) 20:22, 5 October 2010 (UTC)
thread_title:  Vector potential of Newton 

message: I find the animations are so confusing as to be completely useless. I just have no idea what's going on. It doesn't help that the text and equations are mostly unreadable, and that the captions contain no further explanation. But even if those could be fixed, the bigger problem is, they seem to be videos captured directly from applets, constructed to be played with rather than constructed to clearly visually explain an otherwise-confusing pedagogical point. Therefore I propose deleting all three animations (see now-current version of the article). What do other people think? --Steve (talk) 13:59, 9 August 2011 (UTC)
replies: text: These animations have multiple issues that need to be resolved.  Unless the issues are resolved, they should be removed.--LaoChen (talk)00:54, 11 August 2011 (UTC)
thread_title:  Propose deleting animations 

message: It seems that the electric potential is "the amount of electric potential energy" per unit charge but only for an infinitesimal charge. Often if I place a finite charge Q in some location, then the charges in nearby materials (dielectrics, conductors, etc.) will reconfigure and the electric potential will change, in a way that depends on the amount Q. In those cases the change in electric potential energy is not strictly linear in Q. I'm referring here to image charge potentials and such related things. It could be clarified by saying:
* placing a unitary charge but without moving any other charges, i.e., placing the unitary charge in that location only for an instant, or
* electric potential energy per unit charge, for an infinitesimal charge.
--Nanite (talk) 07:18, 17 July 2013 (UTC)
replies: text: Did you make the change?  And someone reverted it?  To not be OR, need references.  You're exactly right, Potential is not the work done, instead Potential the energy/charge ratio of locations in a field when no charges are present (or, when an infinitesimal test-charge is used.)  Similarly, the electric vector-field is not a force, instead it's the force per charge, for an infinitesimal test-charge.  (Besides being more rigorously accurate, if we change the wording then we don't accidentally reinforce the widespread misconception that "Potential" is really just Potential Energy.) 71.217.40.134 (talk) 19:25, 21 September 2017 (UTC)
thread_title:  Finite vs. infinitesimal charges 

message: The Introduction section briefly talks about the concepts of forces and potential energy, and then there is this sentence: "As an object moves in the direction in which the force accelerates it its potential energy decreases". 
This makes it sound like any force acting on an object will reduce its potential energy, which is wrong. If I pick up an apple, I accelerate it upwards and simultaneously increase its potential energy. Maybe "the force" in this case only refers to the force generated by the field that gives the object its potential energy, but that's not made clear, and it is probably too confusing for what's supposed to be a simple analogy. Seban678 (talk) 09:22, 28 April 2015 (UTC)
thread_title:  Error in the Introduction? (Classical mechanics analogy) 

message: Please note the earlier discussion of this article at Wikipedia talk:WikiProject Electrical engineering#Three articles, two concepts Oiyarbepsy (talk) 04:09, 21 May 2015 (UTC)
thread_title:  Discussion about this article 

message: What type of movement of electric charges, used for defining the electrostatic field and its circulation, can occur in an electrostatic potential, where charges are supposed not to move?--82.137.13.51 (talk) 19:16, 22 October 2018 (UTC)
thread_title:  Movement of electric charges in an electrostatic potential 

message: On section "Generalization to electrodynamics" of this article it says "When time-varying magnetic fields are present (which is true whenever there are time-varying electric fields and vice versa)". It says that if there are time-varying electric fields, then there are time-varying magnetic fields.
But as far as I know, that's not necessarily true. For example, in magnetostatics there are static magnetic fields but time-varying electric fields (because there are currents, but they're steady/DC not AC).
This mistake should be fixed. Alej27 (talk) 12:31, 6 January 2021 (UTC)
thread_title:  There can be static magnetic fields with time-varying electrics fields 

message: what is \mathbf{r}' in this equation in section "Electric potential due to a point charge"
: V_\mathbf{E}(\mathbf{r}) = \frac{1}{4 \pi \varepsilon_0} \int \frac{\rho(\mathbf{r}')}{|\mathbf{r}-\mathbf{r}'|} d^3 r'. 
I think it would be good to make that clear to readers, it is not clear to me for example. 15:00, 21 June 2021 (UTC)
replies: text: r is position.  The potential at point r depends on the charge density at each point r' at which the charge density is not zero.  The expression is integrated over a volume of space that contains all the points r' at which the charge density is not zero.  If the charge at point r' is a discrete charge rather than a density, then ρ is a type of Dirac impulse.  If r is a point inside the volume of integration, you get a divide by zero problem when r = r'.  If ρ is a density, the limits work out, but if ρ is a discrete charge, the result is infinite.  Constant314 (talk) 14:06, 21 June 2021 (UTC)

text: I have added some definitions to the article.  I hope it helps. Constant314 (talk) 15:15, 21 June 2021 (UTC)
thread_title:  what is \mathbf{r}' denoting? 

message: The description emphasizes electric field lines (lines perpendicular to the balls), but shouldn't the lines of constant electrical potential (the equipotential lines perpendicular to the field lines) be mentioned as well, considering that's the topic of the article? BennyWahWah (talk) 20:32, 12 October 2022 (UTC)
thread_title:  First diagram description