Questions tagged [voltage]

Voltage is the unit of measurement for electronic potential, from one point location to another.

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Sign conventions for the electric potential, the tension and the current [closed]

In the sketch below, the black stuff was given. I was wondering how the sign conventions are. My approch was like this: I called the upper point A and the lower one B I made an arrow for the tension ...
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Phenomenon causing Voltage in Batteries

I have a simple question: you can think of a charged particle as a particle with mass, and hence there will be an electric field surrounding the charge, which causes electric potential energy (if ...
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Kirchoff Law, Loop [closed]

[![look up for the value of Vx and Vo][1]][1] [1]: just please help me with this question cause it should be submitted tommorow, thankyou <3
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Discharge of a capacitor with variable backvoltage?

I understand that the voltage of a capacitor as it discharges overtime is $$V(t)=V_0e^(-t/RC).$$ I've also heard people say things like "voltage is relative. The voltage to the ground or the ...
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Electricity: Ohm law vs Power in the Water analogy

I'm trying to understand electricity principles with the water analogy. I know this analogy is not perfect, but so far it has helped me the most. To recap: voltage (volt) is like water pressure ...
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High voltage in transmission wires [duplicate]

My teacher asked a question and said to search about it. We know that the power consumption of the resistance (wasted power) can be obtained by the following formula: $$\begin{align} P &= I^2R \\ ...
BaRiboD's user avatar
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Purpose of potential difference in the presence of an electric field

Based on my understanding, charges are pushed along wires due to an electric field created by the battery, and charges gain electric energy as they loop through the battery. But I can't seem to ...
AscenderVI's user avatar
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Would it be right to say that “Electric Potential” = the potential energy of an individual unit of charge at a certain point in a electric field?

Any replies from people who actually understand the topic (better than me, to say the least lol) and are able to clarify the topic (unlike my teacher), are highly appreciated and encouraged.
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What is the difference between: “Electric Potential”, “Electric Potential Energy”, “Electric Potential Difference”, and lastly, “Voltage”? [duplicate]

Please provide very simple and specific examples/explanations when answering. Some have described Electric Potential as “work done per unit of charge”, but what exactly does “per unit of charge” mean? ...
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Why does current increase in step-down transformer?

I'm trying to make sense of transformers. $\varepsilon_{p} = $ emf in primary coil, $\varepsilon_{s} = $ induced emf in secondary coil, $N_{p} = $ number of turns in primary coil, $N_{s} = $ number of ...
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Is power of a battery constant?

In my question I'm neglecting the impact of discharging. I'm trying to make sense of Watt's law: $$P=IV.$$ I always thought that the voltage and the power of a battery were constant features that ...
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When forming an n channel in an N mosfet, do the pn junctions of the drain-substrate and source-substrate parts disappear?

When forming an n channel in an N mosfet, do the pn junctions of the drain-substrate and source-substrate parts disappear? Here's what I expected: When gate voltage (higher than threshold voltage) ...
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I find two different answers using Kirchoff's rules on single loop [closed]

I found this question in a book asking for voltage $X$. I allowed them to use any method they want. I too after revision using kirchoff's loop rules am getting too different answers. Please help me to ...
KANYARWANDA Cyprien's user avatar
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2 answers
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What is the "closed circuit" of a bug swatter racket?

There are bug swatter racket that can kill fruit flies, mosquitos, or flies, if the insect touches the metal mesh. However, when I look at the construction of the device, the metal mesh is all one ...
Stefanie Gauss's user avatar
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Why is the electric field the strongest inside the resistors?

My understanding is that current is constant throughout the circuit. So it means that in the areas with high resistivity or small cross-sectional area the drift speed on electrons is the highest. ...
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Why is potential difference across resistor different than potential difference across a wire?

As far as I understand, the electric potential is the amount of energy that a third party agent has to spend to move a positive charge from infinite separation to a point. Thus, the electric potential ...
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Confusion about Circuits

I have two questions: When dealing with simple DC circuits, it is often said that the electrons in the wire move because the charge density of the surface charges decreases. Is that due to the fact ...
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Voltage across the diode?

Why the voltage across an ideal pn junction diode remains 0.7 volts, even when the applied voltage exceeds 0.7 volts? Shouldn't it be the applied voltage minus the 0.7 V?
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Definition of voltage for motional EMF

In the schoolbook physics example of a generator, the wire loop rotating in a constant (both in space and time) magnetic field, we can measure a non-zero voltage between the loop's two terminals due ...
Damian Birchler's user avatar
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What is the electric potential difference for two spheres capacitors connected in series [closed]

Consider two spherical capacitors with Identical radii for the inner and outer spheres (let them be a and b). +q and -q charges are in the inner and outer sphere on Both the capacitors. Now I connect ...
Al-Ahsan Abhro's user avatar
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4 answers
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Electric Potential and Potential Energy

Electric Potential definition is as follows: Electric potential (also called the electric field potential, potential drop, the electrostatic potential) is defined as the amount of work energy needed ...
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3 answers
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Birds on power lines two feet versus one

So I know a bird can stand on a power line without being electrocuted because there is no current going to the ground. However, I know that curents will pass to different electric potentials. My ...
Mikayla 's user avatar
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4 answers
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Proportionality: $I ∝ V$ or $V ∝ I $, are both of them correct?

I have a simple question that's been on my mind for a while. If both current is proportional to voltage ($I \propto V$) and voltage is proportional to current ($V \propto I$), are they actually saying ...
Peter swift's user avatar
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1 answer
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How to deal with the current going opposite direction through battery [closed]

Say that the current source is doing whatever it needs to do to output $1$A and that the battery is a $3$V battery. For simplicity, say the resistor is $1\Omega$. I get that since we have $1$A ...
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How to typeset "$\rm kVp$" (kilovolt-peak) in CT physics?

I'm not a radiation physicist. Kilovolt-peak appears to be used as a unit, with descriptions such as "80 kVp". Should this be typeset as a single unit written "Vp", similar to e.g. ...
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Basics of Capacitor

Looking at the formula $C = \frac{Q}{U}$ does a high capacitance mean that with a low voltage we can bring more charge onto the capacitor? How is total charge on the capacitor linked with voltage?
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Constant Voltage In a parallel circuit

We know that in a parallel circuit the voltage in each resistor is the same, but that doesn't make sense at all, I mean lets consider a circuit with a parallel resistance r1 and r2. V = IR is applied ...
gsdvgsdfgsf's user avatar
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Energy lost in a resistor and its temperature

The power lost across a resistor is proportional to the square of the voltage drop across it. This means by increasing the voltage across the resistor, the energy lost in it in a given time grows non-...
seyyed mohammad saadatmand's user avatar
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What determines the relevant surface area of the electrical conduction?

I'm using a four-probe system (nextron) to measure the voltage between the two points of my sample. Sample has a cylindrical shape and it's placed on its base inside the instrument. The probes are ...
Dario Mirić's user avatar
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Concept of Surface (Sheet) Resistance

On the page 2 of the article about the surface resistance (link given below), the following is stated: It is assumed that electric current flows on the surface of the material only. https://www....
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Before and after current passes through a resistor is the potential considered to be constant in the conducting wire? What about V due to battery? [duplicate]

(This is not a duplicate. I am asking this because I am confused with the potential difference provided by battery and the effect of R(resistance) in in determining the potential difference). Recently ...
john9's user avatar
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How do changes in a video file during editing relate to voltage levels?

I’m trying to understand the relationship between video editing and voltage levels. For instance, if I trim the first 10 seconds of an MP4 video file or add an audio track, how are these changes ...
Madden Crush's user avatar
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1 answer
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Power delivered to a Resistor is $V^2/R$. Does size of battery matter?

I had connected a thin Resistor wire to series combination of six coin cells or to a small sized 9V battery. The wire got hot in a normal way BUT when I connected the same resistance wire to a large ...
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Why is the potential due to induced charges constant?

Over the past few days, I have taken the time to read this interesting paper, where an unexpected counterexample is given that shows how the electrostatic force between a neutral metal conductor and a ...
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Method of image charges for electric potential in a metallic disk

It is well known that the method of image charges is not always applicable, so I was wondering: is there an analytic way to calculate the electric potential for a point charge interacting with a ...
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Do electrons build up at the entrance of a resistor? [duplicate]

There is a voltage drop between the start and end point of a resistor. How does it achieve this difference in potential? For there to be a difference in potential there must be difference in charges. ...
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Understanding surface charges on a resistor and what a voltmeter is measuring

In this video Veritasium points out some misconceptions about electricty and hints at surface charges generating the actual electric field within the wires, better explained by Professor Carlson here. ...
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How would voltage change in time in an electrolytic solution?

I'm building a teaching model and a question came up that isn't very clear to me. I would like some help. The voltage of a sphere (~5 cm in diameter) uniformly charged, in this case positively as in ...
Vander's user avatar
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3 answers
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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 ...
potato's user avatar
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2 answers
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Decreasing of a charge amount and its effects on a capacitor

There is an equation of charge amount on a capacitor you may know; This graph above shows the charge amount. And according to the book "Fundamentals of Electric Circuit from CK Alexander", ...
Nafi Can Ereli's user avatar
8 votes
3 answers
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How do charge carriers "know" how much voltage to use for work in a specific component? [duplicate]

I understand the basic concepts of voltage pretty well, I think. However, one thing has been bugging me which I can’t seem to figure out. How does a specific charge carrier "know" how much ...
Basil's user avatar
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Why is there no negative sign in the linear form calculation of voltage but there is a negative in the integral form? [closed]

The formula for voltage given $\vec{E}$ and $d$ is $$V = |\vec{E}| d.\tag{1}$$ However, the formula is also $$V = - \int \vec{E} \cdot dr. \tag{2}$$ Why does one of these formulas have a negative and ...
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Solution to Laplace equation in spherical coordinates and Legendre polyomials

I have the following problem: A metallic sphere of radius $R$ is placed in a region where there is an electric field $\vec{E} = E_0 \vec{e_z}$. Solve Laplace equation for the scalar potential $V(r, \...
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Voltage Difference Across Capacitor Plates

If a parallel plate capacitor is connected to a 9V battery, what is the electric potential difference between the two plates? Is it 18V since the positive plate will have an electric potential of 9V ...
Benjamin Goldstein's user avatar
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What is the equation describing the boundary of a 2D charge density?

Consider a charge density $\rho(x,y)$ distributed on the 2D plane. The charge density follows the Poisson equation: $$\nabla^2 \mathbf{\phi}=\mathbf{ \nabla\cdot E}=-4\pi\rho(x,y),$$ where $\phi(x,y)$ ...
Matt's user avatar
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Instantaneous Voltage of Generator / Radian / Angular Frequency Question Lack of Understanding

I'm training to be an electrician and am struggling to understand this formula any help would be appreciated. The formula is $V_s = V_0\sin(\omega t)$ I believe this is the formula for instantaneous ...
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Fowler-Nordheim tunneling following high voltage and voltage breakdowns in X-ray tubes

I am taking some measurements concerning a vacuum based X-ray tube. One has to ramp up the voltage slowly in a process called conditioning of the tube. Without allowing a current to flow along the ...
user996159's user avatar
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Does an electric field induce current in a floating ideal capacitor?

The company "Fluke" makes a DMM that they claim can measure AC voltage by simply clamping the connector around a live wire, and using the E-field to induce a voltage/current into the ...
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Help With Complex Numbers in Polar Form in the Context of AC Voltages

I'm learning about AC right now, and I think I've got an OK grasp of complex numbers (not in their polar form, though), but I don't understand this step in a derivation at all: $$V_i=V_0e^{j\omega t}$$...
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Why electric potential can be evaluated by conservative electric field?

The definition of electric field is following: The electric field is defined at each point in space as the force per unit charge that would be experienced by a vanishingly small positive test charge ...
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