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

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Continuing on voltage drop across a resistor [closed]

What exact wire diameter allows approximately $6.25\cdot 10^{18}$ electrons to pass in 1 second? Will a thinner diameter or a wider diameter wire allow the same approximate number of electrons in a ...
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$P=VI$ and $P=V^2/R$ [duplicate]

How come equation a) $P=VI$ says if you double voltage, power is doubled while according to equation b) $P=V^2/R$ says power quadruples? Which one is correct?
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Proving an AC current with peak amplitude of 311V is equivalent to a DC current of 220V [closed]

If one starts with an alternating current in the form of a sin wave with a peak amplitude of 311V and then goes through the usual RMS procedure of integrating $sin^2$ from 0 to 2$\pi$ then the result ...
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68 views

Why do we say that there is a voltage drop only when charge passes through a resistor? [closed]

This is a little confusing for me. I will just ask a few questions: First: Am I correct in saying that while traversing through the circuit, charge looses some electric potential(not energy) at ...
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Doesn't any massive conductor look like “ground” to an AC supply?

I've been puzzling over this excellent answer to the perennial "Why don't I get shocked by a hot wire if I'm not grounded?" question. The orders of magnitude just don't seem right for two reasons: ...
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58 views

Short circuit in superposition

I'm really confused about the concept of short circuits. I don't understand, why when you short those two voltage sources, 20 and 10 ohm resistors become parallel? What happens with 4, 12, 15 ohm ...
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62 views

Transformer do not work in DC (50Hz) digital signal? [closed]

condition 1: By passing DC current through copper coil it generate the magnetic field. condition 2: By moving magnet around cooper wire it generate current. When DC current of 50Hz passes through ...
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34 views

Voltage across a resistors

When i was doing the practice problems, I found the following problem: I was able to solve for everything except for V4. When I looked at the solution manual,solution was as follows: Use KVL: V4 = ...
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Data acquisition from Pins ( 5Volt) [closed]

I'm trying to creat a data acquisition system using: computer Geosig ve-53 KPci3101 from the seismic sensor's manual we can see that every pin's output is a 5 volt (or 10?), my question is, how ...
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57 views

Solving for node voltages

I have the following circuit and i need to solve Is, v1 and v2. First of all, I assumed that this problem will involve supernode principle since there is a voltage source between V1 and V2. Then, i ...
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64 views

Touching one end of a battery

What happens when I touch one end of a battery? Is there any flow of charge from the battery to my body? I know that connecting a battery to both ends of capacitor causes the charge from one plate ...
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99 views

How is a variable potential divider able to reduce current/voltage through a component to zero, unlike a variable resistor?

For example, the diagram in my text book shows a filament lamp, in series with a uniform resistive wire, which can have its voltage and current varied by moving the sliding contact, e.g., a ...
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Why is resistance $U/I$ rather than $I/U$?

What is the difference between resistance and conductance and why is resistance $U/I$ and not $I/U$? (I know $I/U$ is conductance.) But I don't see the difference between both.
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43 views

Why does a variable potential divider have the ability to reduce current through a component to zero

For example, the diagram in my text book: shows a filament lamp, in series with a uniform resistive wire, which can have its voltage and current varied by moving the sliding contact, e.g., a ...
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2answers
81 views

Accelerating potential

Will an accelerating potential accelerate a neutral atom? For example, consider an atom of hydrogen subjected to an accelerating potential of $V$. As the kinetic energy of a particle accelerated by a ...
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85 views

How is a potential divider able to reduce current to zero?

For example, a filament lamp, in series with a uniform resistive wire, can have its voltage varied by moving the sliding contact, e.g., a rotatable wheel. However, why is a potential divider able to ...
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16 views

How to calculate ion lithium battery voltage?

I have raw data from cyclic voltammetry test of ion-lithium battery. But I need nominal voltage or Open Circuit Voltge (OCV), like is reported in the literature. But I only have Voltage (V) vs ...
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79 views

What exactly is potential difference? What are the factors that effect it?

I am asking this question because at first I thought that this concept was pretty clear to me, but it is not. So, my first question: Is potential difference only a property of an electric field? If ...
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44 views

$P=V^2/R$ confusion

I am confused on how to apply the formula $P=\frac{V^2}{R}$ If I am given a bulb say with power 60W and it is connected to a supply of 120V. Then the resistance of the bulb is 240$\Omega$ but if ...
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140 views

Transformers: relation between their current, voltage and resistance

My current understanding Transformers are used to step up and down voltage keeping power constant. Hence, for example, if I step up some voltage, the current will decrease in the secondary circuit. ...
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36 views

How to control a dc motor? [closed]

I am in 8th standard and I am doing a project on 3d printing pens. I want to know how to control a dc motor, so that when I press a button it should increase its speed gradually till it reaches its ...
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136 views

Understanding parallel plate capacitors [closed]

I need help with understanding this assignment. I originally though of using the equation of Eo*A/D = Q/ΔV but I don't know how to answer this without actual numbers to plug in besides the epsilon-not ...
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Voltage wave reflections in transmission line loaded by matched resistor

Suppose I have a power source, a transmission line and a resistive load all connected together and all sharing the same impedance. If I send a voltage pulse starting at the power source, traveling ...
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Determining initial voltage across a capacitor [closed]

This one has got me stumped. I have a graph of voltage vs time and a corresponding power vs time graph. Taking the integral of the power vs time graph gives me the work done on the capacitor. Now the ...
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1answer
17 views

Build a device that can set voltage according to intensity of the light shined [closed]

I want to build a device that uses photodiodes and photoresistors to set the voltage in the circuit that shines a bulb. The idea is simple. When the light is intense, the bulb should shine less, when ...
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Charging by induction [closed]

When we charge an conductor by induction and grounding, we first bring a negative charge to the conductor. As a result the mobile electrons of the conductor get repelled and stay far from the negative ...
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What changes in the electrons before and after a voltage drop?

It is easy to visualize gravitational potential energy as a function of the position of height, and a change in this potential is manifested in a change in height. Further, by the work-energy theorem ...
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Potential difference across a resistor

I would like to know if the potential difference between the two ends of the resistance is same as the potential difference between any tow points in the resistance whose length is smaller than the ...
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93 views

Kirchoff's rules and inductance

Can Kirchoff's loop rule be applied in a scenario involving an inductor? Kirchoff's loop rule states that the closed loop integral of E dot dl is equal to zero. But, in a situation with an inductor, a ...
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50 views

Electric field along a wire and load

I have referred to many books and all of them apply loss in potential across a resistor only in case of circuits. However, the electric field is present in the whole conductor. Hence the electrons ...
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127 views

Why is current shared in a parallel circuit but not a series circuit?

Electricity test coming up. It's not clear to me why current is shared in a parallel circuit but not a series circuit.
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64 views

Applying Kirchoff voltage law to a short circuit

If you consider an ideal wire with no resistance that shorts an ideal battery, the only voltage drop that exists is the emf of the battery, with nothing to balance it. Obviously in the real world ...
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How polarized object's polarized atoms behaves like charge?

Electrical polarization is just the shifting of the constituent atoms' protons and electrons in opposite directions. This creates a bound charge, and this bound charge creates voltage and thus an ...
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Modeling the working of a transformer by pushing magnet into a coil

Let me go step-by-step. First I will outline a simple transformer. There are two circuits next to each other (not touching). One is an electromagnet set-up (with AC supply) and the other has a ...
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Is the electric field in the wires of the parallel circuit always the same and how that affects current?

When we connect two resistors connected in parallel with a battery, it creates an electric field through this wire. well, my question here: Is the electric field in the main wire is the same as the ...
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Voltage and Current

I know that as voltage increases, current increases by $V=IR$, but I really find some difficulty in understanding this at the atomic level (what happens with the electrons inside that wire). I ...
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Current through resistors crossing each other [closed]

Calculate the current shown by the ammeter A in the given circuit. I've searched the internet but didn't know how to search for it. Please help
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Which light bulb will burn out? [closed]

We have 5 light bulbs connected in series assuming all bulbs have identical characteristics. The environment is identical for all bulbs. Wire is superconductor (0 Ohm) and is thick enough to deliver ...
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Voltage and Current in an Electromagnet

I'm having a little bit of trouble with electromagnets. I know that a magnetic field is induced by current flowing through a conductor, but what role does voltage play? Does it have an effect on the ...
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What were the experiments performed that lead to ohm's Law

How was the relationship of $V=IR$ first developed? What were the experiments that were preformed that lead to Ohm's Law? I understand that they had devices during George Ohm's time to measure current ...
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Fréedericksz transition question

What is the lowest voltage needed for a Fréedericksz transition to occur?
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High voltage arc stability reasons (in some cases shape of the arc is rapidly changing)

When turning off 500kV switch we can see an arc like on this picture this arc is very unstable, curved, distorted. It consists of many little loops. While on this picture electric arc patiently goes ...
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How to draw + and - and $\nabla \times E$ on a circular wire?

Faraday's Law: $$\vec{\nabla}\times\vec{E}=-\frac{\partial\vec{B}}{\partial t}$$ Circulation of electric field: For time-varying magnetic field and a closed wire, How can we add + and - pole ...
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130 views

How could a current passing through a resistance create a voltage as predicted by Ohm's Law?

I have a question about the classic relation $V = RI.$ I know that is the voltage that creates the electrostatic force. But I do not understand how, in a circuit with just a current source and a ...
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36 views

Induced EMF dependent on terminal wire connection?

Figure(a): When a conductor moving inside magnetic field, of a given length at a certain velocity the induced EMF is: $$\epsilon = vBL$$ However, what if we changed the position where the bottom ...
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1answer
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How to calculate resistivity of ring [closed]

Q: In a resistance experiment, a gold ring was connected into a circuit as a resistor. The connections touched on diametrically opposite points on the circular ring. Its diameter is 2cm, and the ...
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1answer
58 views

Voltage and Energy in a capacitor [duplicate]

Well, my first question is related to the energy of the capacitor. Why does the energy of capacitor equals $E=\frac{1}{2}QV$ and not $E=QV$;in other words, why we multiplied it by $\frac{1}{2}$?? My ...
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76 views

Resistor and voltage drop [duplicate]

I know that a voltage drop of a resistor is the energy lost from the potential energy of the electrons.well, what i am really confused about is why the potential energy of the electron decreases as it ...
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Does voltage always cause current?

I'm wondering if the following statement is fully correct: Voltage causes current through a closed circuit, but through an inductor it is the change in current that causes a voltage. Obviously ...
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What happens to the resistance, voltage and current when DC passes through saltwater?

I have a circuit of a battery(1.5V or 9V) connected to a multimeter, a connected to 2 metal pieces in water(distilled)(see picture, in place of the LED is a multimeter). With the addition of salt 1. ...