An electronic system, with closed loop current flow, and relative electrical potentials present across electrical components.

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How can be the neutral wire at 0 volts when current flowing through it?

Voltage is potential difference, and current flows because of voltage. So if the voltage is zero, how can current flow through the neutral wire.
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290 views

Calculating the resistance of a 3D shape between two points

If I have an arbitrarily shaped object made of a uniform material of some specified resistivity, how would I go about calculating the resistance between two measurement points with known contact ...
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3answers
237 views

What happens to half of the energy in a circuit with a capacitor?

For a simple circuit with a battery supplying a voltage V to a capacitor, let us assume that the charge on the capacitor is Q. Now, the work done by the battery or the energy supplied is given by the ...
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2answers
870 views

Rate of flow of electrons in a simple circuit, given the current? [closed]

I have this question: The correct answer is C. I understand that the flow of electrons should be from Y to X because electrons flow opposite to "conventional current", which is from positive to ...
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2answers
406 views

Why is there no induced electric field in the experiment (Faraday's Law)

Below are three circuit diagrams for each of Faraday's experiments that allowed Faraday to come up with Faraday's Law. In Griffiths' Introduction to Electrodynamics Griffiths states (on page 302 of ...
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2answers
710 views

Why do high voltage transmission line workers need a Faraday cage suit?

In this video the high voltage transmission line workers are wearing a Faraday cage suit. Why is this needed? Without the Faraday cage, the resistance of the human would be very high compared to the ...
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1answer
61 views

Potential difference in a circuit of n cells = 0? How?

I was supposed to find the potential difference across any one cell in an arrangement consisting of n cells of EMF E connected in series in a closed circuit and internal resistance r. I proceeded by ...
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1answer
48 views

How will open-circuit voltage affect the Fermi Level Difference

The circumstances of my question consists of this: I have two materials, copper and cesium, and they are sandwiched together with a layer of cesium in the middle. It is connected only on a single side ...
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1answer
662 views

How does a bulb light up when it's connected in a circuit with an uncharged capacitor and a cell?

Since there is a capacitor, isn't it an incomplete circuit? How does the current flow across the dielectric medium? If a bulb was connected to a cell alone and if there was a break in the wires of the ...
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0answers
13 views

Current pass through different branch of network [duplicate]

How current knows that resistance in any branch of network is law show that more proportion of it pass through that branch?
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4answers
38k views

Why does connecting a battery's positive terminal to the negative terminal of another battery not create a short circuit?

This is a question regarding the physics behind the observation. I have guessed the answer to the question, but I may be wrong, so I want to wait for the responses before posting it. Some major ...
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1answer
8k views

short circuit an alkaline battery

i'm not doing anything related to physics, but i'm just curious : What really happen when i short circuit an alkaline battery ? some article in the net shown that fire/explosion can be happened when ...
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2answers
82 views

Why is this circuit component on without a potential difference?

From the following graph, determine whether (h) will be on or off: I think (h) should be off because there is no potential difference across it. Is this correct? Edit: Using the method provided ...
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1answer
382 views

Series / parallel capacitor network: find two capacitances and source voltage given some measured data

Capacitor 3 in Figure (a) is a variable capacitor; its capacitance $C_3$ can be varied. Figure (b) gives the electric potential $V_1$ across $C_1$ versus $C_3$. The horizontal scale is set by $C_3 = ...
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1answer
102 views

Transfer function of an RC circuit

I'm trying to reach the transfer function of an RC circuit which I am told is $$\frac {V_R} {V_\text{in}} = \frac{R}{\sqrt{(R^2 + \frac {1}{\omega^2 C^2})}} \cos(\omega t - \theta) \, .$$ Is this ...
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1answer
75 views

About the combination of two signals with capacitors

Here is a link of an article I've been reading. http://www.analoguehaven.com/moog/thereminblack/hotrod.pdf In page 4 there is a circuit schematic. Notice there is a part called variable pitch ...
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2answers
311 views

How long does it take for a capacitor to be fully charged if voltage is decreased? [closed]

Above is the picture of the circuit pertaining to this question. The question asked for the time it will take for the capacitor to get fully charged when the switch is in position B? So i guess the ...
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0answers
115 views

Does voltage depends on the charge present in an element?

Does the voltage depend on the charge present in a battery ? I know in capacitors q=cv. Hence charge present is proportional to voltage. Is it the same in the case of batteries?
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71 views

Approximate of self-inductance of a square wire coil

Imagine you have a square coil of wires with n turns. In order to calculate the self-inductance coefficient I should know the magnetic field. Is it acceptable to consider the 4 sides as infinitely ...
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1answer
2k views

Why are ammeters used in series and voltmeters in parallel?

As I'm reading a course on electricity, this one says that an ammeter should be branched inline and not on a bridge. Can someone explain to me physically why we branch a amperemeter inline and a ...
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2answers
4k views

Tying knots in power cables to prevent power surge from lightning strikes

There are plenty of references to this claim on the internet that tying knots in power cables will prevent a piece of equipment e.g. television or computer from a power surge. How can this be ...
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11answers
19k views

What is the difference between electric potential, potential difference (PD), voltage and electromotive force (EMF)?

This is a confused part ever since I started learning electricity. What is the difference between electric potential, potential difference (PD), voltage and electromotive force (EMF)? All of them have ...
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2answers
60 views

A circuit that is net charged

What differences would you measure if a circuit were significantly charged negatively? Would the resistance change? To be clear, I mean that excess electrons are added to the system. The circuit can ...
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3answers
143 views

Induction on a circuit with switch

I have the following circuit: It is subject to a steady, time-invariant magnetic field which points out of the paper. At $t = 0$, the switch closes. I thought that the magnetic flux would decrease ...
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2answers
44 views
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1answer
52 views

Will the current flow from the battery?

I am just trying to find out if the current enters into the positive terminal of the battery (if there is a battery with bigger emf ) will it get charged and charge will be stored and current will ...
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2answers
580 views

How to accurately mark with arrows an electric circuit

As I understood, we choose to mark the current with arrows going from the plus pole to the minus pole (even though we know that in reality it is the contrary). As I'm looking at electric circuits, I ...
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4answers
300 views

How does an inductor store magnetic energy?

I am trying to figure out what the potential energy of an inductor with a current really means. In a capacitor, the energy stored works like this: if you let the plates attract each other, before ...
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2answers
61 views

Doubt on resistor circuit [closed]

How are we able to flip the triangular resistor to the opposite breaking its connection with the lower 2r resistor?
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5answers
2k views

What causes contact resistance?

When two components are combined in an electric circuit, there is apart from their own resistances a contact resistance at their junction. This causes a sudden voltage drop of ...
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2answers
68 views

Why is voltage essential in circuits?

I understand what voltage is, but why is it necessary for an electric circuit to function? Why can't current flow without a voltage?
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32 views

What is the capacity of this circuit? [duplicate]

I simply can't figure out what the capacity of this circuit is. I can do the math myself, I just need a hint how to create an equivalent circuit where it is obvious what is parallel and what is in ...
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1answer
109 views

Highly inductive circuits question in general

I've been reading about self-inductance in circuits in M. Purcell's Electricity and Magnetism and came across an interesting fact: "What happens if we open the switch after the current $I0$ has been ...
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1answer
141 views

Electric Motors: why do they draw more current when stalled, and less when moving? [duplicate]

I'm familiar with how an electric motor works, and also familiar with what stall current and free current refers to in an electric motor. I'm also somehow familiar with the notions of energy being ...
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1answer
50 views

Does the power of the resistor change when the battery is changed?

Wanted to know whether the changing of a battery (potential difference)affects the change of power consumption of a resistor of a bulb. please tell me how the change will occur?
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1answer
161 views

Does the skin effect, eddy current / hysteresis losses contribute to Johnson noise in an inductor?

Based on my very basic understanding of the Johnson noise, it's not just a DC phenomena, but should change with frequency in a system, where there is a frequency dependent, real component to the ...
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1answer
59 views

Are LC circuits preferred as series or parallel? Why? [closed]

Are LC circuits preferred as series or parallel? I recently studied about LC circuits in parallel and asked my tutor about whether the inductor and capacitor could be connected in series. He said it ...
65
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2answers
44k views

On this infinite grid of resistors, what's the equivalent resistance?

I searched and couldn't find it on the site, so here it is (quoted to the letter): On this infinite grid of ideal one-ohm resistors, what's the equivalent resistance between the two marked nodes? ...
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3answers
7k views

Proof of Thevenin and Norton theorem

How can I prove Thevenin's and Norton's theorem? Thévenin's theorem can be used to convert any circuit's sources and impedances to a Thévenin equivalent.
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84 views

Kirchoff's circuit law matrix representation

A couple of recent Kirchoff's law questions with wacky geometries got me thinking. "Solving" any circuit that consists only of resistors and e.m.f. sources can be reduced to solving a linear system of ...
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1answer
70 views

Calculating resistance [duplicate]

I am really confused please help me! I want to find the resistance between a and b! But i am not able to understand which resistances are in series or which are in parallel! What i think- e and a ...
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2answers
7k views

Conversion of Moving coil galvanometer to ammeter

A galvanometer can be converted into an ammeter by connecting a low resistance (called shunt resistance) in parallel to the galvanometer. Firstly, why do we need to connect the resistance? If a ...
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2answers
197 views

potential difference across a bulb

I am doing some self studying over the summer for fun and I'm working from a book that does not provide answers. I came across the following question, and I will present my solution. I was hoping ...
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0answers
20 views

Total current - differential equation [duplicate]

Consider the circuit below consisting out of a capacitor C and two identical resistors R. For $t<0$ the switch is open and the capacitor is uncharged. At $t=0$ switch is shut and the circuit is ...
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0answers
75 views

LC-circuit with AC-supply - Current flowing through the coil

A parallel LC-circuit is connected to an AC-supply as in the figure below. $I_{tot}(t)=I_0sin(\omega t+\phi)$, $\phi$ is the phase angle between $V_{tot}(t)$ and $I_{tot}(t)$ a) ...
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3answers
264 views

Why do inductors maintain the exact same current?

As we know, a capacitor will maintain the same voltage across its poles even if it is disconnected from a battery source. For example, in this problem: http://www.unm.edu/~toolson/rc_circuit.gif ...
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1answer
359 views

Circuit with capacitor and two resistors - total current - charge - differential equation [closed]

Consider the circuit below consisting out of a capacitor C and two identical resistors R. For $t<0$ the switch is open and the capacitor is uncharged. At $t=0$ switch is shut and the circuit is ...
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1answer
356 views

Loss in energy while charging a capacitor

Suppose a capacitor having capacitance $C$ is being charged using a cell of emf $E$. By the time the capacitor is fully charged, the cell has supplied $QV$ energy while the potential energy of the ...
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2answers
696 views

Energy conservation when capacitor charges in a zero resistance circuit

We know that when a capacitor charges from a source $E$, it stores energy of $E=\frac{1}{2}QV $. This is derived without taking into consideration any resistances present in the circuit. We also ...
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78 views

Maximum current in LC Circuits

Two capacitors of capacitance $C$ and $3C$ are charged to potential difference $V_o$ and $2V_o$ respectively and connected to an inductor, all three in series. Now the switch S is closed. Find the ...