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

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Question regarding Kirchoff's loop rule

My problem is that there are n cells connected in parallel which are connected to an external resistor. Now can we use Kirchoff's loop rule to evaluate the current through the resistor by considering ...
8
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7answers
385 views

Why is the resistance in a parallel circuit smaller than the resistance in a series circuit?

So I was told in the physics class that the resistance in a parallel circuit is smaller than the resistance in a series circuit. Why does that happen? Is this statement also true for circuits which ...
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0answers
11 views

frequency passage inside AC ciruit

I've been checking YouTube about AC circuit lesson and been hearing about inductor passing low frequency and capacitor passing high frequency from alternating current and what does that mean by ...
0
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0answers
18 views

How do I calculate the effective resistance in this circuit? [closed]

How do I calculate the equivalent resistance across A and B when i) All resistors have a resistance in the given circuit of $~\mathrm{R }$? ii) The resistors in the given circuit have values as ...
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1answer
15 views

Range of voltmeter [closed]

I have understood how the range of an ammeter cannot be decreased. But I don't seem to understand how the range of a voltmeter can be decreased. Pls help.
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1answer
32 views

Same current flowing [closed]

In the following circuit how can we say that the current flowing through both the $4\Omega$ would be same . I know it would be same if in middle the $\frac{2}{3}\Omega$ is not there but here it is ...
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3answers
74 views

Infinite staircase where each step is a 1 ohm resistor [closed]

There is an infinite staircase where each step is a 1 ohm resistor. How do you calculate the equivalent resistance between any of the two points on the staircase?
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1answer
38 views

Circuit with voltage source, resistance and current source

Suppose I have a (closed) circuit with a voltage source $V$, a resistance $R$ and a current source $I$ (in this order). Is it true that the voltage across the current source is $V-RI$ ?
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1answer
45 views

Is it true that in a superconductor the current will always flow without a any electric source? [closed]

It came to my mind that when a superconductor is taken and a wire is joined to it to make it a complete circuit, the current is flowing through it. Now, I am removing the battery and joining the two ...
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2answers
64 views

Electrical equivalent of inverted pendulum

Background I am working on a summer project to design labs for undergraduate students. One of the topics is feedback and there is already quite a lot of stuff about passive feedback, so we might add ...
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0answers
16 views

Relaxation Time in RC Circuits with a Metal Conductor

In section 4.8, Variable Currents and Capacitors, of Purcell and Morin's Electricity in Magnetism, the following is discussed: For a metal with resistivity typically $10^{−7}$ ohm-meter, the time ...
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1answer
30 views

Energy dissipation in current flow

In section 4.8, Energy dissipation in current flow, of Purcell and Morin's Electricity in Magnetism, the expression for the power expended by a resistor is derived. The sections includes the following ...
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0answers
65 views

Can the Hall effect drive a current?

In the Hall Effect current is passed through a wide strip of metal in a perpendicular magnetic field. Since (some of) the negative charges in the metal move but the positive ones stay put, the ...
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1answer
52 views

Equivalent Resistance between 2 points

Actually , I'm having trouble in solving for the net resistance of the below network of resistors. Can anyone help me finding the equivalent resistance between points a & b. My answer is $2/3r$...
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1answer
42 views

Determining if two resistors are in series or in parallel. [duplicate]

I know that this is a rather trivial question, but I've been having issues developing a problem-solving strategy for figuring out whether resistors are in parallel or in series. The Specific problem ...
-3
votes
2answers
42 views

Why would a series of cells not be suitable for a car battery? [closed]

A car battery needs to supply a current of $200A$ to turn over the starter motor. Explain why a battery made of a series of cells would not be suitable for a car battery. My thinking: I'm thinking ...
-1
votes
1answer
102 views

What is the voltage drop across a wire [closed]

If we attach a resistor in series, most diagrams only consider the voltage drop across the resistors. What happens when we remove all of the resistors? Why does the voltage drop across the wire become ...
0
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1answer
42 views

Electric potential in a wire

I am slightly confused on the physics of direct electric circuits. Here is what I have been taught: Batteries (sources of emf) provide a constant potential difference between its terminals; ...
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0answers
19 views

Which AC bridge circuits are oscillators? [migrated]

There are different types of AC bridge circuits like the Wheatstone bridge, Maxwell, Hay, Shering and Wien. I need to know which ones are oscillators but I still don't get the main reason why the ...
1
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1answer
63 views

Differential equation in RL-circuit

I am self-studying electromagnetism right now (by reading University Physics 13th edition) and for some reason I always want to understand things in a crystalclear way and in depth. Now look at this ...
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1answer
80 views

Work done by the battery in series with capacitor with changing dielectric

If we have a battery with voltage $V$ connected in series with a parallel-plate capacitor of capacitance $C$ with dielectric $\epsilon$,and then we pull the dielectric out, the infinitesimal work done ...
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0answers
25 views

Resistance increase with length because of more scattering?

I am referring to one of the answers to this old question. I can't add comment to it because I don't have enough reputation. So here I rephrase the question: does resistance increase with length ...
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1answer
20 views

By which equivalent circuit (RC serie or RL serie) can I substitute the following circuit?

I was trying to solve the following question: "Assuming that 𝐑 = 𝟏𝐤𝛀, 𝐂 = 𝟏𝛍𝐅, 𝐋𝟏 = 𝟔𝐦𝐇, 𝐋𝟐 = 𝟑𝐦𝐇, 𝐞 𝛚 = 𝟏𝟎𝟒 rad/s, tell if the circuit can be substituted by an equivalent RC ...
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1answer
45 views

Even when the drift velocity of the electrons is very small, how is current in the circuit established immediately?

So I have this question in my textbook and Ive also got it in my test. Ive written a wrong answer. My friend wrote the drift velocities of each particle add up and he got full marks. Is it right? Can ...
0
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1answer
39 views

Earthing, neutral and Earth's conductivity

Ok so this is gonna be a lot of mini-questions. What exactly is the neutral wire? How does earth conduct electricity for a live AC mains even though its just dirt and stones (it should be an ...
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1answer
50 views

What happens when an AC source is connected to a capacitor and a LED?

When a DC source is connected to a capacitor and a LED, and the voltage is removed when capacitor is charged, the capacitor supplies current to it for some time. What happens if this DC source is ...
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1answer
36 views

Laser as an optical oscillator

How can Laser can be compared to a positive feedback amplifier? Does the two conditions for oscillator holds good for lasers too.
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1answer
25 views

holes in an electronic circuit [closed]

Many times, by looking at electronics circuits I noticed that they have like small holes printed in yhem. The question I want to ask is, what s the purpose of these holes?
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1answer
49 views

Resistor in series

We know that when a resistor is connected in series , the current flowing through that resistor will be constant.But how do we use a resistor to limit the current flowing through a circuit ,when ...
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2answers
27 views

Elementary derivation of $P = UI$ starting from the definition of voltage as work done per unit charge

Consider the following elementary derivation of the formula $P = VI$ for Joule heating of a resistor $R$ for the dissipated power $P$ where the voltage over the resistor is $V$ and the current $I$. ...
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1answer
60 views

Proof of Kirchoff's second law [closed]

There are 2 approaches I have stumbled to prove Kirchhoff's second law: Derive it from the conservation of energy. You can derive that from "integral of E*ds = 0". Can you show me a full or at ...
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0answers
53 views

Minus sign in analyzing RC with changing emf circuit?

I'm learning electromagnetism from Purcell's book. He say that if we have the following circuit: $$-\frac QC + RI = \mathcal E_0\cos\omega t~,\quad I = -\frac{\mathrm dQ}{\mathrm dt} $$ The ...
0
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1answer
38 views

Possible reasons of electrocution in a good earthed appliance during sudden power off [closed]

I was working in a industry. When I was using a machine, I felt slight electrical shock at the exact moment when the power supply went off. The machine is properly earthed. In spite of that I got ...
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0answers
16 views

What's the back EMF on a spherical conductor suddenly surrounded by a negatively charged shell?

Suppose one has a spherical conductor of radius r. Suppose it is suddenly surrounded by a negatively charged shell. The conductor will rush to balance out the voltage. However, this changing current ...
0
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1answer
19 views

When happens to the current during reversed biased?

The main working function of a half wave rectifier is to convert AC current to DC. My problem is to understand during the negative cycle. The above picture is time versus current. We can see easily ...
0
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1answer
52 views

Why Thevenin's theorem is being violated?

in the given picture we need to find the current flowing through the 3 ohm resistor. Applying KVL we can find the current as 4 amps but if we thevenise the circuit at terminal a-b then the current we ...
0
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1answer
39 views

Behavior of coil and resistance in DC circuit [closed]

I have a simple circuit of a coil parallel to a resistance and then in series with another resistance. I wanted to understand the behavior of this circuit so I ran a simulation, and what I noticed is ...
0
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1answer
20 views

Is peak voltage or peak current kept constant when we change resistance in an AC circuit?

I found online that Ohm's law still applies to an AC circuit and that $V_{peak} = RI_{peak}$. However, I can't seem to find anywhere weather an AC source will : Act as a voltage source and keep its ...
2
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0answers
66 views

Circuit theory paradox - Unexpected results [closed]

I recently studied capacitors and found out that there is something called 'ideal circuit paradox'. Searching Google I found that one can cannot find the potential difference between two points in a ...
0
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2answers
56 views

Why is there only a drop in potential energy when charges flow through a resistor?

First, I read that if you move a charge (say a positive charge) against an electric field, its electric potential energy increases because you're doing work to move the charge to that position. I also ...
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1answer
43 views

Different voltage drops depending on the path

I was working through a problem in electromagnetic induction when I discovered that I have a fundamental ignorance of some sort that is puzzling me. Consider a circular wire, at rest, perpendicular ...
1
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1answer
34 views

Is it possible to measure the resistivity of something using A.C. Current and a capacitor?

I've read that A.C. current "passes" through a capacitor. Is it possible to use this and measure the resistivity of the medium between the plates? Any sources or links would be appreciated.
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votes
1answer
26 views

Armature of electric bell [closed]

I want to know that why is the armature of the electric bell made up of soft iron ? I googled this out and everywhere it was written that it is because of its propert to aquire electromagnetism but I ...
-2
votes
1answer
65 views

Resistor homework assignment: 7 resistors with connected triangles [closed]

I am a lost in how to solve this problem, since I don't how where to start. The questions doesn't inform any voltage or current, asking only the equivalent resistance of the circuit. All resistors ...
0
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1answer
57 views

Resistance Distance in large electrical networks

I am not tremendously familiar with electrical circuits (I have some memories, but too long ago) and now I have come accross a problem where I need to compute the resistance distance in a graph. So, ...
0
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3answers
25 views

Difference in directions of charge and current.?

I just dont understand that why does charge flow in a different direction as that if current when current is the rate of flow of charge.
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2answers
33 views

Why is it that for a source of emf, current flows from lower to higher potential?

I'm quite confused about this actually! In fact, I had always thought current flows from a region of higher potential to a lower one. Does it have anything to do with the fact that it's a source of ...
-1
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1answer
41 views

How does voltage produce current?

I am studying electric current and i dont understand how does voltage(potential difference )produce current? PS : I am a 10th grade student so please avoid complicated terminologies.
-1
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1answer
25 views

Current flow in absence of a potential difference [closed]

What if at two different points in a wire connected to a system of capacitors and resistors, the electric potential is equal. Will the current flow? There is also a battery connected.
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3answers
55 views

Ohm's law and an ideal voltmeter

In an ideal voltmeter there is infinite resistance so because of which no current is flowing through it and the voltage reading is not affected. The ohm's law stated that V = I * R In an ideal ...