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

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2
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3answers
225 views

How do electrons actually move in a circuit?

Last year, we were taught about electricity, about how electrons in a closed circuit. But as our teacher had not taught us about electric fields yet, she gave us a simplified model of motion of ...
0
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2answers
92 views

Parallel and series circuit problem

When two resistors, each of resistance 4.0 ohms, are connected in parallel with a battery, the current leaving the battery is 3.0 A. When the same two resistors are connected in series with the ...
0
votes
1answer
60 views

How similar is comparison between the principle behind Newton's Cradle versus AC Current moving down a transmission line?

Anyone who has taken high school physics has seen the following assembly. You drop one ball from the left hand side and the ball from the farthest right hand side gets knocked away. This is to ...
0
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1answer
47 views

AC circuit analysis: Why does current have the same frequency as the voltage?

The above example we have a 50hz AC voltage source. Why is that when we solve for I, I must have frequency of 50 Hz? Is there any phyiscal (non-mathematical) reason to explain this? Thank you
0
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1answer
1k views

Franck-Hertz Experiment explanation

Can anyone explain to me how the Franck-Hertz experiment works? (in term of electric current and voltage changes) I am getting all confused. More specifically, why is an accelerating grid (or mesh ...
0
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4answers
394 views

What happens in a circuit, when the wire and the battery are superconducting. And shorted

When a wire with no resistance is connected to the terminals of an ideal battery, will a current exist in the circuit? If a capacitor is added to the circuit, will it be charged by the battery or will ...
4
votes
3answers
12k views

Different batteries connected in parallel

If we have 2 batteries one of emf x and the other is of emf y and we connect them in series we get an effective emf of x+y. But what if we connect them in parallel, how to calculate the emf now?
-1
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2answers
89 views

Why doesn't a resistor dissipate reactive power? [closed]

Is there a (preferably microscopic) explanation for why a resistor does not dissipate reactive power?
2
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2answers
3k views

Voltage and Current in transformers

In transformers, the ratio of the voltages equals the ratio of the turns - so double the output coil's turns and the output voltage doubles. Then, in order to conserve energy, current halves. This ...
0
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1answer
33 views

Is real voltage always the real part of complex voltage?

If I have a complex voltage $V_z$ is real voltage $V$ (i.e. the voltage used in the normal ohms law and the voltage we normally talk about) always given by $V=Re(V_z)$. Does the same apply to current? ...
1
vote
2answers
57 views

Finding the current in a parallel circuit [closed]

Two resistors are joined as shown. The top resistor receives a current of 3 A. What is the current in the other resistor? What is the current that enters at junction A? I'm confused on how the two ...
0
votes
1answer
83 views

Am I solving this basic Kirchoff's current law and Ohm's law problem correctly?

After moving onto some of the practice textbook exercises in the section covering Kirchhoff's current law and Ohm's law, I came across a problem which evades my best attempts at solving it. Using ...
0
votes
1answer
61 views

What's wrong with this solution to freshman textbook example for Ohm's law and Kirchhoff's current law?

I'm a freshman taking an introductory course on circuit theory and I've run into a bit of trouble working through a textbook example practice problem. Unfortunately, it only lists the answer and not ...
2
votes
1answer
64 views

Current in an RC circuit inside in a magnetic field

Does my question make any sense? Context: The capacitor is charged with charge $Q_0$. There is a magnetic field $B=B_0 \hat{z}$ perpendicular to the monitor's screen. The length of the (AB) wire is ...
0
votes
3answers
73 views

How is voltage increased from a battery?

I have recently watched a video about a powerful Octa-copter that uses 30,000 Volt brushless motors to propell, the batteries however look quite small about a 19v laptop battery. How is the voltage ...
6
votes
2answers
2k views

How electric currents can flow between 2 points at the same potential?

According to Ohm's law, if there is a potential difference, $V$, across a resistor then there is a current, $I$, flowing through it. Since we assume that points along the connecting wire are at the ...
0
votes
2answers
27 views

Question about indutive loads in power system [closed]

Our home appliances are mostly resistive loads and the bill we pay for consuming power is actually real power. If we use more inductive loads at our home, will it just cause problems in power factor ...
42
votes
7answers
4k views

Cyclist's electrical tingling under power lines

It's been happening to me for years. I finally decided to ask users who are better with "practical physics" when I was told that my experience – that I am going to describe momentarily – prove that I ...
0
votes
3answers
77 views

What does raising voltage do?

If I raise the voltage of a wire from 0V to 1000V and then to 5000V, am I merely packing it with more and more electrons (with those electrons being trapped there until they find a path off the wire)? ...
6
votes
6answers
9k views

What would be the effective resistance of the ladder of resistors having n steps

I'm a tutor. This is a high school level problem. In high school, every one have might have solved a problem of effective resistance of a ladder of resistors having infinite steps. Now the problem is ...
1
vote
0answers
22 views

Unsure how resistors are connected? (Series/Parallel) [duplicate]

I am currently attempting this practice question in my tutorial and while I am able to reduce the circuit below to I do not know whether the 6/6/6/6 pane is connected in series or parallel, it ...
1
vote
1answer
84 views

Resistors in para and series circuit, finding volt [closed]

How anyone know how to do the question? I know how to reduce it to a window pane of 6/6/6/6 with a 3 in series but i have no idea how to do it. Well i did manage to reduce the right side of the ...
2
votes
1answer
119 views

Kirchhoff current loop in Resistor Diode Ladder network

I am looking for an approach on how to apply Kirchhoff current / voltage law in the infinitely long diode ladder network. Can anyone help me with this ? I am looking for 1D differential equation or ...
0
votes
1answer
39 views

Unsatisfactory explanation for the EMF measurement of a battery

Experimentally, I have seen how hooking up a battery to a simple circuit just with a high-resistance voltmeter raises the voltage reading (allegedly to a level equal to the EMF of the battery). ...
5
votes
6answers
7k views

Does a current carrying wire produce electric field outside?

In the modern texts of electromagnetism in the presence of stationary currents the electric field is assumed conservative $\nabla \times E =0 $. Using this we get $E_{||}^{out}=E_{||}^{in}$ which ...
17
votes
4answers
2k views

Are voltages discrete when we zoom in enough?

Voltages are often thought of as continuous physical quantities. I was wondering whether by zooming in a lot, they are discrete. I feel like the answer to the above question is yes as voltages in the ...
0
votes
2answers
48 views

potential difference in parallel connecting resistors

How could the potential difference be constant across all the resistors of parallel connecting resistors although each resistor has a specific resistance?
1
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3answers
270 views

How does Ohm's law apply to superconductors?

As radio amateurs we've all learned the various relationships of power, voltage, current and resistance as expressed in Ohm's Law. My question relates to the following simple circuit showing an ideal ...
1
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0answers
96 views

Concepts in Gabriel Kron's later papers

Gabriel Kron was an important research electrical engineer known for applying differential geometry and algebraic topology to the study of electrical system. Towards the end of his career he published ...
0
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3answers
53 views

Current in purely LR DC circuit at t=0

I was told by my professor that the current in a purely LR Circuit with at initial state (JUST after closing the switch) is zero. Can you please help me understand why it that so?
2
votes
2answers
127 views

Difference between $I^2R$ and $V^2/R$ and $VI$ for measuring power $P$

We use $I^2R$ or $V^2/R$ or $VI$ for measuring power $P$. Are all of these applicable for all circuits? I have seen in some circuit $V^2/R$ is not equal to $I^2R$. Why is that?
2
votes
2answers
236 views

Battery and current confusion?

How exactly does a battery produce a current in the circuit connected across its ends? I dont want to know the chemical reactions in the battery core, but just the essence of it. I believe it doesn't ...
11
votes
8answers
10k 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 ...
2
votes
1answer
68 views

Ambiguity on the notion of potential in electrical circuits?

As everybody else I have been taught elementary electrical circuits from secondary school to engineering level in analog electronics at university. Invariably, the notion of potential used to ...
1
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3answers
399 views

Potential difference (PD) and electromotive force (EMF) in terms of electrons?

I am trying to understand potential difference and electromotive force in terms of electrons. In the above 3 circuit diagrams the red shows (what I think to be) the distribution of electrons ...
0
votes
1answer
27 views

Current in a circuit with resistors and capacitors

Suppose we have a circuit with both resistors and capacitors and some voltage source. If we want to calculate the current in the circuit, do we apply Ohms law? My doubt is that this would only take ...
0
votes
2answers
122 views

Energy stored in a capacitor in an RC circuit

Suppose we have a capacitor of capacitance $C$ and a cell of emf $E$, why is the maximum energy stored in a capacitor equal to $\tfrac{1}{2}CE^2$? I feel confused because, the potential difference ...
3
votes
2answers
113 views

How are electromagnetic waves differentiated?

I would like to know how the signals for remote controlled cars, radios, etc.. That use radio waves are told apart from each other. I know that the radio waves are modulated to encode data and the ...
1
vote
3answers
102 views

Current through two inductors after a long time

I'm having trouble with visualizing the following problem, which is asking me for the final, steady current in both inductors $L_{1}$ and $L_{2}$. I was thinking that after a long time, essentially ...
1
vote
1answer
136 views

Is there inductance to a DC circuit?

When a DC circuit is carrying current, large amounts or small, is there induced-emf due to the inductance? Or is it only applied to AC circuits?
1
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2answers
90 views

Would magnetic flux be necessary for analogous systems?

I learned about the analogousness between mechanical and electrical systems a few months back (with the help of Feynman). Yesterday, my professor was lecturing about this topic, when she told that ...
1
vote
1answer
76 views

Interpreting Physics Results Regarding Circuitry Analysis (Highschool Level Physics) [closed]

I conducted an experiment which aimed to detail and record the voltage across series resistors in series circuits. I noticed that: The Final Voltage, V3, stayed the same. The resistors with the ...
3
votes
3answers
2k views

Equivalent resistance in ladder circuit

I have stumbled upon a given question I really have a hard time to solve. Basically I need to find an equivalent resistance in some form of "ladder" configuration. Where the chain is an infinite ...
3
votes
5answers
4k views

Why are AC quantities represented by sine waves always?

Usually we use a sinusoidal wave form to represent a alternating quantity. Why not a cosinusoidal wave or a ramp wave form? In sine wave forms we can indicate the maximum and minimum amplitude and ...
1
vote
2answers
302 views

Simultaneous Charging and Discharging Capacitor

sorry if I sound little noobish. Though I have a fairly good understanding of physics, I sometimes don't understand the electrical aspects. Say there is a capacitor. This capacitor is expected to act ...
6
votes
1answer
253 views

Reluctance of torus shaped iron core with embedded wire loop

Imagine a circular wire loop (r = 50mm), the wire has an assumed diameter of zero, which is embedded in a torus shaped iron core with a circular cross-section of R = 10mm. A current in that loop ...
-2
votes
1answer
33 views

Calculate the current in mA which will be flowing through the two resistors [closed]

Three resistors of 3,4 and 5 ohms are joined in parallel in an electric circuit. If a current of 150mA flows through the resistor of 4 ohms,then calculate the values of the current in mA which will be ...
2
votes
1answer
49 views

Using the loop rule while charging circuits

We know that in an LC circuit the voltage across the capacitor is the same as the voltage across the inductor (the emf induced in it). This is a direct conclusion of KVL (Kirchoff's Loop Rule) applied ...
3
votes
2answers
176 views

Why does smashing a TV remote load its batteries?

Many times I had the same problem: my TV remote's batteries were too weak for it to operate, but then, when I shook the remote a bit and smashed it on my palm, somehow the remote regained its ability. ...
0
votes
1answer
4k views

Does the phase difference between voltage and current in an LCR circuit exist throughout the circuit?

I know that in an purely inductive circuit the current lags behind voltage by $90^o$, in a purely capacitive circuit vice-versa and in an LCR circuit the current may lag or gain with respect to ...