The electric-circuits tag has no wiki summary.
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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 ...
16
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4answers
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Why do 'dead' batteries work again after exchanging the places of the batteries in an electronic device?
My camera, which is powered by two AA batteries in series, would not power on. I removed the batteries, exchanged their locations, and the device worked again - for another 15 minutes or so.
The ...
14
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3answers
551 views
Distorted colors of Google StreetView photographs near electric power lines
This is a followup to my question:
Cyclist's electrical tingling under power lines
Some users presented a convincing picture that the electric shocks under power lines are primarily from the ...
12
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2answers
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The “Nerd Sniping” problem. Generalizations?
This question is motivated by this xkcd comic strip
.
The problem is indeed interesting, and my first recollection upon reading this was a similar problem in the book Problems in General Physics by ...
9
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3answers
303 views
Current in a simple circuit
I was going over my notes for an introductory course to electricity and magnetism and was intrigued by something I don't have an answer to. I remember my professor mentioning, to the best I can ...
9
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1answer
774 views
Matrix solution of an equivalent resistance circuit problem
Start with a set of points $x_1, x_2, \ldots$ that are connected by wires with some resistance. Represent the resistance by a conductance matrix (conductance being one over the resistance), where ...
7
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1answer
439 views
Can an arbitrary RLC-circuit network have non-minimum phase zeros?
I am working with certain input-output maps that can be thought of as large RLC-networks. I thought maybe this might be a place to get some thoughts/ideas/answers.
My basic question is, given some ...
6
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1answer
446 views
Why does breaking one bulb on a string of Christmas Lights cause all the rest to break in some lights?
If I break one bulb on a string of Christmas lights, or the filament goes out, then all of the rest seem to stop working. Why is this?
However, I've also seen the opposite happen in some newer ...
6
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2answers
264 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 ...
6
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2answers
690 views
Lots of little questions about radiation of LC circuits
I'm trying to get a more intuitive understanding of resonant inductive coupling. It's supposed be a more efficient way to transfer electrical energy wirelessly, because the coils are only coupled by ...
5
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4answers
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Resistor circuit that isn't parallel or series
What's the equivalent resistance in this circuit (between points A and B)?
5
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5answers
684 views
How long would it take for electricity to flow from one terminal to other, via a 1 LY long wire?
Basically, how long does it take for electricity to determine there is a closed circuit and how does it know that the circuit exists? I'm curious to know how it knows there is a closed circuit at any ...
5
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2answers
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Modeling stochastic process with frequency-dependent power spectrum
I'm trying to model of Johnson-Nyquist noise propagation in a nonlinear circuit. An ideal (linear) resistor can be modeled very nicely by the Fokker-Planck equation (equivalently, the drift-diffusion ...
5
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3answers
281 views
Why can't a superconductor make a DC motor self sustaining?
Superconducting wire can host a low current magnetic field. I do not know if it supports a corresponding electrical field.
Can a superconducting wire that sustains a current accelerate a DC motor? ...
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5answers
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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 ...
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6answers
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In an alternating current, do electrons flow from the source to the device?
If electrons in an alternating current periodically reverse their direction, do they really flow? Won't they always come back to the same position?
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3answers
224 views
Why don't electric workers get electrocuted when only touching one wire? [duplicate]
I know that when electricians work on the poles on the streets, if they only touch one wire at a time they will be fine. However, from my understanding, the negative wire is connected to a large ...
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3answers
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Why do we use Root Mean Square (RMS) values when talking about AC voltage
What makes it a good idea to use RMS rather than peak values of current and voltage when we talk about or compute with AC signals.
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2answers
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What are the effects of cosmic rays on consumer electronics?
When electronics/computer companies design a new chip, processor/ memory card/ or a solar cell, do they study the effect of cosmic rays on such electronically sensitive materials? If not, why not?
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1answer
673 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 ...
4
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1answer
77 views
How does my hand amplify an FM radio signal?
I have a gizmo that broadcasts an FM radio signal from my phone's headphone socket to my car's radio antenna.
Sometimes, there's another station on the same frequency with a stronger signal and my ...
4
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2answers
46 views
Equivalent RC circuit to a RRC circuit?
I'm in doubt about a situation that I've seen sometimes: imagine we have a resistor in parallel with a resistor and a capacitor in series. Since I don't know how to generate figures of circuits to ...
4
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2answers
941 views
Strategies against 50 Hz mains hum on detector signals?
I'm having problems with a strong 50 Hz mains hum on signals created by photodetectors. I assume that they are due to ground loops and I realize that the best option would be to remove those. What are ...
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2answers
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1answer
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General integral to find resistance
My question is: is there a simple and truly general equation for the resistance between two electrical equipotential surfaces?. Obviously, if so, what is it, and if not, why? It would be very ...
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2answers
448 views
Derivation of Ohm's Law
Is it possible to derive Ohm's law (perhaps in some appropriate limit) from Maxwell's Equations?
3
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1answer
90 views
buiding circuits from color superconductors
caveat: the sort of exotic matter engineering in here is currently beyond the reach of our technology, but, that having been said:
Has their been any research on building models of these sorts of ...
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2answers
541 views
Relating milliampere-hours to watt-hours for batteries
I've seen many batteries that are measured in milliampere hours (mAh), while others are measured in watt hours (wh). How can I convert them between each other so that I can actually compare them? It's ...
3
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2answers
411 views
Capacitor circuits with light bulb
Let's say we have a normal circuit with a light bulb, with wires and a battery.
When one places a capacitor in this circuit, how is the light bulb able to light up, even when the capacitor prevents ...
3
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2answers
304 views
The role of resistor in e.g. an AND gate
What is the role of the resistor in e.g. an AND gate like this one? :
One often sees lots of resistors in electric circuits, but I haven't really understood their role.
3
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1answer
119 views
Path of an electron through an electric circuit
When a potential difference is applied across a conductor, and if an electron moves from the negative terminal of the battery and reaches the positive terminal, then I want to know if the electron ...
3
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2answers
87 views
How can a circuit function with two negative battery terminals facing each other?
Here is a drawing of the circuit that is confusing me:
I don't quite understand how batteries work in this diagram. If a battery has a negative and positive terminal, there must be a barrier ...
3
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1answer
176 views
Explanation of the Graetz circuit
My knowledge of circuits is pretty rudimentary and I've never really understood circuits, so I'm having trouble with the concept of Graetz circuits:
When you register the voltage on the resistor R ...
3
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3answers
217 views
What is the current through the lamp?
We have the following circuit:
A neon lamp and a inductor are connected in parallel to a battery of 1.5 $V$. The inductor has a 1000 loops, a length of $5.0 cm$, an area of $12cm^2$ and a ...
3
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2answers
166 views
Instantaneous current after battery unplugged in RL circuit?
I've been racking my brain over this, and I can't find any clues in my textbook as to how to approach it.
I have the following circuit:
My goal is to find R such that, right after the switch is ...
3
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2answers
203 views
Electrostatic notion of voltage as it applies to circuits
I have a question that's been bothering me about electric fields, voltage, and circuit analysis.
Initially, I came to understand voltage as it was taught in the context of electrostatics - through ...
3
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1answer
124 views
How are quantum potential wells fabricated?
Potential wells, such as infinite and finite potential well, have been the standard examples in quantum mechanics textbooks for tens of years. They started being only theoretical toy models but as ...
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0answers
237 views
Turn-on delay time for Laser diode
Do you know any simple explanation on the reason why the turn-on delay time on a laser diode is reducing while we increase the bias current?
Turn on delay,is the time that the laser needs from the ...
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3answers
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How much energy was consumed when we turn on/off light?
My parents told me to turn off the light when I am not using it. But I remember my physics teacher told me that the action of turning on/off a light can cause huge energy. I am wondering how much is ...
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4answers
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How does power consumption vary with the processor frequency in a typical computer?
I am looking for an estimate on the relationship between the rate of increase of power usage as the frequency of the processor is increased.
Any references to findings on this would be helpful.
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2answers
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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 ...
2
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1answer
635 views
Current from induced emf
If the induced emf in a circuit is negative, and current from this emf is the emf over the resistance, what happens to the negative sign in the induced emf when solving for the current? Surely there's ...
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3answers
655 views
is it possible to flow current in open circuit?
First , i don't know much about chemistry and physics. I'm just a graphic designer but i have this question in my mind. I'm sorry if this question is too basic and use 'generic' language.
As i know ...
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3answers
309 views
How does energy depend on frequency in an alternating current circuit?
In what relation is the energy input in an alternating current circuit to its frequency?
I'd guess I have to compute something like
$$E=\int P(\omega,t) dt=\int U(\omega,t) I(\omega,t) dt, $$
but ...
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2answers
700 views
What is the potential difference between point X and point Y?
Here is the problem:
In the above figure I want help on finding the potential difference between X and Y.
It is getting quite confusing due to the battery in the middle. I found the current in both ...
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3answers
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Wheatstone Bridge
Why is using a Wheatstone bridge such an accurate way of calculating an unknown resistance? What are the benefits of using it over Ohm's law?
It seems that it has something to do with the wires ...
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2answers
137 views
Why does a capacitor discharge?
Suppose a charged capacitor (parallel plates), the negative and positive charges on two plates attract each other. Which force cause the negative charge carriers (electrons) move through the circuit ...
2
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1answer
152 views
Positive test charge
Protons have positive charge on them. Protons aren't mobile. So how can a positive test charge move from the negative terminal of a cell to the positive terminal and gain electric potential energy? ...
2
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1answer
188 views
Power dissipated in resistor
Suppose one has a circuit consisting of an inductor $L$ and resistor $R$ in series where $L$ and $R$ are known, passes an alternating voltage of frequency $\omega$ through it and that one wishes to ...
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1answer
364 views
Electrical flow in a simple parallel circuit
I'm having trouble understanding something in one of my text books:
Let’s have a look at the implications of each circuit configuration.
Figure 3.13 shows the Conventional representation of a ...
