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

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Equivalency of Q Factor Definitions

The Q factor is defined (seemingly) as $$Q=2\pi\frac{\mathrm{energy \, \, stored}}{\mathrm{energy \, \,dissipated \, \, per \, \, cycle}}$$ however on Wikipedia is says that the Q factor can be ...
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67 views

Why is the current measured through a thin film increasing with time? (experimental question)

I'm doing an experiment: I'm thermally evaporating a metal in a vacuum onto a quartz (very insulating) substrate, between two gold contacts that I use to measure the current through the (growing) ...
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271 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 ...
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151 views

The origin of contact noise?

I was trying to measure the noise of a device with metal probes. I was not sure whether I should trust the results because I was told contact noise might contribute to some degree. I am a little ...
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15 views

How to apply kirchoff's laws to motors in DC and AC settings

DC case: is it ok to treat a motor as a variable resistor, with resistance depending on the load? AC case: suppose I have a motor that runs at 120V AC and is rated to X watts, how can I determine how ...
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25 views

Electric circuit for nonlinear pendulum?

Is it possible to make an electric circuit analogue of nonlinear pendulum? To model the equation $y''=sin(y) $. They did this on analog computers in the past, how? How to model sine-nonlinearity?
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43 views

What is capacitance, in general?

In circuit analysis software capacitance can be measured between any two nodes of a circuit or of a multiterminal device. In practical terms we take $C_{ij}$, the capacitance between $i$ and $j$ as ...
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37 views

What are the first couple terms of the Taylor series for the evolution of this network of capacitors and resistors?

note: This is a computational problem, and I only need approximate accuracy, so the overall goal is, for a given accuracy and $\Delta t$ to compute the state of the system at $t+\Delta t$ to within ...
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49 views

Internal resistance of a battery

It is my understanding that internal resistance of the battery is mainly due to resistance of its electrodes and electrolytes. During the charge or discharge of the battery, there's a potential drop ...
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41 views

Coupling of LC circuits

I am reading an old article in a physics journal in which the author explains that the frequency between two identical, but capacitively coupled oscillators becomes ...
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24 views

How can the response at the terminal end of an infinite ladder network be solved?

In a recent post: How can the transfer function of an infinite ladder network be used to solve real world problems? I reference how one can solve the transfer function (impedance) of an infinite ...
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28 views

If a heater was turned on its' own wire, would heating of the wire cause the resistance to increase, thus the current into the heater to decrease?

I'm thinking not, because; A) It wouldn't make much sense in the real world because you'd need to avoid ever turning a heater towards its own wire, and you'd have to regulate the temperatures of any ...
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20 views

energy conservation in an electric circuit

Define a reactive (lossless) and reciprocal two-port by its impedance matrix $[Z]$, so that $[Z]+[\bar Z] = [0]$ and let the source impedance and open circuit source voltage be $Z_s$ and $V_s$ at ...
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42 views

On resonance of an RLC circuit

How do I prove that the width of resonance in an RLC circuit is the inverse of the proper time of the circuit? I know that the amplitude of charge in the condensator is ...
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36 views

Why can xenon gas stay ionised after the “trigger voltage” is removed?

From my understanding of a Xenon flash circuit, a storage capacitor and a trigger capacitor are charged up to about 240V (both with similar RC values, but less capacitance is needed for the trigger ...
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91 views

Ampere's law and magnetic circuit

For magnetic circuit there is an equation NI=HL. This equation is obtained by applying Ampere's law. H is magnetic field intensity and L is the length of the circuit. In following picture the equation ...
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69 views

Is shaking a phone enough energy to charge a smartphone?

Is shaking a phone enough energy to charge a smartphone? For example I'd like to use some kind of power generator to charge smartphone's battery but I'm wondering if shaking (by hand, or motion when ...
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47 views

Origin of chaos in Chua's circuit

I am doing a project on Chua's circuit, but I can't seem to find anything that explains where the chaotic nature of the system comes from. Does anyone know of articles that explain it well on an ...
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62 views

Wave velocity (R)LC circuits.

I'm attempting to simulate some fluid like mechanics using circuits. Specifically wave propagation. I am attempting to measure the wave propagation velocity using an oscilloscope on the circuit below, ...
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490 views

Energy of RLC circuit

If you are given a general differential equation for an RLC circuit, for example, $$L\left(\frac{d^2 Q}{dt^2}\right) + R\left(\frac{dQ}{dt}\right) + \frac QC = V\cos(\omega t),$$ which is a driven ...
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55 views

To find the center of charge in current waveform

I have a circuit for which output current waveform has both positive and negative points. Now I want to get a center of the charge for this waveform (means where my net charge is concentrated ?). Is ...
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54 views

Questions (intuitive) about circuits and the flow of electrons

Why don't electrons accelerate in a circuit? If there is a potential difference and the electron moves in the circuit a force is exerted on it. Why does that force produce no acceleration, keeping the ...
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140 views

Voltage in a lossless transmission line

I have a question where I'm deriving expressions for different variables within a lossless transmission line. Here's the question as posed: Consider a lossless transmission line of characteristic ...
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199 views

Different phase in capacitively coupled RLC circuits

I was trying to work with some data for a lab report I'm writing about capacitively coupled RLC circuits. The setup is pretty simple and looks like that: Where $C^{'}$ is the coupling capacitance. ...
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168 views

How is derived the relation between capacitances when a $Y-\Delta$ transformation is applied in a capacitors network?

A $Y-\Delta$ transformation can be applied to circuits in order to make an equivalent circuit (but simpler to put in terms of series/parallel devices). Wikipedia and other books show how to deduce the ...
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92 views

How power affects heating of a coil

So I am doing a little research on my own about electronic cigarettes. Most Ecig users value high power at a standard current. This means they buy very expensive, high voltage batteries and put high ...
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110 views

How to size an electromagnet

How can I size an electromagnet? For example if I would to attract a mass of $x$ kg what are the calculations that I must do to size the ferromagnetic core and of course the solenoid? And thus, how ...
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234 views

Braess's Paradox in Electrical Circuits

According to this and other similar papers, http://www.nature.com/nature/journal/v352/n6337/abs/352699a0.html, adding a current-carrying path can increase the voltage drop across a circuit. What is ...
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422 views

Algorithmic approach for applying Kirchhoff's Rules to circuit analysis

Working with Kirchhoff's rules, I am attempting to device an algorithmic approach to finding the unknowns of the problems, I am of a Computer Science background and I am finding it difficult to ...
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3 views

Ohm's law experiment

I was going through my physics laboratory manual. In the Ohm's Law Experiment, the book states a few precautions without any reasoning. 1.The wire whose resistance has to be determined should ...
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27 views

How to figure out if an element in a circuit is absorbing or delivering power?

. Eg: In the above circuit. 50v source and 0.2Va current source is said to absorb power.If power is absorbed,what work is done with the absorbed power.
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20 views

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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22 views

How do the voltage rises balance with the voltage drops in this example of a series circuit?

Consider a resistor and a capacitor in series, with the capacitor initially charged. There is a conservative electric field in the circuit, so $$\oint \vec{E}\dot{}d\vec{l}=0,$$ which gives $$\int_a^b ...
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27 views

References on Josephson ring modulators

I would like some good references on Josephson junctions and, in particular, Josephson ring modulators. I know that Devoret has written a handful of papers and notes on JJs, but I am hoping to find ...
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33 views

Diode's volt-ampere characteristics

The Problem is that If the reverse saturation current is $10\ \text{nA}$ ($1\ \text{nA}=10^{-9}\ \text{A}$), Calculate the forward current while the forward voltage is $0.6\ \text{V}$. And explain ...
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15 views

Analogy in combination of batteries in series and pn junction diode circuit to find potential difference

Can I use the analogy of combination of two batteries to get the potential difference between two points in case a pn junction diode is used in the case of other battery? In doing so what is the basic ...
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29 views

Circuit with three capacitors

A potential difference of V = 38.0 V is applied across a circuit with capacitances C1 = 4.1 nF, C2 = 4.7 nF, and C3= 2.3 nF, as shown in the figure. What is the magnitude and sign of q3l, the ...
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21 views

Resistance used to get maximum illumination with proper security

In which way a resistance is to be connected with a bulb labelled 120V-60W when it is connected with 220V DC source so that maximum illumination with proper security is maintained? What is the ...
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22 views

For series LCR oscillations (resonance), why does current have to be maximum?

I learned about a year back that systems will go into oscillations with high amplitudes if the frequency of the forced oscillations coincide with the natural frequency of the system leading to ...
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21 views

E field inside wires during transient state

I've come across an instructive paper which explains qualitatively what happens inside wires of a simple circuit during the transient state, leading to the steady state where there is an uniform E ...
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20 views

Setting up current directions in multiloop circuits with more than one battery

I'm currently working on this problem: I must find the current in each battery. I have certain doubts when estipulating the currents: How many $i$ exists in this problem? The current going in a ...
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42 views

Current through moving bar on rails with non-constant magnetic field

I am working on the problem pictured below and I cannot figure it out. I have been using the equation d[flux]/dt = -BLv and V = -d[flux]/dt. However, since the magnetic field is not constant through ...
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44 views

Physical intuition behind the fact that current in an inductor lags behind the emf/voltage by $\frac{\pi}{2}$ in an AC circuit

What exactly is the reason that current through an inductor in an AC circuit acquires maximum value after quarter a time period ($\frac{T}{4}$) of the emf getting the max value?
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43 views

Is there a way to draw a thermodynamic diagram analogous to an electrical schematic for simple ideal systems?

I have a small system in air (which should be part of the schematic), consisting of several cylinders within one another and contacting ideally at various spots. How do I model it as if it were an ...
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18 views

Is there a difference between a ground pin and voltage by an ungrounded plug and just a grouned plug?

I have a cortex dj mixer with an ungrounded plug but with a ground pin (that I don't use for now). But I get a lot of noise if a connect my speakers to this mixer, so maybe I need to ground this ...
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37 views

Energy conservation applied to a generator

If a turbine runs with a kinetic energy of some joules, the electricity produced must also have the same power given out, according to the energy conservation law. Now if the electric flux is ...
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41 views

Why does this electrometer works?

I was looking at this electrometer (measure of static field E). The principle is : E moves electrons between the 2 electrodes into the coil and there is a magnetometer inside the coil. This ...
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110 views

Loaded Quality Factor

I came up with an expression for the reflected power of a resonator: $$\left| \Gamma \right|^2 = 1 - \frac{1-\left(\frac{\kappa - 1}{\kappa + 1}\right)^2}{1 + 4 \left( \frac{Q_U}{(\kappa + 1)} ...
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35 views

Physical interpretation of Convolution

Let us say that we are interested in finding the voltage (potential difference) $y$ across the resistor. The circuit consists of a battery, a resistor and an inductor. The problem can be solved by ...
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55 views

Is this the reason why a circuit with no components (except wire) would discharge the battery faster?

I read that if I simply connect two ends of a battery it would discharge really quick and it would last longer if the circuit contained e.g. a light bulb. I wondered why is this happening and my ...