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

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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
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5answers
7k 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 ...
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2answers
748 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 ...
7
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1answer
382 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 ...
-1
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1answer
48 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
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1answer
106 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
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2answers
227 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
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1answer
5k 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 ...
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5answers
492 views

Ohm's Law Intuition

When we derive Ohm's Law using the Drude Model, we assume at one point of time that $E=V/L$, when is fact, $E=dV/dL$, unless $E$ is constant, in which case the assumption $E=V/L$ is true. But I don't ...
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0answers
57 views

The mathematical physics of saltatory neuron action potential transmission

Some time ago, I tried to understand saltatory electrical potential transmission on a myelinated axon but have not found a clear mathematical model of this mechanism. I understand the cable theory, ...
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3answers
4k views

Questions about voltage

For some reason, I feel like the concept of voltage is escaping my grasp. I've done much research on these forums and through texts, and come across answers that seem quite well thought out, but still ...
1
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0answers
32 views

ODE envolving current [closed]

I have to do this exercise: 9. The current $I(t)$ at time $t$ flowing in an electric circuit obeys the differential equation $$I''(t) + RI'(t) + I(t) = \sin \omega t$$ where $R$ and ...
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2answers
79 views

How to calculate the charge on a capacitor [closed]

I have a network in which $C_1$ ($8.73 \;\rm \mu F$) and $C_2$ ($2.46 \;\rm \mu F$) are connected in parallel and $C_3$ ($7.45 \;\rm \mu F$) and $C_4$ ($2.22 \;\rm \mu F$) are connected in parallel. ...
2
votes
2answers
561 views

How does AC current flow in an open circuit?

In common house hold wiring we have the hot lead, neutral and ground. If the hot lead in electrical wiring contacts earth ground (perhaps though a short circuit in the chassis of a device) then the ...
0
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3answers
91 views

Alternating Current Inquires [duplicate]

I have been looking in to alternating current and I am confused. If the voltage reverses doesn't the flow of electrons also reverse? I am aware of another fair answer on this site here. That answer, ...
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2answers
152 views

What is the theoretical/intutive meaning of $x(t) = x_0 \cos ( \omega t + f )$?

What is the meaning of $x(t)=x_0 \cos(\omega t+f)$, where $x_0$ is the amplitude, $\omega$ the angular frequency, $t$ time and $f$ the phase constant? I know how to solve the mathematical problems ...
0
votes
1answer
126 views

Simple Parallel Electric Circuit [closed]

Ammeter (A1) and voltmeter (V) in series have parallel connection to another ammeter (A2). Currents in A1 and A2 are respectively 0.2 and 1.7 amp. Voltmeter's voltage is 6 volts. How should I find ...
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1answer
101 views

Why is parasitic capacitance in inductor said to be in parallel?

Internal resistance of inductance (or other devices) are said to be in series. But parasitic capacitance is said to be in parallel (in case of an inductor). Why is that so? What determines whether an ...
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2answers
118 views

$R = dV/dI$ for varying temperature

I'm trying to do my prelab for an E&M course, and am asked if, for plotting $V$ vs $I$ with a varying temperature, I should expect a linear slope. I know that both $V$ and $I$ depend on $R$, and ...
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3answers
94 views

Could this open electric circuit work?

Two batteries are interfaced by a resistor. Parameters such as resistance can be set arbitrarily. Does it work?
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1answer
74 views

How to measure area under the waveform (electric current)?

I have a current waveform from my circuit which goes up and down the x-axis. x-axis represents time and my y axis represents current. How should I calculate total area under the curve? Should I take ...
1
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3answers
135 views

Why would we need to ground an AC source

I'm new to this field hence this weird question. Why would we need to ground an AC source? Why wouldn't it be enough to have just one pole to get an AC current going? I understand why it wouldn't work ...
0
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1answer
449 views

The Voltage and Current of a Discharged Inductor at the Instant the Switch is Closed

The figure shows an LR circuit with a switch and a 240-volt battery. At the instant the switch is closed the current in the circuit and the potential difference between points a and b, Vab, are ...
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0answers
45 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 ...
2
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1answer
186 views

Finding the electric field around an electric eel

I'm having problems solving for the electric field and the current that an electric eel generates. Would I use Gauss's law and treat it as a long charged wire? How would I find the charge of the ...
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1answer
143 views

Why is $I_0\sin\left(\dfrac{\pi}{2}-\omega t\right)$ not used as a solution of the purely capacitive AC circuit?

Why is $I_0\sin\left(\dfrac{\pi}{2}-\omega t\right)$ not used as a solution of the purely capacitive circuit? My Research I've searched on Google, Phys.SE and many school level Physics books ...
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1answer
226 views

Choosing sign for KVL (mutual inductance)

If I am writing KVL for one loop of the circuit which contains a coil coupled with another coil from another loop, the sign is chosen considering whether both currents enter or leave the stars AND if ...
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3answers
10k views

Two 60W-lightbulbs are connected on 220 V AC-voltage - how much electric power is spent by each lightbulb? [closed]

Two 60W-lightbulbs are connected on 220 V AC-voltage - how much electric power is spent by each lightbulb? There are two scenarios: In one, these two lighbulbs are connected serially, and in the ...
2
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2answers
50 views

electric-circuits

Why can't you connect the + of a device to one battery and the - to another battery (and have it work)?
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2answers
145 views

Dimension of the space of solutions in an electric circuit

Consider an electric circuit with dc sources ( voltage and current) and resistors. Write down the equations. In the most general case, the solution of the system is not unique. The set of solutions ...
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0answers
31 views

Replacing diode in circuit analysis?

While analyzing circuits containing diodes in reverse bias I replace it with a pure insulator for simplifying things. Similarly can I replace a forward biased diode with a conductor and a varying ...
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3answers
465 views

Why are exothermic reactions easier than endothermic?

If we talk about electric heating then we have simple elements in which we apply electrical energy which gets converted into the kinetic energy of the electrons which heats it up. But while cooling, ...
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1answer
160 views

The effects of reversing the leads of an ammeter

I was playing around with a battery, an ammeter, and a light bulb. The ammeter originally read 1.99 A, but after reversing the leads going into and out of the ammeter the ammeter read -1.98A. I know ...
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0answers
55 views

Circuit analysis, calculating voltage across resistor [duplicate]

i'm solved this question, I'm sure that solution is right, but my instructor says that V1=116V, and also he said that he will not show how he get this result.Please help to identify who is right.
2
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3answers
3k views

Why does a fluorescent tube-lamp flicker before lighting up?

If you turn on a fluorescent tube-lamp, it flickers before lighting up. If you then turn it off and turn it back on after 2 seconds, this time it doesn't flicker but lights up straight away. If you ...
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3answers
256 views

Capacitance: How to increase total charge drawn from a battery?

I can't seem to find any information about how parallel capacitors or capacitors in a series affect how much a capacitor can charge, not in my textbook or online. Here is the question I am trying to ...
0
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2answers
1k views

What do we mean exactly by the positive/negative charges in cathode and anode?

In batteries, what exactly do we mean by negative and positive charges? My understanding is that the negative charge of the anode is basically an atom with an extra electron in the last orbital and a ...
22
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3answers
5k views

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 ...
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1answer
58 views
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964 views

How does mass relate to resistance (Ohm's Law)

How can I relate $mg$ to $R$? Just to give you a scenario: If a free hanging weight was tied to a motor... I know the voltage ($V$) and current ($I$) so I can use $V = IR$ to find $R$. What if I ...
3
votes
2answers
892 views

What is the physical interpretation of the Fourier transform $(\mathcal{F}Z)(t)$ an impedance?

If I compose a impedances out of smaller ones in series and parallel configurations, e.g. $$Z(\omega)=i\omega L_2+\tfrac{1}{\tfrac{1}{R_1}\ +\ i\omega C_1+\ \tfrac{1}{i\omega L_2}},$$ then I get a ...
0
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1answer
119 views

Why are diodes able to amplify signals in groups, but not alone?

Single diodes can determine whether a signal passes or not (depending on the biased)(plus they can even rectify a signal), yet why does it take a combination of diodes(like a transistor) to amplify a ...
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4answers
1k views

Is voltage important when creating a magnetic field?

Would a DC circuit that has a high current and low voltage have a powerful magnetic field? I'm trying to create a powerful solenoid. In order to create a powerful magnetic field, I'm focusing more on ...
4
votes
1answer
70 views

Why is Kirchoff's Current Rule valid?

The fact that Kirchoff's Current Rule is valid means that whatever current flows in flows out. But this will only be valid for a steady current circuit, that is, when there is no accumulation of ...
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0answers
51 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 ...
2
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2answers
157 views

What does E/M field look like when I close a circuit?

Suppose that we have a charged capacitor with two pins: $ C_+ $ and $C_-$. Suppose that we have a long wire with fixed geometry, that is already connected to the pin C+. Let the ...
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5answers
4k views

Does current flow back to the source through earth?

We know that if Single Line to Fault occurs, then fault current flows to the earth. I want to know whether the current will return to the source or not. For the current to flow we need a closed path. ...
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4answers
7k views

Detecting if resistances are parallel or series in complex circuits

I know how to detect when resistors are arranged in parallel or series arrangement and I can also find their equivalent resistance in simple circuits or when resistances are connected in form of ...
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1answer
518 views

How to calculate a charge of capacitors on a circuit (both paraller and serial)

I have a circuit with capacitors on it: I am trying to figure out the charge on each capacitor. The following is given: i know that parallel capacitors follow the equation and that ...