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

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If I lick a 9V battery, why doesn't my tongue noticeably get hotter?

Power dissipated is I^2*R, I don't know the resistance of my tongue so I can't tell how much current goes through my tongue. A resistor I have does get hot and I'm guessing it has a higher resistance ...
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1answer
64 views

Reference for Kirchhoff's Circuit Laws

Does anyone know the reference where Gustav Kirchhoff published his famous circuit laws?
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1answer
10k views

What defines the brightness of a bulb?

So I have a question. There are three identical bulbs, 2 of them are connected in parallel and the third is basically in series, on the same circuit. If the one of the lamps in parallel breaks, what ...
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0answers
30 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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2answers
22 views

Determine the size of a conductive medium

Are there any measurable characteristics that would allow one to discern the size of a conductive medium? Say I apply the same voltage to a two foot long wire and a four foot long wire. Is there ...
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1answer
52 views

Thevenin theorem

Hi i got the trouble and i miss the concept about v out in thevenin i have the circuit like this so i used voltage divider for finding the voltage at point 1, but how to finding voltage at Vo , ...
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4answers
338 views

Ohmic Heating in Wires

please could someone tell me why Ohmic losses are always referred to as $I^2 R$ losses? Here is my problem. If the power coming from a power station is fixed then you can either deliver this power as ...
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1answer
1k views

Significance of Time constants in LR and RC circuits [closed]

What is the significance of a time constant in a circuit? Is there any use of knowing the time at which the charge in a capacitor is 1-1/e times its total charge? What is special about the capacitor ...
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42 views

How soon would electrons start flowing once I closed a switch on a circuit that was one light minute away from the battery

In a circuit, how do electrons "know" when the circuit is closed? To my understanding, they do not start flowing unless the circuit is closed. How soon would they start flowing once I closed a ...
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0answers
101 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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1answer
69 views

How big of a capacitor would I need to release 5 amps for 0.2 seconds? [closed]

Just what the title says, 5 amps for 0.2 seconds. Please bear in mind that I have absolutely no grasp on electrical wiring, so I would appreciate simple terms. What I need to do is release a burst of ...
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58 views

Voltage Circuit

I feel that I don't understand how voltage works in a circuit. I understand voltage to be electric potential energy per unit charge (kq/r). In the case of a circuit, electrons flow from low potential ...
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1answer
69 views

How do i interpret the following electric potential diagrams?

We recently started to learn about electricity in school and I'm trying to understand the concept of voltage(potential differance). From what i understand, electrons flow from the negative terminal to ...
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1answer
54 views

Deriving Loop Equations in a Circuit with 2 batteries?

First time posting here, so please help with formatting. I need help deriving loop equations for this becaue the 2 batteries/power supplies are throwing me off. https://i.imgur.com/MJH6mIM.jpg The ...
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1answer
63 views

What is voltage in a circuit?

What is voltage in a circuit? We just started learning about electricity in my school. From what I understand; potential is potential energy per Coulomb and voltage means difference in potential. So, ...
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2answers
9k views

Electron flow and electric potential

In the physics tutorial topic on current electricity it defines the positive terminal as the high potential terminal and the negative as the low potential. When talking about positive test charges ...
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1answer
88 views

Given a large, multiloop circuit with resistors and batteries and I'm not sure how to simplify it. (When NOT to combine resistors?) [closed]

So here's the circuit, and the question is looking for current i: All resistors are 2 ohms and the batteries are 5 volts. I'm trying to apply the resistance combination Kurchov rules to make this ...
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0answers
24 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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0answers
72 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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2answers
176 views

Inductive reactance 0 for dc current?

Inductive reactance: $$X_L=\omega L=2\pi f L$$ is the opposition to the flow of current by an inductor. Frequency $f$ being $0$ for a DC current, the inductive reactance too is $0$. But doesn't the ...
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2answers
122 views

Is this circuit a series or parallel circuit?

I saw a definition of a parallel circuit as a circuit with more than one path for current to flow. Is that the definition that's accepted? It seems like a good definition to me, but does that mean ...
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1answer
97 views

Finding the resistance of platinum wire [closed]

Im currently lost on solving this potentially simple electricty question and was wondering if anyone in this community could hint me or tell me which equations and why these equations would be ...
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3answers
21k views

Why do current-carrying wires heat up?

Obviously wires heat up too, but why do they heat up? And for the same reason, why do we get electrical burns?
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59 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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1answer
43 views
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2answers
418 views

Why does all the current flow through a short circuit if its voltage drop is considered zero?

Path of least resistance vs. short circuit I know the path of least reisistance has been clarified already However, to derive the equations you need to assume that the voltage of each parallel ...
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1answer
42 views

magnetising the material using coil

I studied that when alternating current is passed through the coil ,the coil produce magnetic field (primary) as shown in figure,when any conducting material placed near to that field, eddy current ...
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3answers
9k views

What happens if I throw a battery into water?

Today I have by accident thrown a AAA battery into a bucket of water. I fished it out of the water immediately (within 20 seconds or so) and nothing notable had happened and the battery is still full ...
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2k views

Why doesn't the electric field inside a wire in a circuit fall off with distance from the battery?

We studied electric fields due to point charges. The magnitude of these fields decreases with the square of the distance from the point charge. It seems to me that we could treat the positive ...
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1answer
121 views

Must a universal motor always rotate at the frequency of the AC current?

So here I have a picture of a motor (I think it is a universal motor but I am not sure). My question is if this motor is connected to an A.C. supply, does it have to rotate at the frequency of the A.C....
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2answers
66 views

Parallel resistances

How is the net resistance lesser than the least resistance when resistances are connected in parallel? The electrons will have to flow through one of the resistances, right? To me, it seems like the ...
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2answers
40 views

Filament lamp $(V,i)$ behavior between 0 and 1V

I was wondering why the behavior is more "chaotic" at 0~1V when compared to 2V+ (which is when it starts to glow).
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0answers
77 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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2answers
108 views

Why is an $LC$ oscillator lossless, but $C V^2 / 2$ energy is lost to a capacitor connected to an ideal voltage source?

It is mathematically proven that in an $LC$ oscillation that all the energy gets transferred from the inductor to the capacitor and vice versa. There is no energy loss as there is no load in the ...
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0answers
31 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 mixer....
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56 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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3answers
1k 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?
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1answer
51 views

What holds good? [closed]

If the 1 ohm resistor is replaced by a 0.2 ohm resistor. what will be the current flowing through ? What actually determines it ? the OHM'S LAW or POWER CONSERVATION ?
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2answers
2k views

What's the difference between a positive and a negative current?

Say I have a wire, and I connect a current source on its left end, and a ground to its right end. Then using my power supply I source a positive current, does this mean that electrons will move from ...
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1answer
114 views

How to solve difficult resistance puzzles? [closed]

How does one solve really difficult resistance puzzles? These are presented in the form of a diagram with multiple resistances in various combinations. I have done some puzzles by reducing the puzzle ...
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1answer
37 views

Why a capacitor's potential increase until it is equal to the potential of the battery?

I understand that the potential between the plates of the capacitor increases as the circuit runs, but why it stops increasing exactly when it becomes equal to the potential of the battery?
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1answer
26 views

Current and Heat in Circuit [closed]

Find current through the circuit. Also, find heat generated in each resistor. MY ANSWER:- In Parallel, 1/Rp = 1/12 + 1/6 = (1+2)/12 = 4/12 Rp=3 ohm Total Resistance = 4 + 4 ohms = 8 ohms Current,...
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3answers
197 views

$\vec{E}$-and $\vec{B}$-fields in RCL circuit

Consider a basic RCL-Circuit consisting of an ideal resistor, an ideal capacitor and an ideal inductor in series. Assume that at time $t = 0$ the current is zero and the capacitor is charged with ...
22
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6answers
4k views

Could someone intuitively explain to me Ohm's law?

Could someone intuitively explain to me Ohm's law? I understand what voltage is and how it is the electric potential energy and that it is the integral of the electric field strength etc. I also ...
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2answers
137 views

What does Potential Difference between a load/resistor mean?

Guys this has been bugging me for ages and all the answers i found online were unsatisfactory. My questions is, what does difference in potential or potential drop after current passes through a load/...
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3answers
558 views

How to Determine and Verify Series and Parallel

I am having a lot of trouble visually identifying which elements in a circuit are in series and parallel is there a formal mathematical way I do this with Kirchoff's Law?
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2answers
466 views

Current in Inductor and Capacitor with DC voltage source? [closed]

A DC source in series with pure Inductor and pure Capacitor no Resistance. How the current will flow in this circuit? What I just know is that in the beginning Inductor will behave as an open circuit ...
2
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6answers
250 views

Current when resistance is 0

A short circuit has $\rm 0$ resistance. We use Ohm's Law $\rm V=IR$. If $\rm R=0$, then $\rm V=0$. Doesn't this mean $\rm I$ can theoretically be anything? Thus $\rm I$ can be like $\rm35A$ for ...
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1answer
36 views

Detect Breaks in Mesh Circuits [closed]

PS: I will mess up a lot of terminology throughout the question. Anyways, I want to build a circuit which is in the shape of a mesh, something like a table and subsequently detect whenever there is ...