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

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What is the theoretical reasoning behind calculating emfs in series or parallel?

First off, I did some research on my own but the answers weren't satisfactory. The analogy of the water pump makes zero sense as I see no way how "Potential" is even comparable with "Dynamic ...
3
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3answers
557 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 ...
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24 views

RC Circuit Analysis

I want to correct three misunderstandings about the following RC circuit. 1) How does current move directly after switch S gets closed? Current runs through all three circuit components to begin ...
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0answers
30 views

Electric circuit question [on hold]

A 100W bulb is connected in series with a room heater.If now 100W bulb is replaced by a 40W bulb,the heater output will (Decrease) (Increase) (remain same)? And explain why?
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1answer
136 views

Are magnetic hysteresis losses relevant to alternating currents flowing in a wire?

Say we have an AC in a magnetically lossy material, like iron. Because of iron's relatively high permeability, skin effect will be more pronounced than it is in say, copper, so this iron wire isn't so ...
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2answers
289 views

What would happen to electronic circuits when traveling near the speed of light?

Imagine a space ship, loaded with all sorts of computer systems, traveling near the speed of light. Electricity itself is very fast, and can reach speeds close the speed of light. (up to 99% ...
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0answers
36 views

Find resistance of inductor in series RLC circuit [on hold]

We have a resistance of 350 Ohm, an inductor of 0.15H and a capacitor of 10 microfarad, connected in series to an AC source of voltage 240 V and frequency 50 Hz. The measured effective voltage over ...
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0answers
30 views

Fastest converging series of resistors

I am looking for a recursive circuit which grows very fast and has a finite resistance but an infinite number of resistors. I have found many ways to get a finite given resistance with an infinite ...
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1answer
29 views

How can I physically demonstrate potential difference in a circuit to a 14 year old?

Children of this age have a fair idea about current, resistance, and batteries. Potential difference is a thing that cannot be felt or physically visualized. A teenager asked me if he can touch ...
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0answers
23 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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6answers
15k views

Power dissipated in series versus in parallel

Do two resistors in parallel dissipate more heat per unit time for an applied voltage when compared to two resistors in series?
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1answer
22 views

Circuit with inductor

How would I find the current through each resistor/inductor as a function of time? I am lost conceptually here. (I made these numbers up, so they may not be "pretty" if/when taking equivalent ...
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1answer
26 views

How can I rearrange an equation to find a gradient for a capacitor?

If I plot R on the x axis and T on the y axis to give a straight line graph, and I am given that $V$ = $V_0$ * e^(-t/RC) then how can I prove that the gradient of the graph is equivalent to $C$ * ln3, ...
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0answers
17 views

What does an electrical circuit failure mean? [closed]

When does an electric circuit fail or break ? I thought it is due to the flow of excess current or when no current flows. Is my view correct ? I also need details about electrical circuit failure ...
2
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3answers
207 views

Finding current in the circuit

Hi anyone. I try to de-draw the circuit in the simpler to calculate i1 and i2. But can not. Anyone have any hint to do this question ? . Or just give me the specific name of the way of how to do ...
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1answer
161 views

Finding the voltage of the circuit?

Capacitor 3 in Figure (a) is a variable capacitor (its capacitance C3 can be varied). Figure (b) gives the electric potential V1 across capacitor 1 versus C3. The horizontal scale is set by C3s = 20 ...
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2answers
55 views

Homework: electrical circuit with 2 voltage sources & 1 switch

I can't figure out how to handle this circuit. I am asked to calculate the total resistance and the current over each resistance (R1-R4) when the switch is open. However I'm not getting anywhere ...
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1answer
794 views

Capacitor charging, work done by battery on changing polarity

A uncharged capacitor $C$ is connected to a battery with potential $V$. It becomes fully charged and has a charge $Q=CV$ stored on it. Now the polarity of the battery is reversed. The capacitor will ...
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0answers
10 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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0answers
38 views

Does earth conduct electricity?

if we connected a voltage source with its two terminals in the earth does it conduct electricity ? and why they use something like " ground or earth " in safety to let the residual charges go to the ...
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0answers
5 views

Why is the voltage drop across this transistor the full voltage of the battery? [migrated]

I am currently learning about transistors from allaboutcircuits.com. He presented the following schematic: He claims that when the transistor is in its cutoff state, V.output will read the full ...
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3answers
91 views

Induction on a circuit with switch

I have the following circuit: It is subject to a steady, time-invariant magnetic field which points out of the paper. At $t = 0$, the switch closes. I thought that the magnetic flux would decrease ...
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0answers
24 views

How do I find the electron confinement energies in a spherical quantum dot?

So if I've got a spherical quantum dot, we'll say it has a 10nm diameter for simplicity. This dot is a semiconductor and it has an electron with an effective mass altered by a factor of 0.2. How do I ...
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1answer
163 views

What does a negative Thevenin-equivalent resistance mean?

What is the physical meaning of negative value of "Thevenin" resistance? Sometimes in the calculations, a negative value of Thevenin resistance appears.
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3answers
340 views

How do electrons actually move in a circuit?

Last year, we were taught about electricity, about how electrons move 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 ...
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4answers
72 views

Why is $R_2$ and $ R_3$ parallel with $R_1$ in this circuit?

I know that if $V_2$ wasn't there it would make sense if $R_2$ and $R_3$ were parallel with each other and in series with $R_1$. Why is it different in this case?
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15 views

How does one measure the power factor?

How does one measure the power factor? $$\text{power factor}\equiv\frac{\text{power}}{|V||I|}=\frac{R}{\sqrt{R^2+(1/\omega^2C^2)}}$$ for an RC circuit driven with $V(t)=V_0\cos{(\omega t)}$.
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1answer
65 views

Shouldn't the currents be time-continuous here?

My intuition is that the current upon an inductor (say, a solenoid) will always be time-continuous, without "sudden changes". But below is a case that seemingly contradicts this point of view. There ...
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1answer
329 views

How is the current flow perpendicular to the wire?

This answer gives a great explanation of how surface charge builds up to force the current to move perpendicular to the wire: http://physics.stackexchange.com/a/102936/41086 However, it fails to ...
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3answers
42 views

How does the voltage across an inductor and a capacitor vary in series LCR circuit about resonance?

I am aware that at resonance, the voltage across the inductor and the capacitor are equal in magnitude and opposite in phase. However, I want to know how the voltage across $L$ and $C$ vary if I vary ...
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1answer
23 views

self inductance basic example: meaning of current flow AFTER opening circuit

while studying self-inductiance, I got into a tricky point... Consider this video: https://www.youtube.com/watch?v=0IVJaXO_0XA (minute 13.00). At this moment, opening of the R-L circuit is ...
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2answers
632 views

Do the copper connectors we used in measuring the resistance of a wire contribute to the said measurement?

We measured the resistance of a wire by setting the multimeter to ohmmeter mode and connected the ends of the ohmmeter to the ends of the wire; and we also calculated the theoretical value using a ...
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2answers
37 views

Simple Circuits [closed]

I have a small and easy dilemma, judging by how sophisticated the website is, and need a simple answer for it So $P=E/t$. And $P=I*V$. Therefore $E/t=I*V$. I just need an explanation on how this is ...
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1answer
128 views

Why is there no induced electric field in the experiment (Faraday's Law)

Below are three circuit diagrams for each of Faraday's experiments that allowed Faraday to come up with Faraday's Law. In Griffiths' Introduction to Electrodynamics Griffiths states (on page 302 of ...
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1answer
52 views

Wheatstone bridge intuition - and the potential divider

I am having trouble understanding the working of a Wheatstone bridge. I am looking for an intuitive understanding of the process. Basically, I would like to have the following questions answered: ...
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2answers
68 views

Which lamp is brighter, the one through which electrons flow or current

I was thinking about problem that i don't really know the answer to. A circuit is set up with one battery and two identical lamps in series. Like so I know that electrons flow in the opposite ...
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0answers
9 views

Induced-EMF in a parallel circuit, vs a series circuit?

I wanted to know the difference between the induced-EMF in a series circuit layout, vs a parallel circuit layout. In a series the current would stay the same,however, the induced-EMF would increase? ...
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1answer
119 views

Why the EMF of a battery doesn't depend on distance between the two electrodes?

I have read that resistance of a conductor is directly proportional to its length. So, the EMF of a conductor (electrolyte of battery) should increase with increase in length/distance between the ...
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4answers
6k views

Finding equivalent resistance in complex circuit

In my previous Phys.SE question, situated here, I asked about finding the equivalent resistance of the following circuit : I got some very good answers and some tips. Now what if the same circuit is ...
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1answer
48 views

How to find the voltage?

How to find the voltage ? Given is the following mixed circuit below, every resistor has the value $1$ ohm, the current flow through the last resistor is $1$A and I have to find the voltage V ...
2
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3answers
342 views

Is equivalent resistance always lower if we add a resistor to a passive electronic circuit?

How to prove that equivalent resistance of any passive network is always lower if we add a resistor between arbitrary two nodes? Note that this is not necessarily a parallel circuit, 2 nodes that we ...
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0answers
135 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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0answers
14 views

What is Switch Contact Rating? [migrated]

If Contact Rating of switch is 5A 240V AC & 0.25A 240 DC, Then is this switch can be used for contact rating of 220V (+10, -15% voltage variation) AC & 127V (+10, -15% voltage variation)
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1answer
27 views

Power dissipation across resistors in series

Suppose we have a simple circuit with an input voltage source $V$ and two resistors. Now if we want to find the power dissipated by each resistor using the formula $V^2/R$, should the voltage be the ...
0
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1answer
15 views

According to the Kirchhoff's law, what's the ratio between currents in output branches of a node?

How the current distribute in branches of a node in a circuit? Is it randomly? Can it be zero in an output branch when all branches have ~same physical features? For example, suppose the current as ...
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1answer
34 views

Explanation for: A monopole antenna must contain a resistor (or equivalent) and therefore must have 2 terminals?

Could someone explain why this sentence makes sense: A monopole antenna transfers energy from electrical domain to the electromagnetic domain, hence must contain (equivalently) a resistor, hence ...
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2answers
117 views

Close or open circuit?

A electric source provides a non electrostatic influence on the charges inside the source which pushes the positive charges from the negative terminal to the positive one. Does this happen when the ...
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2answers
35 views

Capacitor discharging

We know that discharge a capacitor will cause the voltage of capacitor to drop with time. But how about the bleeder resistor? Will the voltage of bleeder resistor increase or remain unchanged?
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1answer
50 views
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1answer
30 views

Potential Difference between 2 points in a curcuit

3 Cells and 3 capacitors are connected as shown in the diagram. What is the potential difference between points A and B ? What are the final charges on each of the plates of the Capacitor ? Does the ...