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

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2
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2answers
52 views

According to calculations why the current of a battery of a mobile is high?

If you pay attention to the features of your mobile's battery the voltage would be around 3-4V and power is 4-5 Wh (14400-18000 Ws) and with calculating the current you can find a very high ...
1
vote
0answers
40 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 ...
0
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1answer
25 views

Electricity parallel combination

Why is resistance lower in a parallel configuration and therefore current is more? Shouldn't resistance be addition of all resistor's resistance?
-1
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3answers
52 views

Electricity series connection of resistor

In simple circuit is current in wire different from current in resistor as wire also opposes the flow of electrons so wire should also be added in series connection of resistor
0
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3answers
73 views

What is the voltage at every pair of points along a ideal wire that is connecting the two terminals of a battery?

If you stick a wire across a battery, obviously it is going to discharge the battery. This will be due to a voltage difference between the two terminals. However, the equation $V = IR$ tells you how ...
0
votes
2answers
58 views

How long do electrons take to “decide” how to go through a circuit?

Many other people have asked how an electron decides which path to take, but no one has asked how long do they take. Is there an equation for their "uncertainty" time? Do they decide instantaneously ...
3
votes
1answer
48 views

Does an Inductor maintain it's energy?

Consider a simple LCR ac circuit; generally I (might) understand that the charge exchange between capacitor and inductor would induce a harmonic current flow, but I remain confused for two reasons: ...
-1
votes
1answer
147 views

Resistor cube problem solving method

I was solving problems from Irodov when I came across the method called point of symmetry method. I cant find this method anywhere. So what is this method? Here is the link to the problem solution ...
0
votes
1answer
28 views

can a power supply with high voltage value and some current be split into multiple small voltages of same current?

For example: if I have a source that can give an output of 10,000 Volts with some unknown current value, now, can i make that 10,000 Volts to 50 (need not be 50 exactly but maybe more than 30) of 200 ...
0
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2answers
51 views

What happens to half of the energy in a circuit with a capacitor?

For a simple circuit with a battery supplying a voltage V to a capacitor, let us assume that the charge on the capacitor is Q. Now, the work done by the battery or the energy supplied is given by the ...
0
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0answers
30 views

Occurance and disappearance of degeneneracies in a periodic structure of (quantum) LC circuits

Introductory part I'm currently studying an analytical model of coupled LC circuits, in preparation for actually performing measurements on such structures. While the final goal will struggle with a ...
1
vote
2answers
51 views

Why does electrical impedance have as many parameters as it has?

The impedance of a circuit is written: $$ Z(R,L,C,f) = R + j ( 2 \pi f L - \frac{1}{2 \pi f C} ). $$ What is the line of thinking that frequency, resistance, capacitance, and inductance are the only ...
-1
votes
3answers
42 views

Effect on capacitance when capacitor number increased [closed]

What happens to total charge and potential difference when number of capacitors increased in series and parallel combination? My question in text book is: Initially, a single capacitance $C_1$ is ...
1
vote
2answers
41 views

Quality Factor in a Parallel LC Circuit

I was wondering if there is a notion of a quality factor in a parallel LC circuit, since there is no resistance. One can show that this circuit has a resonance frequency as follows: Impedance: ...
0
votes
1answer
31 views

AC pass through capacitor

I am confused how AC pass through a capacitor? Can any one explain or have the vedio how AC pass through capacitor?
0
votes
0answers
32 views

What exactly happens in an electric circuit?

After reading chapters on Electrostatics, I have been having lots of problems in understanding current electricity.I will be trying to tell what my problems are by telling what I already know.Please ...
0
votes
1answer
65 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 ...
0
votes
0answers
26 views

Initial current, RC Circuit

The task goes like this: The voltage between the points A and B, in the circuit diagram below, is 100 V. What's the initial current through the resistor when we close the switch S? (Other components - ...
-1
votes
3answers
98 views

Why does the resistance halve when two resistors of equal resistance are in parallel? [closed]

This is the question and answer to a homework question and I do not understand why this is the case. What is the logic behind it?
0
votes
1answer
53 views

Equivalent Resistance [duplicate]

I've never had problems in finding the $R_{eq}$ of a circuit, but in this case I don't really know how to do it:
0
votes
1answer
67 views

Confusion with potential difference [closed]

I was trying to solve a hard problem involving a circuit like this: Find the reading on the voltmeter (red ones are resistors) I don't know how to think about potential difference across branches ...
0
votes
2answers
66 views

Calculating the energy supplied by a battery

If you wanted to calculate the energy supplied by a battery in time $t$ you would use $E=VIt$ where $I$ is the current through the battery. If the internal resistance is $r$ we could also use ...
1
vote
1answer
48 views

Calculating resistances in parallel

I was playing around with a question involving resistances in parallel. I realized that $n$ equal resistors (resistance $R$) in parallel have combined resistance $R/n$. I proved this using ...
1
vote
2answers
52 views

Resistors in parallel: How do I make this rigorous? [closed]

In my revision guide it says "when two resistors are in parallel, the current has two paths it can flow through so there is less opposition to the current. This is why the combined resistance is less ...
2
votes
1answer
19 views

Need help understanding appliance ratings

I keep coming across things like "A filament lamp rated 12 V, 1.0 A", or "a heating element rated 230V, 500W". I think the first one is saying that a 12V potential difference across it will make a ...
0
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1answer
45 views

Experiment for finding resistivity

I was reading an experiment to measure the resistivity of a wire. I understand everything except for why the variable resistor is connected to the side of the positive terminal of the battery. Since ...
0
votes
1answer
44 views

Difficulty understanding electricity concepts

In circuit diagrams what does it mean for energy to be used in going through a component? I usually see this when emf is being described: total energy supplied per coulomb by battery = total energy ...
1
vote
0answers
44 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 ...
1
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1answer
46 views

What happens here in this capacitor?

What happens when we earth the circuit as shown below, why should it matter? because potential at a point is relative? So if the earlier potential was $V_p$ at that point, it becomes $0$, so every ...
4
votes
1answer
63 views

Why an inductor parallel with a light bulb makes it flash as a key closes the circuit?

The title is a simplified form of my question. To be precise, I'm talking about the following circuit: The inductor has a resistanse equal to the resistor in the circuit. So, the question is that, ...
1
vote
2answers
57 views

What is the rigorous definition for current in a closed circuit?

I know that $I = \frac {dq} {dt}$, but I have trouble reconciling that derivative definition with my intuitive understanding of current. At an arbitrary point in wire, the current is obviously the ...
1
vote
2answers
69 views

Voltmeter in series with a component?

I always see voltmeters connected in parallel with a component, but what happens if you connect it in series? I think it's due to the high resistance of a voltmeter but I don't really see why this ...
-3
votes
1answer
616 views

What would be the resistance of a wire, if it is stretched to double length? [closed]

If there is a wire of resistance $R$ and we stretch it such that it becomes 2 times longer, then what should be the new resistance of the wire?
2
votes
1answer
105 views

Circuit analysis (Kirchoff's laws) for multi terminal resistors

Consider a four terminal resistor as shown here There exists a matrix resistance equation of the form $V_i=R_{ij}I_j$ for some $4\times 4$ matrix $R$ for each such four terminal resistor. I want to ...
1
vote
3answers
82 views

Deriving ODE for voltage across capacitor-RC circuit [closed]

I need to derive an ODE for the voltage across the capacitor in a specific RC circuit. The circuit has 1 resistor, one input, one capacitor and a switch. So far I have $$\frac{dv}{dt} ...
0
votes
1answer
32 views

How long can a cellphone battery(pictured) power a LED light that produces light equivalent to traditional 60W bulb(800 lumens)?

Assuming Energy Star rated LEDs which produces 100 lumens/watts. Battery rated as 9.88Wh. Power consumption by LED = 800 lumens/100lumens/watt = 8 Watts Does it mean that it will power circuit for ...
1
vote
1answer
110 views

Calculating half power frequency (frequency response)

I am having a doubt in calculating half power frequency for a given RLC AC circuit. I have attached images of two questions with their solutions. In the first question, the equation for ...
0
votes
1answer
51 views

Cryptic remark in physics revision guide

I am currently revising for my AP physics and I couldn't understand one of the end-of-section summary notes. It says: "Remember that the direction of magnetic field is from North to South, and that ...
0
votes
1answer
36 views

Diodes in AC current

If in AC current, the direction of the current is always changing, then if one was to place a diode (for simplicities sake lets say an LED) in an AC current, would it flash to the frequency of the ...
1
vote
1answer
48 views

Typo in physics book (capacitors)

I'm currently working through an AP revision guide. The section on charging a capacitor outlines the following steps: When a capacitor is connected to a battery, a current flows in the circuit until ...
-1
votes
1answer
45 views

Faraday's Law: Current loop and proton

A single circular loop of wire with radius R carries a large clockwise current I(loop)=I0, which constrains a proton of mass M and charge e to travel in a small circle of radius r at constant speed ...
0
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1answer
95 views

Question on an unbalanced Wheatstone bridge

Let, P/Q = R/S in the usual sense of a Wheatstone bridge where PQRS are resistances. Then we know that the potential between midpoints of PQ and RS are equal and there's no potential difference ...
12
votes
5answers
2k views

Is current in superconductors infinite? If they have 0 resistance then I (V/R) should be infinite? [duplicate]

I learned many years ago that according to Ohm's law, current is equal to voltage divided by resistance. Now if superconductors have zero resistance then the current should be infinite. Moreover the ...
1
vote
1answer
38 views

Why doesn't the electric potential constantly decrease in a circuit as the current moves from the positive to the negative terminal?

Why doesn't the electric potential constantly decrease in a circuit as the current moves from the positive to the negative terminal? Details and Assumptions: 1. The wires show no resistance.
0
votes
0answers
44 views

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 ...
0
votes
0answers
37 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 ...
2
votes
1answer
37 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 ...
0
votes
1answer
26 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 ...
1
vote
0answers
33 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 ...
0
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1answer
53 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, ...