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

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1answer
48 views

Resistor homework assignment: 7 resistors with connected triangles [closed]

I am a lost in how to solve this problem, since I don't how where to start. The questions doesn't inform any voltage or current, asking only the equivalent resistance of the circuit. All resistors ...
4
votes
4answers
2k views

The electric field in wires in a circuit

I have a hard time really understanding the electric field in a complete curcuit. How is the electric field maintained throughout the wiring / the conductors from component to component? The charges ...
1
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3answers
166 views

How does voltage divided by EMF show efficiency?

I get that electromotoric force (emf) is energy per coulomb supplied and that voltage is energy per coulomb used but I don't get what it means when we say that the voltage divided by the emf gives the ...
1
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1answer
81 views

What is the current in a circuit with two voltage sources in series? [closed]

What happens? We have 2 voltage sources and 2 currents. When I2 and I3 come together (they have opposite sides), what happens? I tried writing down the voltage relations but I'm stuck because I don't ...
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0answers
32 views

Cells in parallel

Two cells of EMF 1.5V and 2.0V having internal resistances 0.2ohm and 0.3 ohm respectively are connected in parallel. Calculate the internal resistance of the equivalent cell.
0
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1answer
418 views

Voltage across an inductor contradicts Lenz's law?

Imagine a simple circuit consisting of an alternating current source connected to an inductor. Assume they are connected in the following fashion: AC source - terminal A - Inductor - terminal B - AC ...
1
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2answers
522 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 ...
0
votes
2answers
1k views

Can a battery charger be too powerful for a rechargeable battery?

I got the impression that a regular iPhone charger can charge the iPhone and the iPhone won't become too hot while charging, and the charging time is standard, but if using the 10W iPad charger to ...
1
vote
3answers
688 views

Theoretical uncertainty of a circuit's total resistance when made entirely of resistors

My question in short(ish) is: Will the fractional uncertainty of a circuit made entirely of resistors with equal fractional uncertainties be the same as the fractional uncertainty of those resistors. ...
0
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1answer
55 views

Resistance Distance in large electrical networks

I am not tremendously familiar with electrical circuits (I have some memories, but too long ago) and now I have come accross a problem where I need to compute the resistance distance in a graph. So, ...
1
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1answer
120 views

Flux linkage of 2 coils in series

I have a question from magnetic circuits. I am an engineering student, therefore I will neglect some minor errors. There is a simple magnetic circuit with 2 coils ($C_1$ & $C_2$), with $N_1$ &...
0
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2answers
30 views

Why is it that for a source of emf, current flows from lower to higher potential?

I'm quite confused about this actually! In fact, I had always thought current flows from a region of higher potential to a lower one. Does it have anything to do with the fact that it's a source of ...
0
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3answers
21 views

Difference in directions of charge and current.?

I just dont understand that why does charge flow in a different direction as that if current when current is the rate of flow of charge.
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1answer
38 views

How does voltage produce current?

I am studying electric current and i dont understand how does voltage(potential difference )produce current? PS : I am a 10th grade student so please avoid complicated terminologies.
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0answers
17 views

Find voltage at a point on infinite ladder of resistances [duplicate]

Find voltage at point C. What I have tried. Find the effective ladder of resistances. Which comes out to be R(sqrt.3 - 1) Then find the current. 48/Reff Then split the current and find current ...
2
votes
1answer
146 views

How do the different types of energy apply to voltage in a circuit

I was just wondering what happens in a circuit in terms of different types of energy transformations. If you apply a voltage to a circuit then electrons start moving (very slowly). Since the electrons ...
0
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1answer
164 views

Internal Resistor in a Diode

When we talk about the resistance of a diode (of the P and N region), is this resistance like the one inside an Electro-Motive Force or it acts like a normal resistor (external electric field exist)? ...
-1
votes
1answer
25 views

Current flow in absence of a potential difference [closed]

What if at two different points in a wire connected to a system of capacitors and resistors, the electric potential is equal. Will the current flow? There is also a battery connected.
0
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1answer
129 views

How do these voltage vs. current graphs demonstrate how the resistance of each conductor changes during the experiment?

The method for the experiment was as follows: Connect the circuit shown above using the globe as a conductor and then replacing the globe with a 10Ω resistor. In each case record the voltmeter and ...
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3answers
43 views

Ohm's law and an ideal voltmeter

In an ideal voltmeter there is infinite resistance so because of which no current is flowing through it and the voltage reading is not affected. The ohm's law stated that V = I * R In an ideal ...
2
votes
2answers
60 views

Are these capacitors parallel or in series?

I am a bit confused. The authors say these conductors are parallel when the switch is on. But to me it looks like they are in series since the handle is insulating. How can you explain that they are ...
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0answers
23 views

PARALLEL COMBINATION OF SUPERCONDUCTORS AND RESISTORS [duplicate]

........................please reply to the question above in the picture. I have tried a lot and have thought about it for a long time. Please help me and answer in simple words. AND I REQUEST NOT ...
1
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4answers
721 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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0answers
35 views

Determine potential function given initial conditions?

Assuming a radially symmetric circular disk (let's say r=1). Given two simple initial conditions: Potential at the centre is 4 V Potential at the edges is 0 V How would I determine the potential ...
3
votes
1answer
124 views

What does a voltmeter actually measure?

For time varying fields (even quasistatic ones) the electric field is given by $${\bf E} = - \nabla \Phi - \frac{\partial {\bf A}}{\partial t}$$ So what does a voltmeter measure? Does it measure a ...
0
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3answers
38 views

Finding equivalent capacitance between A and B, [closed]

Following is the question, asked is to find equivalent capacitance between A and B. I've tried couple of times and getting 7/3 micro farad as the answer while the correct answer is 8/3 micro farads. ...
1
vote
1answer
51 views

Bulbs in parallel/series (very basic) [closed]

I need some help understanding very basic circuit concepts, specifically for the question in the image below. So from what I know is that in a series setup: voltage is divided over the components, ...
4
votes
4answers
66 views

Current in inductor just after switch is closed

I have read that the current in an inductor resistor circuit just after closing the switch is zero. This is derived by finding the differential equation in terms of current by using KVL. Is this true ...
0
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0answers
12 views

Charges on outer faces of parallel plate capcitor

Can there be charges on outer charges of a parallel plate capacitor if both the plates are initially charged by different amount and then connected with a battery.
1
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0answers
27 views

Question about notation in a simple circuit [closed]

I was given this circuit in an Electricity & Magnetism course. On the far left, is that a current source providing 2A? It seems to be but I'm not 100% sure.
0
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1answer
25 views

Difference between energy loss at high voltage and high current

When reading about power transmission one very common statement is that power is transmitted at high voltage to minimize loss in the form of heat. What confuses me is the governing equation. Aren't $...
0
votes
1answer
153 views

Why is current shared in a parallel circuit but not a series circuit?

Electricity test coming up. It's not clear to me why current is shared in a parallel circuit but not a series circuit.
1
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1answer
34 views

Is a real voltaic cell always schematically equivalent to an ideal battery and a resistor?

In the diagram I have attached, the top circuit is the schematic equivalent I am trying to use to model the middle circuit which uses real voltaic cells (that have internal resistance). I am not sure ...
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votes
1answer
25 views

Mechanism by which a capacitor is charged, using surface charges

I want to gain a deeper understanding as to how a capacitor actually gets charged. Consider a situation in which an uncharged parallel plate capacitor is connected to a battery using two wires. I ...
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2answers
338 views

Why is the voltage output equal to the voltage drop?

I have a very basic question about measurement of voltage output on some simple circuits. Considering the circuits of the figure: Supposing one wants to measure the voltage output $V_2$, on the ...
0
votes
1answer
64 views

Can we “use” a capacitor while simultaneously charging it?

I know that capacitors can be charged to work like a battery . But I wanted to know whether we can charge a capacitor while it is in use ( given that the current supplied to it is more than what it ...
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votes
2answers
62 views

What is the reasoning behind calculating the resistance between two points on a square resistor circuit? [closed]

Here, the question asks me to work out the resistance between X and Y. The answer is 1.2 ohms. In a normal circuit, the resistance between two points is simply whatever resistor value(s) is between ...
0
votes
2answers
20 views

Help with electrical current and resistances [closed]

I am working on a physics equation on electrical circuits. I understand it in one direction but I am having issues looking at it backwards. I am given the following: R1 = R2 = R3 = 1.5 Ω Calculate ...
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votes
2answers
65 views

Electrocuted at Parking Pay Station After Snorkeling [closed]

This is my first time posting here so bear with me. Also, the circumstances are strange so I am posting quite a bit of detail because I don't know what is relevant and what is not. The short story is ...
4
votes
5answers
169 views

Why aren't resistors equivalent to breaks when $R\to\infty$?

Find the voltage across each resistor as $R\to\infty$ Kirchoff's voltage law gives $$10\ \mathrm{V} - V_R-V_R = 0 \implies V_R = 5\ \mathrm{V}$$ However, don't we get two holes in the ...
0
votes
1answer
27 views

making sense of measures in electronics

I am in secondary school in the UK, and at this point in physics the information we are given is very vague at a fundamental level. My main concern is with electricity and circuits, and the measures ...
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votes
2answers
27 views

AC circuit having a capacitor

Consider a parallel plate capacitor connected to an AC. The current in the circuit leads the emf by $\pi /2$. My question is, what does it mean that the current lead the emf by $\pi/2$? Does it ...
0
votes
1answer
47 views

Internal resistance of a cell

I'm a pre-university student, during the lesson of internal resistance r, there's actually resistance in battery or a cell, and if we were to connect it up in a simple set up as below: The situation ...
1
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1answer
34 views

Ohm's law deviation

In terms of superconductivities and diodes (I do not know anything else except these), Ohm's law deviate from a linear relation. I search many titles or tags for this but I did not understand properly ...
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votes
1answer
53 views

How do I simplify this complex resistor circuit? [closed]

I have this circuit diagram and I need to find the current through the circuit.But I have no idea how to simplify this circuit. I have tried applying Kirchoff's Current Law but could not do it. ...
1
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1answer
37 views

Resistance from $I$-$V$ graph

I thought that the answer was obviously A as the gradient remains constant...however, the answer is B...who so?
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3answers
49 views

EMF or terminal voltage?

I have a doubt that is: What does this statement mean: "a 6 V battery". Does this mean that the EMF of the battery is 6 V or the terminal voltage of the battery is 6 V? If the battery has internal ...
0
votes
2answers
43 views

Contradiction about cross-sectional area being inversely proportional to resistance

Let us consider a fixed voltage. $ I = nAve $ is the relation between current, number of free electrons in unit volume $(n)$, cross-sectional area $A$ and electron drift velocity $v$. ($e$ is the ...
0
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2answers
54 views

Why don't capacitor charging graphs look like other exponential growth graphs?

Sorry if this question is stupid, but I can't find any answers for this online. Physics websites show that capacitors charge and discharge exponentially. The discharging graphs of charge against time ...
0
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2answers
4k 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 $E=\frac{...