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

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3answers
127 views

How does an Inductor “store” energy?

It seems to me that an electromagnetic field is nothing more than a collection of photons, which as I've heard, extends through space infinitely. Why is it, then, that an inductor such as simple ...
0
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0answers
32 views

How does a synchronous motor know to increase current when the mechanical load is increased?

Consider a very simple singe phase synchronous motor, such as the one shown in figure 1. This motor will not be self starting, but if an AC voltage is applied and the permanent magnet is given an ...
0
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1answer
44 views

What does “Receptor” convention refers to in RC circuits?

my question is How can we choose the convention in a circuit and what does it refer to ? Especially for a Capacitor I hear the terms "passive sign convention..." "receptor convention ..." "generator ...
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2answers
40 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?
3
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2answers
162 views

Why is the voltage of a battery equal to the emf?

We know that there is an electric field inside the battery that works against the moving electrons of a circuit. But there is also the chemical force of the battery that at some point become equal. ...
0
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2answers
61 views

Why is cap voltage negative in KVL for discharge circuit?

I was just trying to derive the equation for a capacitor discharging through a resistor, and I've run into in a problem. If I set up my KVL, then I would say $iR = V_c$ (where $i$ is instantaneous ...
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0answers
21 views

How would you measure potential difference with an external variable resistor and how would this effect efficiency as resistance increases

Was just going through a past paper and bumped into this question "How do you measure p.d with an external variable resistor and how would it affect efficiency as resistance is increasing " has ...
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0answers
66 views

how does V divided by EMF shows efficiency

I get that emf = energy per coulomb supplied and that V= energy per coulomb used but i dont get what it means when is says "how"
0
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2answers
77 views

Is it correct to use $P=\large\frac{V^2}{R}$ for AC circuits?

In one of my old notebooks, I found a problem which was basically about finding out resistance of a 100W light bulb (In my country electricity voltage is 220V). Then our teacher had used the equation ...
0
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1answer
50 views

Energy consumption on resistance in AC circuit?

The electrical part of a PM machine is described as a symmetric three-phase Y-connected circuit with floating neutral point, $e=Ldi/dt+Ri+v$, where $e$, $i$ and $v$ are vectors of emf, current and ...
0
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1answer
56 views

Different voltages between same point?

In this circuit, we determine that the emf needs to be reversed and that its value is 108.75 V. My confusion is that I thought the voltage between any two points must be the same irrespective of the ...
0
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1answer
100 views

Does the electric field inside a circuit cause a potential drop with distance?

We know that when the system reaches steady-state(current does not change with time),the electric filed inside the circuit is constant. In many textbooks and lectures,professors make a graph like this ...
0
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1answer
131 views

Why do resistors always cause a voltage drop equal to the voltage of the battery

Consider a wire connected to a battery. Now,potential is analogous to the energy of the particles.And potential in a resistor drops because of the friction inside the resistor(considering there is no ...
2
votes
1answer
76 views

Why doesn't the potential drop as a $E=\nabla V$ inside a circuit when there is no resistor?

Considering that an electric field exists outside a battery and inside a circuit, shouldn't the potential drop while we move along the wire even if there is no resistor ($E=\nabla V$)? I am asking ...
1
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2answers
147 views

Why is there electric field OUTSIDE a battery?

Correct me if I'm wrong, but a battery's electric field is like an electric field of a capacitor consisting of two parallel plates. But we know that the electric field outside the two plates is zero. ...
0
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1answer
465 views

Conductance and conductivity

What is the relationship between conductance and conductivity? Is there any formular that can explain their relationship? I am so confused.
0
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1answer
37 views

Dirichlet problem on electric circuit with many entries

Let us consider an electric circuit consisting only of resistors. Let us also distinguish some set of nodes $\partial$ which we will call the boundary of this circuit. Then we define the matrix of ...
2
votes
5answers
104 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?
0
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0answers
378 views

Graph of 1/Current on Y, and R on X axis. What does the intercept represent?

1/I on the Y axis, and Resistance on X. Gradient represents 1/V. Am I right in thinking that the intercept is representative of the Emf of the supply? As I believe the equation would be 1/I=R/V+C, ...
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0answers
20 views

Back force after capacitor is discharged

You have a mechanical hand crank generator connected to a capacitor. You charge the capacitor by cranking it (you obviously have a back current as you crank it so it is difficult to crank). At a ...
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2answers
55 views

Multimeter reading between wire & air

Why does a multimeter show 10-20 V(AC) when I connect one of its cables to the hot wire of a 220 V(AC) plug while the other cable is in the air? Also why does this not happen with a 5 V battery? (It ...
0
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3answers
216 views

Why capacitor pass AC and block DC current? [duplicate]

We know that in circuit capacitor block the DC current and pass AC current. My question is how a capacitor block DC and pass AC?
0
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1answer
46 views

If a charge needs potential difference to move

Let's consider a circuit with a ideal source of emf and a resistor. Consider the segment of wire that connects emf with resistor. If we measure potential difference at any point of the wire, this will ...
0
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1answer
60 views

Finding the current and voltage in a circuit with DC sources

I know that in a circuit with DC sources a capacitor(steady state) can be replaced with an open circuit and an inductor(steady state) can be replaced with a short circuit. My understanding is that ...
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0answers
34 views

Capacitor of Pearson–Anson oscillator

I was calculating capacitance of Pearson–Anson oscillator and comparing with simple RC circuit but I get two different values. They have significant difference. I am not clear why do they have. Could ...
0
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1answer
216 views

How does the equation $1/I = r/E +R/E$ relate to $ y=mx+c$? [duplicate]

I have a graph of $1/$current against resistance, which is a straight line of positive gradient. I know that the gradient represents $1/V$ but I can't work out how the equation $1/I= r/E + R/E$ ...
0
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2answers
2k views

What does the gradient of a graph of 1/current against resistance graph represent?

I did an experiment to investigate how current varied with changing resistance and plotted my results on a graph of 1/current against resistance.The graph is a straight line showing $1/I$ to be ...
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1answer
100 views

Variation of infinite grid of ideal one-ohm resistors: what would be the equivalent resistance between 2 points in a 3D lattice?

I'm sure that many here are familiar with this famous problem that popped up on xkcd one day: On this infinite grid of ideal one-ohm resistors, what's the equivalent resistance between the two ...
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1answer
236 views

Total Energy Stored in Seven Capacitors [closed]

The capacitive network shown in the figure is assembled with initially uncharged capacitors. A potential difference, Vab = +100V, is applied across the network. The switch S in the network is kept ...
0
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1answer
57 views

Difference of potential between points [closed]

I have the following question: What is the potential difference between point A - B? Could somebody please explain me how should I count it? The voltage U=18V. I found out that V1=8V, V2=10V, ...
0
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2answers
112 views

How do capacitors discharge?

I'm having some trouble understanding how capacitors work. I can visualize how a capacitor would charge up and how current "flows" through it. But I don't really understand the concept of the ...
1
vote
2answers
130 views

Why can't I connection the anode of a battery to the cathode of an other battery and get a current flowing? [duplicate]

If I touch the anode of a battery or connect the anode the the cathode of an other battery, none (or rather: a very small current) flows between those two. If I instead connect the connect the anode ...
1
vote
1answer
55 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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0answers
49 views

Does voltage depends on the charge present in an element?

Does the voltage depend on the charge present in a battery ? I know in capacitors q=cv. Hence charge present is proportional to voltage. Is it the same in the case of batteries?
1
vote
2answers
138 views

Does the speed of electrons depend on energy?

I would like to know whether the speed of an electron depends on energy. If yes then in a circuit when electrons flow out of a resistor the energy decreases by a considerable amount, leading to the ...
0
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0answers
20 views

Flow of alternating current in an ac circuit [duplicate]

I know that it the frequency of an alternating current is 50Hz.It changes its polarity 50 times. So in a circuit does the polarity gets changed these many times. It seems that it is well applicable in ...
0
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0answers
16 views

Current flow in a polarized capcitor

What is a polarized capacitor? I have learned that in a polarized capacitor, the negative lead must be connected to the negative terminal of the battery and so the positive. But my doubt is that if ...
0
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1answer
51 views

In a circuit, if voltage is established at both terminals, then how can components use up this voltage? [duplicate]

Suppose we use a 9V battery. Then the voltage between these two terminals is 9V. In other words, it would take 9 J of energy to move +1C of charge from the (+) to the (-) terminal by the electric ...
0
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0answers
27 views

Resistance of depletion region

The ideal diode equation is : I=Io[exp(qv/kT)-1]. My question is when we want to represent this ideal diode, it will be represented by a resistance of depletion region right? but is this resistance ...
0
votes
1answer
138 views

Why is the potential difference across these two capacitors both 9V?

So above are two difference circuits, each with a 9V battery and a capacitor of the same capacitance. $C_1=C_2$ Why is the potential difference across both capacitors 9V? Shouldn't it be less than ...
0
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0answers
32 views

Potential difference on a curcuit

Above is a simple circuit. It has a voltage of 9V between the two terminals. I have drawn red lines which look like vectors, indicating how the current will flow. From the above diagram, I have a ...
12
votes
2answers
332 views

Is there a simple proof that Kirchhoff's circuit laws always provide an exactly complete set of equations?

Suppose I have a complicated electric circuit which is composed exclusively of resistors and voltage and current sources, wired up together in a complicated way. The standard way to solve the circuit ...
1
vote
1answer
84 views

Is a CRT / Electron gun in need to be in a closed loop?

I'm trying to understand electricity and there for electrons. And so far i believe i am grasping it. But there are a few parts i have a hard time understanding. For example in as i understand it, in ...
0
votes
1answer
47 views

What happens if connect 2 points with different potential?

I have a very basic question on charge distribution in electric circuits. Let's say we have 2 independent circuits. If we connect a point with higher potential in one circuit to a point with a lower ...
0
votes
1answer
38 views

Electrical network of current sources - What happens if one source is defect?

Suppose you have connected in a parallel circuit a pair of, say for the sake of concretness 5 sources of 300 mA and 0,5 V each, which are themselves connected together in series. Hence, in total one ...
0
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3answers
113 views

Resistance of capacitors

Please I would like to know how the resistance of the plates of a capacitors work? Is it the same as a resistor? If yes, is there electric field inside the plates like inside a resistor?
0
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0answers
21 views

Problem with the sign of the Thevenin resistance in a circuit

I have the following issue: when I want to find $R_{Th}$ for a circuit with dependent sources, I excite the circuit with a voltage Vo, and then proceed to find the resulting current $I_0$. Finally, ...
0
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1answer
92 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)? ...
2
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2answers
321 views

Is there a formal proof for the superposition theorem?

I was just wondering whether there is a formal prove for the superposition theorem in electric circuits? I tried searching it online but couldn't find anything sufficient. Most of the sources assume ...
1
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1answer
75 views

Diffusion current and resistance of a diode

In a diode, there is a resistance in the p and n region, and electric field is required to move the charges in forward bias conditions. My question is: when there is diffusion current is the electric ...