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

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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 ...
-4
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1answer
35 views

Total Energy Stored in Seven Capacitors [on hold]

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 ...
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1answer
42 views

Difference of potential between points [on hold]

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, ...
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0answers
17 views

Resistance in Potentiometer [on hold]

A potentiometer is shown in the figure. a) How will the balancing length be affected if resistance (R) is increased or decreased ? b) Will the balancing length be affected if resistance (S) is ...
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1answer
25 views

How I can solve this ? (kirchhoff's law) Plz discuss it to me [on hold]

the remaining of question is ( careful choice of suitable loop can make it easier ? i choose outer loop and answer it like that: 10 Volt = ( I X 10 ohm ) + ( I X 10 ohm) but it give wrong answer ...
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0answers
41 views

Capacitor question [on hold]

Assume a 1200F ultracapacitor is initially charged to 12V by a battery and is then disconnected from the battery. If charge is then drawn off the plates of this capacitor at a rate of 1.0mC/s, how ...
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2answers
40 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 ...
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2answers
36 views

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

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 ...
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0answers
22 views

Confusions about current, voltage and capacitors [on hold]

If it's okay I have a few quastions. First of all, what is current. I've had people tell me it's negativ charges moving but also that it's negativ and positiv charges moving in different directions. ...
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0answers
28 views

Finding the component values of a series RLC circuit using an oscilliscope and signal generator [closed]

What methods could I use to find the individual values of the components - resistor, inductor and capacitor - of a series RLC circuit using an oscilloscope, signal generator and 10 ohm resistor. Where ...
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0answers
85 views

Does This Video Really Prove that Energy Conservation Can Be Violated? [closed]

I've discussed the following video elsewhere: http://youtu.be/YBMUzoUJ7ww and am more and more coming to the conclusion that the video shows for the first time scientifically sound proof that ...
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1answer
21 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 $N_1$ ...
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2answers
48 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 ...
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0answers
17 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 ...
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0answers
13 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 ...
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0answers
14 views

Design a Resistive Circuit [closed]

Design a resistive circuit with a total resistance of 31 (+-1)ohm using 8 resistors of values 5, 6, 7, 8, 9, 10, 11 and 12 ohms
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1answer
23 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 ...
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0answers
16 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 ...
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1answer
49 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 ...
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0answers
22 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
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2answers
124 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 ...
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1answer
23 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 ...
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1answer
33 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 ...
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1answer
23 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 ...
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3answers
22 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?
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15 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, ...
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1answer
28 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)? ...
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2answers
82 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 ...
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1answer
35 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 ...
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1answer
41 views

Calculate the resistance in serial and parallel circuits

I have a serial and a parallel circuit. In both of the circuits I am using two resistors.These two resistors have the same resistance $a$. In both the circuits I have tried reading the amount of ...
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2answers
32 views

Why can't I get a output lower than 0V in this circuit?

In the image above green is my input (node left side capacitor) and blue is my output (node right side of the capacitor). I would expect that the blue sinusoidal looking signal would follow the ...
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1answer
27 views

What does an induced emf do to a loop of varying current?

I know that the magnetic flux through a loop in space is proportional to the current such that $\Phi=LI$. Therefore a change in magnetic flux will produce an emf, so $\mathscr{E}=-L\dfrac{dI}{dt}$. ...
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1answer
33 views

Help me understand static electricity

This is what I understand about electricity: (The following information is paraphrased from the book CODE by Charles Petzold.) Atoms are made up of protons, electrons and neutrons. Protons and ...
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20 views

How does current flow in the circuit during negative cycle of input?

So,as far as I know the input signal just controls the current from +Vcc as per this analogy But in the first picture during the negative half cycle of the input waveform the output wave form is ...
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1answer
74 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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0answers
18 views

Equivalency of Q Factor Definitions

The Q factor is defined (seemingly) as $$Q=2\pi\frac{\mathrm{energy \, \, stored}}{\mathrm{energy \, \,dissipated \, \, per \, \, cycle}}$$ however on Wikipedia is says that the Q factor can be ...
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0answers
86 views

Difference between rheostat and potentiometer & How connections are made to a simple rheostat?

I am confused about connecting wires to a rheostat. Can you please name and explain the parts of rheostat? Also how do we know which end of rheostat is to be used in circuits? In the last picture ...
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1answer
34 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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0answers
27 views

Electron flow through insulators connected to conductors

I imagine a simple circuit consisting of a power supply and conductor connected to an insulator (heavy resistor in series with wires). In a closed circuit, I understand that the battery's E field ...
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2answers
52 views

Optimal method for solving circuit

This problem seems quite simple, and I can easily find a way to solve it but the possibility of error in my method is extremely high. This is just a sub-task of a bigger task but this is the only part ...
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4answers
72 views

Current and voltage word problem [closed]

If a conductor with a current of 200mA passing through it converts 40 J of electrical energy into heat in 30 seconds, what is the potential drop across the current ? The answer is 6KV, but I don't ...
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1answer
54 views

How should I interpret the math in showing that the potential difference and the emf in an ideal battery are the same?

I was reading Griffiths' Introduction to Electrodyamics where he says that in order to have the same current through out a circuit there are two force per unit charges acting on the circuit, $f=f_s+E$ ...
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2answers
312 views

Olympiad physics 1996 problem [closed]

I don't understand the official solution of the first problem of the 1996 International Physics Olympiad. They give this circuit: Each black box is a resistor of resistance $1\Omega$. They then ...
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1answer
47 views

Why isn't this a valid derivation of the formula for capacitors in series?

I had to derive the formula for capacitors (I decided to use m capacitors in my derivation) in series, and this is what I did. The formula for a capacitor is $$Q=CV,$$ which is the same as saying ...
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1answer
66 views

How does a magnetic field produce an electromotive force?

As I keep reading through texts and online, I keep getting conflicting views when in magnetic fields and electromotive forces are involved. From what I can see, the emf is the work done per unit ...
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1answer
110 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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0answers
19 views

Is this the creation of an electrical circuit

If I place a aa battery on the negative side and a aa battery on the positive side on to a stainless steel surface and then place a quarter on the other side have I completed an electric circuit? Is ...
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1answer
23 views

Scattering Matrix of a Given Circuit - Microwave

This might be an easy question but I couldn't find it in our course book[Microwave Engineering, Pozar, 4th ed] or on internet. I have a homework and one of the questions asks me to find the S-Matrix ...
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6answers
3k 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
65 views

Capacitance and voltage drops

Let's say that Switch $S$ is closed. I have a conceptual question: If a stream of particles acquire a potential difference upon exiting the battery, why will they lose some of that potential ...