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

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In an RLC series circuit on resonance, how can the voltages over the capacitor and the inductor be larger than the source voltage?

Consider an RLC circuit in series, of the form If the source drives the circuit in AC at the resonance frequency $\omega =1/\sqrt{LC}$, the peak-to-peak voltages on the capacitor and the inductor, ...
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2answers
50 views

What is the physical interpretation of Power Spectral Density (PSD) in optical tweezer?

For the calibration of an optical tweezer, the PSD of position values are plotted. If it follows a certain behavior having two regions - free diffusion and potential limited regions, then the trap is ...
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2answers
80 views
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4answers
137 views

How could a current passing through a resistance create a voltage as predicted by Ohm's Law?

I have a question about the classic relation $V = RI.$ I know that is the voltage that creates the electrostatic force. But I do not understand how, in a circuit with just a current source and a ...
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1answer
61 views

Power Dissipated by Resistor in AC Circuit [closed]

I'm having a problem with the following review question: Given the circuit: I am asked to find the power dissipated by R1 and C. I know that for C it is 0. For R1, I know I need to use Vrms (120*...
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2answers
59 views

How is electric field instantaneously generated inside a conductor connected across two terminals of a battery? [duplicate]

I have learnt that the electric field that is responsible for current flow is generated inside a conductor as soon as the two ends of the conductor are connected or brought in contact with the two ...
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0answers
29 views

For series LCR oscillations (resonance), why does current have to be maximum?

I learned about a year back that systems will go into oscillations with high amplitudes if the frequency of the forced oscillations coincide with the natural frequency of the system leading to ...
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1answer
29 views

What the intensity in a circuit when a generator is off?

Let the following circuit I have to compute $U_{AB1}$ (i.e. $U_{AB}$ when $V_1$ on and $V_2$ is off), $U_{AB2}$ (i.e. $U_{AB}$ when $V_2$ is on and $V_1$ is off) and $U_{AB}$ (i.e. when $V_1$ and $...
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1answer
42 views

Heat creation of computer electronics

The first thing I learnt in physics was that whenever anything happens heat is created. Irrespective of the process. With that in mind, electronics clearly create heat (ohmic heating I think?). But ...
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0answers
22 views

E field inside wires during transient state

I've come across an instructive paper which explains qualitatively what happens inside wires of a simple circuit during the transient state, leading to the steady state where there is an uniform E ...
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1answer
70 views

Can iron core from solenoid be diamagnetic?

So... we were measuring RLC circuit, and while we inserted core into solenoid, the amplitude on osciloscope decreased. It would imply, that the core is diamagnetic. But it is original core from PHYWE ...
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58 views

Definition of electric current

As I am taught in school that electric current is the flow of electrons, but in some places I faced another definitions like transfer of energy between electrons. I thought that it is the transfer of ...
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2answers
166 views

Can pulsating DC current be transformed?

Since pulsating DC current is changing, why doesn't it induce a changing magnetic flux in the transformer core? Is it able to induce a transformed current in the secondary coil?
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1answer
47 views

What happens to the resistance, voltage and current when DC passes through saltwater?

I have a circuit of a battery(1.5V or 9V) connected to a multimeter, a connected to 2 metal pieces in water(distilled)(see picture, in place of the LED is a multimeter). With the addition of salt 1. ...
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3answers
117 views

What is the potential difference between $a$ and $b$ in this basic circuit, when the switch is open? [closed]

My professor says the potential difference between $a$ and $b$ is the difference between the voltages on the top left capacitor and the bottom right capacitor. My friend and I however both think it's ...
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1answer
56 views

Does the current in a resistor depend on the speed of electrons?

If the speed of electrons in resistor is slow, then will the current be slow and if the speed of electrons is fast, then will the current be fast? Does the current in a resistor depend on the speed of ...
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2answers
359 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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1answer
138 views

If current takes the path of least resistance, why do parallel circuits work? [duplicate]

Why doesn't all the current flow down the path with the weaker resistance instead of dividing and going through both resistors (in a parallel setup with 2 unequal resistors)?
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6answers
15k 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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2answers
125 views

Is resistance the gradient in a $V/I$ graph?

We have a circuit where there is a variable resistor, and we increase this resistance at a steady rate, while increasing current. Thus we have increasing voltage. The gradient is defined by $dy/dx$. ...
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2answers
110 views

Solving circuit problems

I'd like to know why in a parallel loop, the voltage, along with the current, isn't divided. e.g. in this image from a youtube video the voltage in parallel loop is the same across both resistors,...
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4answers
799 views

Measuring electric conductivity

My daughter is doing a science experiment on which metal (e.g., copper, silver, aluminum, iron) has maximum electric conductivity. We are assuming we can accomplish this by using different metal, 3 to ...
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3answers
167 views

How does an ammeter in a circuit work?

Apologies for this simple question, but I'm having trouble grasping the concept of how an ammeter works. Taking the following circuit as an example: When the switch is closed, current flows ...
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2answers
17k views

How do I calculate output voltage from a given supply voltage and resistance?

I have searched everywhere but I can't seem to find out how I can calculate the output voltage (or voltage over a component) from the resistance of a resistor (or other component) and the supply ...
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1answer
40 views

Would optical signal processing still suffer from slew rate?

In electronics, analog signal processing/computation suffers from parasitic capacitance which leads to slew rate—which is the maximum change of voltage allowed, so handling super-high frequency ...
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104 views

Applying the Symmetry of DC Circuits

While practicing for a notoriously difficult exam I have continued to come across questions like the following and despite my efforts to find resources on them, I can't seem to make sense of it. ...
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2answers
122 views

In a circuit one light-second long, does it matter where in the circuit the switch is placed? [duplicate]

I was looking at this textbook example that was posted to reddit: The accompanying comments basically thrashed it saying everything was wrong. I had a specific question about it, though, and this ...
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1answer
73 views

Why is it necessary for a circuit to be complete?

Can electrons not flow through a load if they do not have a path to flow to the positive terminal of the battery? Why is it absolutely necessary for electrons to end up at the positive terminal?
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1answer
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How uniquely determined is the impedance of an infinite-chain circuit?

A recent question asked how to find the impedance of an infinite chain of series-plus-parallel circuits. The standard trick is to split the chain after the first link, and treat the tail of the ...
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1answer
48 views

Capacitance question

A capacitors capacitance, C is equal to Q/V right? If Q was somehow cut in half, would the potential difference also be cut in half, since V is directly proportional to Q? And if so, Its C would be ...
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2answers
161 views

Determine brightness of bulbs in a sImple parallel circuit [closed]

I have a parallel/series circuit given in the following link: The question, listed here: Suppose that you were to unscrew light bulb $L3$. what would happen to the other bulbs? A. $L3$, $...
2
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1answer
82 views

Visualising current in the LCR circuit

I just went through the theory of the serial LCR circuit. There current and voltage are 90 degrees out of phase with each other. Now I was trying to imagine an animation with just dots. And I ...
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0answers
65 views

Internal resistance of a battery

It is my understanding that internal resistance of the battery is mainly due to resistance of its electrodes and electrolytes. During the charge or discharge of the battery, there's a potential drop $\...
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1answer
36 views

Simple two volt source circuit - Current [closed]

THIS CIRCUIT: A=5.6 kΩ , B=5.6 kΩ, and C=10 kΩ. How the HECK do I find the currents through each resistor? Absolutely no clue. Note: I understand Kirchhoff's Laws and Ohm's Law perfectly well - ...
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310 views

Steady-State Current

I am in the process of completing some homework and have come across a question that says: "What is the steady-state current?" It is asking in reference to a circuit that includes two capacitors in ...
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4answers
2k views

Why does current density have a direction and not current?

As I understand it the definitions are as follows: Current is a scalar $I$ with units of $\mathrm{[J/s]}$. It is defined as $I=\frac{\mathrm{d}Q}{\mathrm{d}t}$. Current density is a vector $\vec{J}$ ...
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2answers
150 views

What happens in circuits where the propagation time of the electric field is significant?

Kirchhoff's current law assumes "that whenever current flows into one end of a conductor it immediately flows out the other end". I want to understand what happens when we cannot make this ...
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5answers
15k views

Potential difference (PD) and electromotive force (EMF) in terms of electrons?

I am trying to understand potential difference and electromotive force in terms of electrons. In the above 3 circuit diagrams the red shows (what I think to be) the distribution of electrons around ...
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2answers
125 views

Where does a straight conducting wire get its capacitance?

If I take a simple piece of conducting wire (of which I can calculate the resistance from the wire dimensions and resistivity of the wire material) and connect it across the terminals of a battery of ...
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1answer
44 views

Can there be an electric current drawn through a resistor from just one terminal of a battery?

The question will appear a little more sincere from the attached diagram. Will there be any flow of charge at all once the switch S is closed? If yes, then by what mechanism? for how long? What ...
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5answers
310 views

Why does not a battery kept in empty space discharge on its own? If space between the terminals is empty, what prevents the electrons to flow?

Given here is the picture of a twisted battery kept in free space (vacuum). Will the battery discharge quickly? I mean, it should discharge faster than it would if we were to connect the terminals ...
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1answer
17 views

Phase angle of a circuit

Above is the problem at hand. I know how to calculate the angular frequency and total impedance of the circuit given the information provided. However, I'm not really sure what the question is asking, ...
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0answers
24 views

Setting up current directions in multiloop circuits with more than one battery

I'm currently working on this problem: I must find the current in each battery. I have certain doubts when estipulating the currents: How many $i$ exists in this problem? The current going in a ...
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4answers
852 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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2answers
64 views

Why does a capacitor in an AC circuit allow a lamp to glow continuously

How does the capacitor allow the lamp to glow continuously, but would not do so if the circuit was DC.
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3answers
810 views

Why do Capacitor Inductor circuits Oscillate instead of reaching equilibrium?

When the capacitor is fully charged there is a potential difference between its poles and that creates a current. This current would create a magnetic field that is changing in the Inductor (because ...
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3answers
93 views

How to detect if resistors are in parallel or series?

Some circuits are easier to see which resistors are in parallel or series. However, when faced with a more complex circuit, I can't figure out which ones are in series or parallel. I am currently ...
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0answers
53 views

Coupling of LC circuits

I am reading an old article in a physics journal in which the author explains that the frequency between two identical, but capacitively coupled oscillators becomes $\omega_\pm=\omega_0\sqrt{1\pm\...
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Can a magnetic lock be negated or overcome by a stronger electro magnet? [closed]

Magnetic locks seem to be fairly standard on modern buildings. Is it, though, possible to negate a magnetic lock my placing an oppositely-polarized, strong electromagnet across from the magnets on the ...