Questions tagged [electric-circuits]

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

2,473 questions
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Electrical systems with multiple connections to earth - is earth modelled as one region of equal potential here?

In the picture we can see a realization of a TT-System, an electrical system with multiple connections to earth at different localiations. I allready know (from this question) that the coulomb-...
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Initial Current of Inductor?

I know that a capacitor can be charged up to store energy, then if we disconnect the capacitor from the source and hook it up to a light bulb, it will light up since the energy stored is used to power ...
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Resistance and temperature relationship

When the temperature changes from $\theta_1$ to $\theta_2$, having $\alpha$, and the amount of resistance ($R_1$) in the previous temperature ($\theta_1$), we can calculate $R_2$, the amount of ...
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Calculating electrical resistivity of a material

If I plan to measure the resistivity of a high resistivity material, would it not make sense to alter the geometry of the sensor to make A/l as small as possible and reduce the voltage to get a low ...
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Question about amp-hour and batteries in series

I am a little confused about this wiring batteries in series and parallel and the effect of this on total time that these batteries can last(I suppose this is called amp-hour, correct me if I'm wrong) ...
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Why does current always go to the resistance which is lower? [duplicate]

Why does current chose the easy way? Is there a proper mathematical formula about why current tends to go over a resistance which is smaller?
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Why does current remain same in a series circuit?

Current is the rate of flow of charges with time. When passing through each resistance in a series circuit, charges lose energy and "slow" down due to collisions with atoms (metal cations). When time ...
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Is high frequency alternating current capable of rotating induction motor? [closed]

I have 100khz AC power that can light up a bulb, can I use this to run small induction motor? I want the Lorentz force to push rotor coil, I know that motor would not rotate at 100000hz rate but it ...
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Why Does a Bulb’s Individual Resistance Increase When Wired in Parallel?

When I wire three bulbs in a series, the resistance of each bulb is around three ohms (using R=V/I). If I rewire the same bulbs into a parallel circuit, the resistance of each bulb is slightly over ...
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Current through the secondary of a transformer

If I know the wattage of the primary of a transformer, and the input voltage, how do I calculate the current flowing through the secondary, if a load of some resistance is placed across the secondary?
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How to calculate total power generated?

I have a circuit with a piezoelectric transducer which converts mechanical energy to electrical. The ceramic is connected to a 1 Megaohm resistor and a voltmeter which reads voltage. If I want to ...
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Are Electrons in a Circuit Subject to Newton's Third Law?

Consider a simple electrical circuit made up of a battery, an incandescent bulb, and wire. The battery and bulb are equal in mass and are on opposite sides of a circle made up by the wire. Lastly, the ...
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Different batteries in a parallel circuit

I have come across this question in my physics textbook. Two batteries are connected in parallel to a resistor (see the above image). The first battery generates $U1 = 9V$ of voltage and its internal ...
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Free Electron-Bond Electron Interactions

I am reading an introductory textbook on electronics: Practical Electronics for Inventors by Paul Scherz and Simon Monk. In a section discussing the motion of electrons in circuits, the textbook ...
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How can be Bode diagram's phase value more than 90 degree or less than -90 degree?

It doesn't have any physical meaning, i think, because phasors doesn't have more than 90 degree or less than 90 degree value ? Also negative resistance doesn't exist.
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RMS values and phasor diagrams

In RL circuits (AC source) we use vectors to calculate the total voltage, I understand that we cannot add them algebraically because they do not exist at the same time as we are using rms values for ...
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Why do phasor derivations related to LCR circuits consider $V_c = I * X_c$ even if voltage and current are out of phase?

In a capacitor, the current leads by $\pi/2$. But even then derivations of of total voltage in LCR circuits using phasor diagrams assume that $V_{inst.} = I_{inst.} * X_c$ Where $V_{inst.}$ is the ...
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What remains the same: voltage, current or resistance? [closed]

A current 1 ampere passed through a conductor which resistance is 10 ohms, if the current become 2 amperes, then will the resistance of the conductor will remain 10 ohms, and if not, then what is the ...
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Voltages phasors in AC circuit

What does it actually mean to add voltages vectorially not algebraically in RL or RC circuits (AC source)? I know that the voltage drop across the inductor is maximum when the voltage drop through the ...
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RC circuit discharge while being connected to a battery?

I am facing a conceptual problem in analyzing the following situation which was part of a physics exam; A series RC circuit with $R = 200k \Omega$ and $C = 10 \mu F$ is connected to a 5V battery and ...
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How does resistance convert voltage to current? [closed]

This is a statement that I read mainly on books about electronics. Could someone explain why after the resistance current is what makes things work and not voltage? Example from the Art of ...
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Is internal resistance of cell part of the equivalent resistance of the network of resistors?

Do we include the internal resistance of cell while calculating equivalent resistance of network? Take, for instance, the question given. Do we include the 1 ohm internal resistance while calculating ...
Image for reference: \begin{align} &r = 0.8\,\Omega\\ &\mathscr{E} = 1.5\,\mathrm V\\ &A = B = 6\,\Omega. \end{align} The current when the switch is open, the only other resistor is ...