Questions tagged [electric-circuits]

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

Electrical circuits are describable as having current flow in a complete loop, produced by some other form of mechanical, chemical, optical, nuclear, thermal or another energy. Man-made circuits being most often discussed. Electrical circuits permit the expedient delivery of energy from one location to another and/or from one type of energy to another. Anything that can be described as using electrical charge, in an electrical conductor, as a means of energy transmission, could fall into this category.

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On this infinite grid of resistors, what's the equivalent resistance?

I searched and couldn't find it on the site, so here it is (quoted to the letter): On this infinite grid of ideal one-ohm resistors, what's the equivalent resistance between the two marked nodes? With a link to the source. I'm not really sure if…
Malabarba
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Why doesn't current pass through a resistance if there is another path without resistance?

Why doesn't current pass through a resistance if there is another path without resistance? How does it know there is resistance on that path? Some clarification: I understand that some current will flow through the resistance. A depiction of this…
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In what order would light bulbs in series light up when you close a long circuit?

For a few days, I was thinking of this question. Lets assume we have a simple circuit that is 100 meters long. And lets say that we have bulbs A, B and C connected to the circuit's 30th, 60th and 90th meter relatively (from the + side). When we…
Huzo
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Intuitively, why does putting capacitors in series decrease the equivalent capacitance?

Can someone please explain, intuitively (without any formula, I understand the formulas), why the equivalent capacitance of capacitors in series is less than the any individual capacitor's capacitance? Let's take a simple case. Say we have 2…
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Cyclist's electrical tingling under power lines

It's been happening to me for years. I finally decided to ask users who are better with "practical physics" when I was told that my experience – that I am going to describe momentarily – prove that I am a diviner, a psychic, a "sensibil" as we call…
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What *exactly* is electrical current, voltage, and resistance?

I am taking AP Physics right now (I'm a high school student) and we are learning about circuits, current, resistance, voltage, Ohm's Law, etc. I am looking for exact definitions of what current, voltage, and resistance are. My teacher, as I'm sure…
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Why do we use Root Mean Square (RMS) values when talking about AC voltage

What makes it a good idea to use RMS rather than peak values of current and voltage when we talk about or compute with AC signals.
anilkumar
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Difference between live and neutral wires

In domestic electrical circuits, there are 3 wires - live, earth and neutral. What is the difference between the live and neutral wires? As there is AC supply, it means that there are no fixed positive and negative terminals. Current rapidly…
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Does alternating current (AC) require a complete circuit?

This popular question about "whether an AC circuit with one end grounded to Earth and the other end grounded to Mars would work (ignoring resistance/inductance of the wire)" was recently asked on the Electronics SE. (Picture edited from the one in…
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Birds on a wire (again) - how is it that birds feel no current? They are just making a parallel circuit, no?

I have been thinking about this and I know that other people have answered this on here, but there's one part that still baffles me, and it has to do with parallel circuits. If I connect a battery to a resistor, and connect another in parallel to…
Jesse
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I don't understand what we really mean by voltage drop

This post is my best effort to seek assistance on a topic which is quite vague to me, so that I am struggling to formulate my questions. I hope that someone will be able to figure out what it is I'm trying to articulate. If we have a circuit with a…
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If electrons are identical and indistinguishable, how can we say current is the movement of electrons?

When we talk about current, we say electrons are "flowing" through a conductor. But if electrons are identical particles, how does it make sense to talk about them flowing? To expand on that: imagine the simplest wire, just a 1-D chain of copper…
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How can Ohm's law be correct if superconductors have 0 resistivity?

Ohm's law states that the relationship between current ( I ) voltage ( V ) and resistance ( R ) is $$I = \frac{V}{R}$$ However superconductors cause the resistance of a material to go to zero, and as I understand it, as $R \to 0$, $I \to \infty$.…
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When jumping a car battery, why is it better to connect the red/positive cable first?

When jumping a car battery the standard advice is to connect the red (positive) cable first. What's the physics explanation for this?
qazwsx
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How does energy flow in a circuit? Which is correct?

I have been very interested in this question since reading Electricity Misconceptions by K-6 There are two perspectives I have come across for how energy flows in a circuit: Electrons carry charge. As the charges move, they create an…
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