Questions tagged [electric-circuits]
An electronic system, with closed loop current flow, and relative electrical potentials present across electrical components.
4,620
questions
131
votes
2
answers
102k
views
On this infinite grid of resistors, what's the equivalent resistance? [closed]
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?
...
77
votes
20
answers
28k
views
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 ...
62
votes
6
answers
9k
views
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 ...
60
votes
16
answers
15k
views
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?...
58
votes
7
answers
21k
views
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 ...
51
votes
14
answers
13k
views
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, ...
51
votes
3
answers
227k
views
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.
51
votes
8
answers
207k
views
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 ...
49
votes
6
answers
16k
views
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 ...
45
votes
11
answers
12k
views
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 ...
42
votes
15
answers
103k
views
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 ...
40
votes
9
answers
7k
views
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:...
34
votes
5
answers
40k
views
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?
33
votes
10
answers
11k
views
What happens to an inductor if the stored energy does not find a path to discharge?
Suppose an inductor is connected to a source and then the source is disconnected. The inductor will have energy stored in the form of magnetic field. But there is no way/path to ground to discharge ...
33
votes
6
answers
23k
views
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 ...