Questions tagged [short-circuits]

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56
votes
6answers
23k views

If water is not a good conductor, why are we advised to avoid water near electricity (no wet hands near circuits etc.)?

How can water be a medium to conduct current while its ionisation is so negligible that, in principle, no current should flow?
18
votes
3answers
41k views

What happens when we connect a metal wire between the 2 poles of a battery?

As I remembered, at the 2 poles of a battery, positive or negative electric charges are gathered. So there'll be electric field existing inside the battery. This filed is neutralized by the chemical ...
10
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4answers
82k views

Why does connecting a battery's positive terminal to the negative terminal of another battery not create a short circuit?

This is a question regarding the physics behind the observation. I have guessed the answer to the question, but I may be wrong, so I want to wait for the responses before posting it. Some major ...
9
votes
4answers
10k views

Why does a short circuit generate fire?

When a short circuit occurs it's obvious that there is fire. How come electric energy turns out to be heat energy? What causes the conductors to get hot when short circuit is present.
8
votes
2answers
6k views

Why is the voltage drop across an ideal wire zero?

I'm having trouble conceptualizing why the voltage drop between two points of an ideal wire (i.e. no resistance) is $0~V$. Using Ohm's Law, the equation is such: $$ V = IR \\ V = I(0~\Omega) \\ V = 0$...
8
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3answers
21k views

Proof of Thevenin and Norton theorem

How can I prove Thevenin's and Norton's theorem? Thévenin's theorem can be used to convert any circuit's sources and impedances to a Thévenin equivalent.
5
votes
1answer
79 views

Where does the sound we hear from short circuits come from?

Title is self explanatory. Whenever I see or watch a short circuit happening, there is always a humming/buzzing sound going on (e.g., the sounds we hear from this short circuit compilation video). ...
4
votes
4answers
154 views

Is short circuit technically the same as overloading?

Taking the simplest circuit: battery and resistors. If I connect lots of resistors in parallel, wouldn't that increase the current to an extent that it would be technically be very similar to ...
4
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6answers
19k views

Current when resistance is 0

A short circuit has $\rm 0$ resistance. We use Ohm's Law $\rm V=IR$. If $\rm R=0$, then $\rm V=0$. Doesn't this mean $\rm I$ can theoretically be anything? Thus $\rm I$ can be like $\rm35A$ for ...
2
votes
6answers
386 views

Why does the LED turn off if the high current is going through the short?

None of the other questions related to short circuits seems to answer my question. I understand how short circuits work theoretically, that if there is a path with no resistance in a circuit then all ...
2
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2answers
1k views

is the voltage drop of a battery that is being short circuited the same as the battery's advertised voltige

So I know this is a pretty fundamental question, but I'll ask it any way. lets say you have a 12V battery, and the positive is connected to the negative directly by a wire with negligible resistance......
2
votes
1answer
478 views

What condition are to be fulfilled for a circuit to be short-circuited?

So I am curious about how short-circuiting works. If I google, I can find some general concepts like the current is too high. But what makes a current too high? So for example if I had a battery of 5 ...
2
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1answer
73 views

Resistors parallel to short circuit

I have a trouble solving this problem. (Actually, each resistor is not parallel with the bottom wire since the voltage across each of them is different with that of wire.) In the manual, the bottom ...
1
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4answers
1k views

Voltage drop along an idealized resistance-free wire in a circuit?

If you connected the positive terminal of a battery to the negative terminal to a battery with a wire with (hypothetically) no resistance, and are asked to give the voltage drop of a segment of wire ...
1
vote
1answer
322 views

Kirchoff's voltage law applied with no circuit elements

Imagine a 1.5V battery with both terminals connected securely via a paperclip. According to KVL, the sum of voltage drops in the circuit (total energy dissipated across circuit elements) must equal ...
1
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2answers
5k views

Why does all the current flow through a short circuit if its voltage drop is considered zero?

Path of least resistance vs. short circuit I know the path of least reisistance has been clarified already However, to derive the equations you need to assume that the voltage of each parallel ...
1
vote
3answers
58 views

Would we need a battery if there was no resistance?

I'm struggling to wrap my head around this idea. Imagine that we have a wire with no resistance ($R=0$). According to Ohm's law $V=IR$, the voltage drop ($V$) between any two points would be 0, and ...
1
vote
1answer
496 views

Will placing a battery in water short circuit it? (Performing electrolysis)

I've learned about electrolysis and wanted to try it out but i've popped a couple of batteries by short-circuiting them before messing around with embedded programming so I was curious as I see on ...
1
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2answers
5k views

Potential Difference of a wire?

Imagine a circuit with only a 12 Volts battery and a wire connecting the ends of the battery. Point A and point B lies on the wire. What is then the potential difference between point A and B if the ...
1
vote
1answer
60 views

Thevenin equivalent voltage and resistance of a circuit: verification needed

Here is my reasoning: We have to sources so me must use superposition: We first replace the current source by its resistance which is infinite for an ideal current source. Now we need to measure ...
1
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2answers
1k views

If I switch on a generator connected to an open circuit, are the charges oscillating along wires?

If I switch on a generator connected to an open circuit, are the charges oscillating along wires? Where has the energy gone in the open circuit?
0
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2answers
106 views

The importance and the role of a switch in an electrical circuit

There is this simple test: Three identical bulbs are connected in the circuit illustrated in the figure. When switch $S$ is closed: a] The brightness of $A$ and $B$ remains the same, while $C$ goes ...
0
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2answers
260 views

Why do loads in a circuit limit current?

I found this quote on sparkfun.com and I'm confused. "If you DO have a load in the current, the current flow through your circuit will be limited to that which your device consumes, which is usually ...
0
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2answers
40 views

What will happen if an ideal current source is connected to a isolated resistance?

I know that ideal current source is a theoretical thing. But when it comes to solve problems we have to consider these scenarios. Now suppose an ideal current source is connected with an isolated ...
0
votes
1answer
64 views

Shouldn't there be short circuit everywhere?

Live wire and neutral wire should never come in contact otherwise there will be a short circuit... but when we take a two pin plug and insert it into the socket then at that time we don't see whether ...
0
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2answers
181 views

0 Resistance in Parallel Circuits [duplicate]

If two resistors (5 Ohms & 10 Ohms) are connected in parallel, current will flow through both resistors. Then, assume a parallel circuit (5 Ohms & 0 Ohms), why does current flows to the path ...
0
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2answers
151 views

Why do resistors heat up less than short circuited wires if resistors have higher resistance and therefore turn more voltage into heat?

If you short circuit a wire, it will heat up and possibly melt or catch fire. If you add a resistor neither the resistor nor the wire will light on fire (if the resistor is good enough). I know that ...
0
votes
1answer
150 views

Science of Short Circuits

Okay from an engineering perspective it is obvious that short circuits happen because of electrons taking the path of least resistance, thus bypassing the resistor. Just like how a short circuit in a ...
0
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2answers
519 views

Voltage across voltage source in a short circuit

When we short-circuit a voltage source, the current will be very high. The voltage across the wire is 0V. If we apply KVL, also the voltage across the voltage source is 0V. How can it be 0V if we have ...
0
votes
2answers
223 views

How does current flow in a short circuit? [duplicate]

In a short circuit, the potential difference across the terminals of a battery (consider a single cell with internal resistance)is 0 according to the equation $$V=E-Ir,$$ where $r$ is internal ...
0
votes
2answers
283 views

Effective resistance of a weird looking electric circuit [closed]

A electric circuit (in the picture) is given where all the resistance are of 1 ohm. I have to find its equivalent resistance. (9,10, 11th points are conncections) My attempt: I think electron flow ...
0
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1answer
1k views

Short circuit in superposition

I'm really confused about the concept of short circuits. I don't understand, why when you short those two voltage sources, 20 and 10 ohm resistors become parallel? What happens with 4, 12, 15 ohm ...
0
votes
1answer
759 views

Applying Kirchoff voltage law to a short circuit

If you consider an ideal wire with no resistance that shorts an ideal battery, the only voltage drop that exists is the emf of the battery, with nothing to balance it. Obviously in the real world ...
0
votes
3answers
240 views

What is the voltage at every pair of points along a ideal wire that is connecting the two terminals of a battery?

If you stick a wire across a battery, obviously it is going to discharge the battery. This will be due to a voltage difference between the two terminals. However, the equation $V = IR$ tells you how ...
0
votes
1answer
284 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 ...
0
votes
1answer
22 views

On ground wave propagation

My textbook says, (ground wave propagation) "Horizontal component of electric field in contact with the earth is short circuited" I am not understanding, what do you mean by short circuited electric ...
0
votes
1answer
48 views

Breadboard LED circuit

Please, just a quick question, am I right that the reason why LED is not lighting is: LED is connected parallel to the wire The wire has much lower resistance, so nearly all current is flowing ...
0
votes
1answer
49 views

Does a battery 'excites' current to flow in a superconductor? [duplicate]

If yes, how is it possible since a closed circuit with no resistance means 0 voltage, how does the electrons flow initially if there's no potential difference? Any simple explanation or analogy would ...
0
votes
1answer
110 views

How come no current flows through the wire of no resistance in this short circuit? [closed]

I am currently solving for the equivalent Norton current through this circuit. To solve for it, I turned my schematic into an open circuit (not pictured) and I need to calculate the current through ...
0
votes
1answer
62 views

If we put a voltage on a big square piece of aluminum sheet how will the distribution of the current look like?

Picture an enormous square piece of aluminum sheet, say of $100\times100(m^2)$, on which' two opposite corners we put a potential difference. The ensuing current is low enough to do no damage to the ...
0
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2answers
411 views

LR circuits - time constant meaning

If you have a huge time constant in LR circuits, does this mean it takes a long time to discharge and lose all current in circuit? Similarly, if you have a tiny time constant in LR circuits, does ...
0
votes
1answer
228 views

Why is Kirchoff's Voltage Rule not satisfied when the circuit is shorted?

For example if I have a simple circuit with a battery and a resistor, and then the resistor is shorted, Kirchoff's Rule is no longer satisfied. Since the current through the resistor is 0, the voltage ...
0
votes
3answers
1k views

Short circuit due to loose terminations

I have been reading into wiring and circuits and found someone post that they had a circuit breaker tripping because of a loose wire in the circuit. They claimed the hot screw/lug combination ...
0
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3answers
273 views

This question was on my physics test (about basic DC circuits) [closed]

So in the following question: Because the wire has a resistance of near 0, is there no current going through the resistor with the arrow pointing at it. I understand that normally both resistors in ...
0
votes
2answers
951 views

What is the value of EMF during a short circuit?

During a short-circuit, 'theoretically' current becomes infinite. But what about the emf? My attempt: Since the potential difference is zero, I guess the emf should also be zero. But again since p.d. ...
0
votes
1answer
329 views

Why can't I measure my solar panels short circuit current?

I connected the multimeters COM port to the negative lead on my solar panel, the 200mA port to the positive lead on the panel. I then pointed a lamp at the solar panel the voltage was around 7V, but ...
0
votes
1answer
846 views

Dependence of resistance of fuse on length

Resistance is proportional to the length. Then why is the resistance of fuse independent of length? Should it not change with a change in length?
0
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1answer
70 views

insulated charged object making contact with an open circuit

I have a circuit in where an "object" is going to be placed instantaneously in the gap of the circuit, but the object will not touch the wire on either side of the gap. The objects has two blocks of ...
0
votes
0answers
53 views

Concept of short circuits [duplicate]

Starting from my secondary school, I have never understood the concept of short circuits. For instance, why would current prefer a path with no resistance than a path with much resistance? How does it ...
0
votes
1answer
119 views

Adding a “short circuit,” changing currents

Note that this isn't a homework problem, just a question the concept. Let's take this quick circuit I drew up just now in MS paint. There are three different currents, one for the top, middle, and ...