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# What is a short circuit? watch

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1. Hello, I've search through the internet and i can't find anything on 'what is a short circuit' i've heard it before but can someone please describe and explain to me what this is?

Thanks for your time

From John Wood
2. Well a short circuit is a basically circuit where you connect the two conductors which supply the current with a conductor of relatively low resistance.

It tends to destroy the supply if there isn't a fuse in there somewhere as it causes an excess flow of current in the electrical source.

Think thats a fair defintion.

MdSalih
3. connecting a power supply accross 0 resistance

or, if "short circuiting a component", by putting 0 resistance in parallel with the component
4. So if theres too much electric current in a circuit where there isnt a resistor it causes a short circuit?
And what exactly does a resistor do,
sorry this topic is just a bit confusing

Thanks for your time

From John Wood
5. (Original post by elpaw)
connecting a power supply accross 0 resistance

or, if "short circuiting a component", by putting 0 resistance in parallel with the component
For there to be zero resistance would a superconductor need to be used at very low temps. What do u mean - put zero resistance in parallel with the component. Does this allow all the current to be obtained?
6. that's the theoretical definition

the problem arises because there is no potential difference accross the resistance (V = IR = 0), but by putting a power supply accross it, you need there to be a potential difference, so physics breaks down. (theoreticallly)

experimentally, you will always have some internal resistance, and so your power supply will most brobably burn out.

short circuiting a component effectively removes it from the circuit, again because "voltages accross parallel components are equal" and "there is no potential difference accross the 0 resistance", meaning there is no PD accross the component.
7. (Original post by elpaw)
that's the theoretical definition

the problem arises because there is no potential difference accross the resistance (V = IR = 0), but by putting a power supply accross it, you need there to be a potential difference, so physics breaks down. (theoreticallly)

experimentally, you will always have some internal resistance, and so your power supply will most brobably burn out.

short circuiting a component effectively removes it from the circuit, again because "voltages accross parallel components are equal" and "there is no potential difference accross the 0 resistance", meaning there is no PD accross the component.
ok - well explained - thanks so much
8. (Original post by elpaw)
or, if "short circuiting a component", by putting 0 resistance in parallel with the component
if you do this would the component just not recieve any current?
9. Yes. Any self respecting electron is going to take the path with lowest resistance. Therefore there's no current through the component in parallel with the low resistance and it stops working. That's why volt meters have such a high resistance (as they're connected in parallel with a component so R needs to be high).
10. emm excuse me i still want my answers!!! youve just replied to another guy with a more complicated question!!!

From John Wood

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