Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Short circuit

  1. Nov 29, 2005 #1
    what is short circuit and wat happens to different circuits when it occurs.wat operates it .
  2. jcsd
  3. Nov 30, 2005 #2
    To the best of my knowledge, a short circuit occurs when there is very little or no resistance across a circuit resulting in a very large current generated.

    Correct me if i am inaccurate.
  4. Nov 30, 2005 #3


    User Avatar
    Gold Member

    You are perfectly correct.

    Well more current will flow in the circuit than needed. This may result in a fire because a wire can only handle a cirtain amount of current. As more current flows, the wire becomes hotter and then this could lead to a fire. This is why we have fuses and circuit breakers.
    Last edited: Nov 30, 2005
  5. Dec 4, 2005 #4


    User Avatar
    Science Advisor
    Gold Member

    A short circuit generally means that current is going somewhere it is not supposed to go. Excessivelyl high current is NOT a requirement in a short circuit condition. The word "SHORT" litterally means that the current is taking the 'short way around the circuit' instead of the intended way.
  6. Dec 4, 2005 #5
    I agree thus far to more as less what has been said. The common meaning for a short circuit is when the anode and cathode of a cell or battery are connected, meaning that there is only the impedance of the wires and Internal resistance of the battery between them. This tends to result in the overloading a cicuit with current often 10^2 (or greater) times more current than normal which leads to heat build up, and then sparks and all sorts of mayhem. Oh and it can seriously screw with your equipment!
  7. Oct 27, 2010 #6
    ok its a larger current current. but how is this larger current produced?
  8. Oct 27, 2010 #7
    short circuit current depends on a few main factors, but not entirely on, the voltage present, the amount of load on the circuit, the power available.

    the Bussman Fuse company has a good PDF that runs through short circuit calculations. whether or not you understand the math fully, you can get an idea of what your dealing with with results reaching 10s of thousands and even 100Ks. enjoy

    http://www.bussmann.com/library/indcon/System available fault currents.pdf
  9. Oct 27, 2010 #8


    User Avatar

    Staff: Mentor

    You came back after 5 years to resurrect your old thread, and changed your user name slightly? Or is something else going on here?
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook