# Homework Help: Circuit breakers and short circuits

1. Nov 30, 2007

### GT1981

1. The problem statement, all variables and given/known data
Hi,

This isn't so much an actual problem, just more of a general question. Can anyone give me a layman's explanation of what a short circuit is and how a circuit breaker deals with that? Or, can anyone refer me to any sources that can? I have taken high school physics, so anything along that level would be greatly appreciated!

THANKS SO MUCH!

_GT

2. Relevant equations

3. The attempt at a solution

2. Nov 30, 2007

### mjsd

short circuit is an unwanted pathway (usually much lower resistance than any other paths) where electrical current travels through to reach the "sink" (say ground, earth, -ve terminals). The reason that electrical current will flow through this path than through other paths because it has much lower resistance. As a result, a huge amount of current will go through this path --> dissipating huge amount of energy on the path--> making it to heat up and burnt...and fire etc.

the circuit breaker is a device that cuts of power when the current being drawn is too high, usually as a result of a short circuit (remember it has low resistance and so it "encourages" more current to flow). the breaker can be just a fuse: when the fuse gets too hot it breaks and stop the current flow BEFORE other part of the circuit starts burning. or it could be made up of a thermostat, using the fact that it will gets hot when there is a short circuit (from high current),... basically, the thermostat bends and if it is hot enough, it will bend far enough to trigger a cut of power.