Overloaded circuits

1. Overloaded circuits

2. Adding more branches • Adding more branches decreases the overall resistance regardless of the resistance or that branch. • This is because each is a separate path for electricity to flow. • Consider a 2  resistor (low) in parallel with a 120  resistor (high) • Effective resistance of the circuit… • 1.967  (just less than the smaller resistor)

3. Effects of adding branches • The power used at each resistor is the exact same as if the other branches weren’t there. • If it was a light bulb it would be just as bright as if it was the only one connected. • However more power would be pulled from the source with more branches. • If it was a battery it would drain much more quickly.

4. Overloading parallel circuits • As you pull more power at each branch in your house it is simply provided and you are charged more. • You could conceivably get too much current in a wire if you plug in too many things. • If a wire is carrying more than a safe amount of current it is overloaded.

5. Overloaded wire • The resistance in the wire would cause it to heat up and could cause a fire. • You could see a purposefully overloaded wire(s) in a toaster or a light bulb. • Imagine what that could do inside a wall of your house.

6. Fuses • Fuses protect against this • Fuses have thin wires meant to break if the circuit gets overloaded, or too much current moving through. • The broken wire stops current from flowing at all (open circuit) • A blown fuse is completely useless, and must be replaced with a new one

7. Blown Fuse • Excessive heat from too much current caused this wire • to snap. • This opened the circuit stopping current from flowing.