Presentation on theme: " Fuses and Circuit Breakers are switches that act as safety devices ◦ Addition of appliances reduces the resistance and increases the current ◦ Energy."— Presentation transcript:
Fuses and Circuit Breakers are switches that act as safety devices ◦ Addition of appliances reduces the resistance and increases the current ◦ Energy produced enough to melt wires
Fuse ◦ Short piece of metal that melts ◦ Thickness is determined by amount of current Circuit Breaker ◦ A Switch that opens and stops current flow when too much has gone through
There are 10 ohm, 20 ohm, and 60 ohm appliances connected in parallel in a house. A 15 A fuse is connected in series with the power source for the appliances. Will the fuse blow if all appliances are operated at once?
Equivalent resistance of the appliances (1/R) = (1/10Ω) + (1/20 Ω) + (1/60 Ω) = 1/6 Ω = 6 Ω Find Current of appliances I = V/R = 120 V / 6 Ω = 20 A
Short circuit starts when there is a very low resistance If there is a low resistance, what is very large? Current Will start a fire in some cases
Find any parallel resistors. And find the equivalent resistance between them Now find the equivalent resistance with the other resistors that are in series Narrow this down until you get one total resistance through a circuit and go backwards to find the current and voltage along single resistors