Series and Parallel Circuits Chapter 9 1 Series

Series and Parallel Circuits Chapter 9. 1

Series Circuits �“Charges with ONE path to follow” Example: Christmas Lights!

Series Circuits �If there is a break in one part of the circuit. . . NONE OF THE CIRCUIT WILL WORK!

Series Circuit �The total voltage in a series circuit is spread across the loads: �a voltage drop occurs at each load where some of the total voltage is “lost” i. e. transferred to other forms of energy Voltage here = 4 V

Series Circuit �The current in any part of the series circuit is the same. . since there is only one path for the current to travel

Series Circuits �Resistance reduces or slows the flow of electrons in a circuit. �When more loads are added to a series circuit: �the total resistance in the circuit increases �the current decreases

Parallel Circuits �A parallel circuit has multiple paths for current to follow. �If there is a break in one part of the circuit, the current in that part of the circuit would stop.

Parallel Circuits �The voltage in a parallel circuit is the same throughout.

Parallel Circuits �The current in a parallel circuit is divided among the different pathways that branch off. • A junction point is where a circuit (and the current!) divides into multiple paths or where multiple paths combine

Parallel Circuits �When loads are added to a parallel circuit, the total resistance is decreased �This occurs because more loads also means more paths and more paths creates more routes for the current to flow, which actually reduces the overall resistance �This would also cause the total current to increase.

Comparing Series and Parallel Circuits �Series Circuit in a DVD Player • Remember in a series circuit, if one component ‘breaks’, then none of it works. . . • If the player stops being able to read a DVD, is it necessary for the circuit component that works the picture and sound • No. . to function?

Comparing Series and Parallel Circuits �Parallel Circuit in a House • Remember in a parallel circuit, if one component ‘breaks’, then ONLY that part stops working. . . • If the bedroom light burns out, you would NOT want the entire circuit to stop. . . it IS necessary for the other components to still function!

Comparing Series and Parallel Circuits Flashlight – cells in series � Batteries end to end means : ↑ voltage = ↑ current More light!! � But. . . more current means the batteries don’t last as long and need to be replaced more often Lighthouse – cells in parallel � Batteries in parallel means less voltage and current is used so it: LASTS LONGER! � This means it requires less maintenance which is good if you’re an out-ofthe-way lighthouse. . .

Circuit Breakers �A circuit breaker acts as a switch so it can cut off ALL power coming into the house (main circuit breaker) or. . . �It can break the circuit so current can no longer flow through a specific (branch) circuit in your house

Circuit Breakers �How does it work? �Remember a house circuit is a parallel circuit with MANY loads �In a parallel circuit, each additional load provides a new path which decreases total resistance and increases total current MORE CURRENT IN WIRES = MORE HEAT IN WIRES TOO MANY LOADS AND = TOO MUCH CURRENT TOO MUCH HEAT

Circuit Breakers � When there is too much current (and heat!) in a circuit breaker, it causes a bimetallic strip to bend, which breaks the connection and stops the current BEFORE there is a fire. . . � Once it’s cooled, you reset the switch and the circuit