Resistivity is how much a substance will resist current
Resistors resist current by having the electrons flow through a less conductive substance
Different substances conduct and resist different amounts
3 of 7
Resistance
How resistance works
Resistance is made up of three things
Wire/resistor thickness(area)
Length of wire/resistor
Material
Ohms law can be rewritten as R=V/I
Naturally the idea may come that changing voltage or current changes resistance but resistance is a constant that can only be changed by the material, area, and length R=ρL/A
4 of 7
Circuits
What is a circuit?
A path that electrons can flow through
Place components in that path which use energy from electrons
Two types of circuits
Series
Electrons have only one path to flow
Parallel
Electrons have more than one path to flow
5 of 7
Series Circuit
Series
Electrons going one way
Lined up in a series
Rules for series circuits
Total voltage is equal to sum of the voltage across the components Vtot=ΣVcom.
Total amperage is constant throughout the circuit, every component receives the same amps, Atot=Acom.
Total resistance is equal to sum of resistance across the components Rtot=ΣRcom.
6 of 7
Parallel Circuit
Parallel
Electrons have multiple paths to flow
Notice how the wires for the lightbulb are parallel to each other
*in a parallel circuit the wires don't have to literally be parallel
Notice how electrons flowing from the battery can either go to the top bulb or bottom