3 Potential Difference Provided by the battery AKA voltage measured in voltsIt is a “push” for the electrons in the wire that causes them to flow.The battery DOES NOT supply the electrons, they are already in the wire.
4 Current: The rate at which electrons flow through a conductor 𝐼= 𝑞 𝑡Current: I measured in C/s (amp)The battery supplies the potential difference needed for the electrons to flow. THE BATTERY DOES NOT SUPPLY THE ELECTRONS THEMSELVES!Current only flows if there is a complete circuit!
5 Conservation of charge Total current into a junction must equal the total current out.3 AmpsMagnitude and direction of current flow?6 Amps4 AmpsInout6 amps4 amps3 ampsTotal in: 9 ampsTotal out: 4 ampsThe unknown current is 5 amps out of the junction (to the right)
6 Simple Circuit Every Circuit must have A source of potential difference (battery)A conducting material (wires)An electrical load (resistor/lightbulb)
7 Circuit SymbolsDraw a circuit with a battery, a lamp and a switch using the symbols above
8 Resistance A resistor is any electrical device that you plug in. It impedes the flow of electronsThe resistance of an object is DIRECTLY related to temperature.The hotter the wires, the more resistance they have.The resistance of a wire depends onIts lengthThe material its made of (resistivity)The cross-sectional area of the wire
9 Calculating Resistance Resistance is measured in Ohms (Ω)Calculating Resistance
10 Circuits Measurements AmmeterVoltmeterMeasures current (in Amps)Wired IN SERIES with the resistorHas a very LOW resistanceMeasures potential difference (in Volts)Wired IN PARALLEL with the resistorHas a very HIGH resistance
11 Types of CircuitsSeriesOne complete loopParallelMultiple paths
12 Ohm’s Law𝑽=𝑰𝑹Slope = ResistanceVISlope = 1/ResistanceIVResistance and current are INVERSES of each other. As one increases the other decreases!RI
13 Electrical Power When resistance is constant “ohmic” “Follows ohm’s law”“constant temperature”When Potential Difference is constantPIPI
14 Electrical Power When resistance is constant “ohmic” “Follows ohm’s law”“constant temperature”When current is constantPVPV
15 When Voltage is constant When current is constant Electrical PowerWhen Voltage is constantWhen current is constantPRPR
16 Electrical Energy (AKA work) Measured in Joules