1. Electricity

2. Types of electricity Static electricity Build up of electrical charge
Uncontrolled electrons
Discharge is sudden, momentary
Lightning

3. Types of electricity Current electricity Controlled
Constantly moving electrons
Follows a conductor
Has electrical “pressure” or voltage

4. Voltage, current, and resistors

5. Electric current and voltage difference
Net movement of electric charges in a single direction.
Measured in amperes.
flow
Voltage difference
Measured in volts.
Voltage is the measure of energy to move electrons, “push”.
pressure

6. Electric Circuits Must have a closed path for current to flow.
A closed complete circuit allows electrical current to flow.
2 types of circuits series and parallel.

8. Series circuit
A series circuit has more than one resistor and gets its name from only having one path for the charges to move along.
Charges must move in "series" first going to one resistor then the next.
If one of the items in the circuit is broken then no charge will move through the circuit because there is only one path.
There is no alternative route.

9. Series circuit
Old style electric holiday lights were often wired in series.
If one bulb burned out, the whole string of lights went off.

10. Parallel circuits
A parallel circuit has more than one resistor and gets its name from having multiple (parallel) paths to move along .
Charges can move through any of several paths.
If one of the items in the circuit is broken then no charge will move through that path, but other paths will continue to have charges flow through them.

11. Parallel circuits
Parallel circuits are found in most household electrical wiring.
This is done so that lights don't stop working just because you turned your TV off.

12. Circuit Electrical current Resistance Uninterrupted conductive loop
Rate of flow of electrons
Measured in amperes
Resistance
Opposition to electric current flow
Measured in ohms

13. Circuits

14. Parallel Circuit Each bulb on separate branch
Each bulb independent of others
City streets not circular track
Adding more bulbs
Decreases resistance on circuit
Increases current flow

15. Series Circuit
Each bulb part of same path
All on or all off
Circular track not city streets
Adding more bulbs
Increases resistance on circuit
Decreases current flow

16. Short circuit
Low resistance connection
Current flows through lower resistance
Rest of circuit bypassed

17. Circuits in your home

18. Circuits in your home
Turning on more devices- Increases active branches on circuit Decreases resistance Increases current flow

19. Circuits in your home Circuit overload
More current than conductor can handle
Potential for electrical fire
Excessive friction
Between electrons and conductor

20. Circuit Breakers Safety feature Linked in series to house circuits
Breaks circuit when excessive current flows

21. Tesla versus Edison
Edison’s least favorite of Tesla’s “impractical” ideas was the concept of using alternating current (AC) technology to bring electricity to the people.
Edison insisted that his own direct current (DC) system was superior, in that it maintained a lower voltage from power station to consumer, and was, therefore, safer.
But AC technology, which allows the flow of energy to periodically change direction, is more practical for transmitting massive quantities of energy, as is required by a large city, or hub of industry, say.

22. Tesla vs. Edison In the end, AC won out. Mostly.
Westinghouse fulfilled Tesla’s dream of building a power plant at Niagara Falls to power New York City, and built upon its principles the same system of local power grids we use today.
Edison’s original point about the practicality of DC is well-taken, however: The average person can’t have alternating currents flooding massive amounts of energy into their household appliances, so most plug-in devices must internally convert AC back to DC (that’s what’s going on inside the brick of your laptop cord).