1. Electricity Theory
VIR PIV and Capacitors!!!

2. Energy
PEg
When an object is at some height in a gravitational field it is said to have gravitational potential energy, PEg

3. Energy
Like gravitational fields causing masses to have potential energy, Electric Fields cause charges to have electric potential energy, PEE
PEE is a type of mechanical energy
MEtotal = KE + PEg + PEs + PEE

4. Energy
To give something PE you must do work (apply force over a distance) on the something (raising up in g-field)
For PEE to occur a FE must be applied by either
An E-Field (uniform)
A pair of charges

5. Energy Uniform E-field B A Line Color Red: E-Field
Black: Equipotential lines
Blue: charge displacement

6. Energy
Pair of Charges

7. Electric Potential
Any point in an electric field is said to have Electric Potential, V. However, only a Difference in PE is measurable (remember zero point) so we talk of electric potential difference AKA potential difference, ΔV.

8. Potential Difference

9. Potential Difference

10. Potential Difference
Back to the zero point A convenient zero point to chose in a circuit or any electric system is the “ground”

11. Battery (cells)
A battery produces electricity by transforming chemical energy into electrical energy

12. Battery
Carbon Electrode +
Zinc Electrode
Sulfuric Acid

14. Capacitor
A capacitor is a storehouse of charge and energy that can be reclaimed when needed for a specific application
A capacitor will only charge to the potential difference between the terminals of the battery

15. Capacitance
Capacitance, C: The ability of a conductor to store energy in the form of electrically separated charges
Capacitance is the ratio of charge to potential difference

16. Capacitance
Capacitance depends on size and shape

17. Capacitor
Energy stored in a capacitor

18. Electric Current
Movement of electric charge
Rate of charge movement

19. Charge Movement

20. Charge Movement

21. Circuit Analogy

22. Types of Current
AC  Alternating current  charges continuously change direction forward and back at 60 Hz
Example: outlets (approx 120 V)
DC  Direct current  charges move in one direction
Example: batteries
AC-DC Debate births the Electric Chair

25. Resistance
Resistance is the impedance of the motion of charge through a conductor
The ratio of potential difference across a conductor to the current it carries

26. Ohm’s Law

27. Resistance
Depends on: Length, cross sectional area, material, and temperature

28. Resistance and Temp

29. Resistance and Thickness

30. Resistor An electronic element that provides a specified resistance.
A current or voltage REGULATOR

31. Power (it’s Electric!)
Power: Rate at which work is done. OR Rate at which energy is transformed
Electric Power: The rate at which charge carriers convert PEE into non-mechanical energy

32. Reading and Homework Read Chapter 17 HW due on test day:pp
HW due on test day:
p ; p 601 2, 3, 5-9;
p – 4 (B); p609 1 – 5
p – 6; p , 7,9
p – 5
Extra Practice
p 626 – , 20 – 54