1. Alternating Current Direct Current

2. History
In 1887 direct current (DC) was king. But DC had a great limitation (Edison)
George Westinghouse (Tesla) introduced his system based on high-voltage alternating current (AC)
A "battle of the currents" ensued.

3. Inside the wire
When you receive a shock from static electricity, tiny particles called electrons actually move between your body and some other object. 
The copper atom has one lone electron in its outer shell, which can easily be pulled away form the atom

4. Because there's only one electron in the copper atom's outer shell, it is easily pulled away. 

In a copper wire, electrons move from atom to atom in a wire, producing an electric current. 



5. Current vs. Voltage
You've no doubt heard the terms current and voltage. 

Current describes how many electrons are passing through a wire or some other object at any given moment. High current means lots of electrons are in motion. 

Voltage describes how much energy the electrons carry. High voltage means lots of energy. 

6. Alternating Current Electrons flow back and forth 60 times per second
Electrons travel in bidirectional path in circuit
Power generated from power plant
Travels over long distance to your home or business
VOLTAGE amounts 120v 208v 240v 480v
Advantages?
Disadvantages?

7. Direct Current Batteries are the most common source of DC
Maintains a constant value
Electrons travel in a Unidirectional path, point to point
Batteries are the most common source of DC
Primary Cells are intended for 1 use
Secondary Cells can be recharges for multiple use

8. Battery Construction
In its simplest form a battery consists of two different metal (copper&zinc) plates called electrodes which are dipped into an acid solution called electrolytes
The cell then produces current through the path of the two metals

9. Components of Electrical System
Voltage source = generator/batteries
Conductor = wires
Control Element = switch
Load = light bulb, motors, appliances

10. ELECTRICAL SYMBOLS
Load
Battery
AC power
Wire
Switch
Lamp