1. Electrical Theory

2. Electricity is a form of energy that can be used by electrical devices to perform work
For electricity to flow there must be a circuit
An electrical circuit contains, at minimum, a voltage source, a load, and conductors to carry the electrical current
The atomic theory explains the construction and behavior of atoms

3. The atom is the smallest part of an element that enters into a chemical change, but it does so in the form of a charged particle – these particles are called ions
There are positive and negative ions
Positive is positively charged
Negative is negatively charged
They repel each other

4. A proton is positively charged
An electron is negatively charged
Protons repel protons
Electrons repel electrons
Protons attract electrons
The outer shell of an atom is called the valence shell

5. Electrons found in the valence shell are called valence electrons
These electrons determine an atoms ability to gain or lose electrons
Valence electrons are most concerned with electricity because they are the easiest to break loose from their parent atom

6. Conductors – easily conduct the flow of electricity - usually have three or less valence electrons
Insulators – do not conduct electricity to a great degree – usually have five or more valence electrons
Transformers – step the voltage down to lower levels

7. Voltage we get at home (from the power company) is usually about 220 volts
At wall outlets the voltage is about 120 volts
The basic unit that current is measured is ampere or amp (A)
The force that causes electrons to move is called voltage or volts (V)

8. Resistance is an opposition to current
A resistor is a device that resists current flow
Resistance is measured in ohms (R)
Ohm’s law defines the relationship between current, voltage, and resistance

10. Series circuit - provides only one path for current flow and is a voltage divider – one goes out they all go out
Parallel circuit – each load is connected directly to the voltage source – the voltage is the same through all loads and current is divided between the loads – one goes out others stay on

11. Kirchhoff’s voltage law states that the algebraic sum of the voltages around any closed path is zero
The sum of the voltage drops around the circuit must equal the voltage applied to the circuit