1. Electrical Power Systems
Control Power
CVHS

2. Atoms Atoms are composed of:
Protons (+)
Neutrons (Neutral)
Electrons (-)
Protons and neutrons are in the center of the atom (nucleus)
Electrons revolve around the nucleus on orbits called shells

3. Electron Theory
The outer most shell of an atom is known as the valance shell
Valence electrons are responsible for electricity
Valence electrons travel from one atom to another creating a current.
Electrons move from – to + because of law of charges (opposites attract)

4. Conductors, Insulators, & Semiconductors
Atoms with a full valence shell do not release electrons easily.
The less electrons in the valence shell of an atom, the more easily it will allow current to flow.
Conductor = 3 V-electrons or less
Semiconductor = 4 V-electrons
Insulator = 5 V-electrons or more

5. AC vs. DC

6. Open vs. Closed Circuits & Shorts
All circuits must include:
Load
Power Source
Complete Path
Open – refers to a circuit that does not have a complete path
Closed – refers to a circuit that is complete and operating
Short – refers to a circuit that has a direct path from positive to negative bypassing all loads

7. Electrical Values: E,R,I,P
Resistance (R) - A measure of the opposition to the flow of electrons (current) through a material
Current (I) - A measure of the total amount of electrons flowing in a circuit in a given unit of time
Voltage (E) - A measure of the Electromotive Force (EMF) or pressure that pushes electrons through a circuit
Power (P) - A measurement of the rate of consuming energy, transferring energy, or doing work

8. Ohm’s Law & Watt’s Law Ohm’s Law – E=IR
(Voltage = Current * Resistance)
Watt’s Law – P=IE
(Power = Current * Voltage)
These formulas are used to find unknown values in a circuit

9. Practice Use Ohm’s Law and Watt’s law to solve the following problem:
Voltage = 12VDC
Resistance = 100Ω
Current =
Power =

10. Circuits Types; S, P, S-P
Circuits are organized into different types based on the possible paths of current flow
Series circuits (only one path - to +)
Parallel circuits (multiple paths – to +)
Series-Parallel Circuits (combination of above circuits

11. Magnetism & Electromagnetism
Magnetism is one of the four forces of nature
Magnetic fields can be created by running an electric current through a conductor
This is the principle behind all generators and electric motors

12. DC Motors & Generators
If a wire is passed through a magnetic field, current is produced (generators)
If a changing current is applied to a wire inside a magnetic field, the wire will move (motors)

13. Safety Your body operates on electrical signals.
Even small amounts of electricity can disrupt these signals and be very harmful to you.
100mA is generally considered to be enough current to kill the average person

14. Electricity Safety Rules
Never work on electronics equipment with wet hands/ in wet areas
Never work on energized electronics equipment with both hands
If you were not trained how/ asked to use it in this class, don’t touch it
Always wear safety goggles when doing the following operations:
Soldering
Using any power equipment on the side workbench or cordless drills

15. Assignment
Chapter 8 questions
Skip 20, 22,& 25