Electrical Power Systems Control Power CVHS

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

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)

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

AC vs. DC

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

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

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

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

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

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

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)

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

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

Assignment Chapter 8 questions Skip 20, 22,& 25