Basic Electricity What You Need to Know

Structure of an atom Shell or energy level Proton Neutron Electron Animate the electrons revolving around the nucleus in their shell Neutron Electron

Bohr model of the aluminum atom Net charge is neutral or zero 13 P 14 N Protons = Electrons 13=13 Net charge is neutral or zero

Placement of electrons in a copper atom Complete with 2 Complete with 8 +29 Animate electrons filling each shell in sequence (see Schuler) Complete with 16 Incomplete with 1

Electricity-the flow of free electrons Valance electron Positive source Negative source Free electron Animate the free electron flow of the electrons shown in red. Bound electron

Atomic structure of conductors, insulators, and semiconductors Conductor - 1 to 3 valence electrons Insulator - full valence shell Animate the outer valence shell (shown in blue) for each in sequence Semiconductor - 4 valence electrons

Sources of Electricity Heat Light Pressure Mechanical Magnetic action

- The rate of flow of electrons CURRENT - The rate of flow of electrons Measurement Point

AWG WIRE SIZES The larger the gauge number the smaller the actual diameter of the conductor.

CONDUCTOR FORMS Solid wire Stranded wire Large stranded cable Lamp cord Solid wire Stranded wire Large stranded cable Multiconductor cable

Ohm’s Law Most Important Law of Electricity This law outlines the relationship between voltage, current and resistance in an electrical circuit. Expressed as an equation: 1. I= Current in Amperes 2. E= is the potential difference measured in Volts 3. R= is the resistance measured in Ohms

                                                                            

Circuit Protection Fuses Circuit breakers

Ground Fault Interrupter Ground fault interrupters are designed to protect from electrical shock by interrupting a household circuit when there is a difference in the currents in the "hot" and neutral wires. Such a difference indicates that an abnormal diversion of current from the "hot" wire is occurring. Such a current might be flowing in the ground wire, such as a leakage current from a motor or from capacitors. More importantly, that current diversion may be occurring because a person has come into contact with the "hot" wire and is being shocked. When a circuit is functioning normally, all the return current from an appliance flows through the neutral wire, so the presence of a difference between "hot" and neutral currents represents a malfunction which in some circumstances could produce a dangerous or even lethal shock hazard