Electric & Magnetic Fields | Glossary | For Teachers | Brochures
Amperage - Measures electric current - the number of electrons flowing though an electric wire. Amperage can be compared to the size of the spray that comes out of a nozzle on a garden hose. A large spray compares to high amperage.
Circuit breaker - Switch or relay that breaks (opens) an electric circuit and stops the electric current. Circuit breakers are found in distribution panels.
Conductors - Material through which electricity travels easily. Electricity conducts well through metals and water.
Distribution panel - A gray box in the basement of most houses that distributes the electricity throughout the house. Electricity travels from the generating station to the distribution panel to lights, outlets and electric appliances.
Distribution line - Power lines carrying electricity from substations to pad or power pole transformers. Distribution lines are often supported by wooden power poles.
Electric circuit - The path that electricity takes when moving from an object that contains too many electrons (negatively charged) to an object with no charge or that has too few electrons (positively charged). A flashlight is a simple electric circuit, as electricity moves form the negative post (-) on the battery to the light bulb to the positive post (+).
Electrically neutral - Matter that contains no electric charge. Most matter on Earth is electrically neutral.
Ground - Object that can carry electricity and is touching the earth. Electricity always wants to find a path to ground, or a grounded object through which it can travel to get to the earth.
Ground wire - A green or bare wire in household wiring that is designed for safety. A ground wire is one of three wires in all household wiring. The ground wire's purpose is to direct any short circuits into the ground instead of through a person.
Insulators - Material through which electricity does not travel well. Glass, rubber and plastic are good insulators.
Lightning - The release of static electricity, formed from water molecules rubbing against each other when storm clouds are developing.
Milliamps - Small units measuring the flow of electricity. One thousand milliamps equals 1 amp.
Negatively charged - Matter that contains extra electrons. If a neutral or positively charged object touched the negatively charged matter, the electrons would flow out of the negatively charged matter and it would become electrically neutral.
Path to ground - Route electricity takes to get to the ground or earth. Electricity is constantly searching for the shortest route available to the ground or earth. The path to ground is the path electricity follows from the electricity source to the ground.
Positively charged - Matter that contains too few electrons. If a positively charged object touched a negatively charged object, electrons would flow out of the negatively charged object into the positively charged object and it would become electrically neutral.
Service line - Low voltage power lines that carry electricity from the power pole or pad transformers to customers. Service lines carry two 120-volt lines of electricity into houses.
Short circuit - Any break in an electric circuit that provides a shorter path to ground for the electricity. For example, if a hot wire in an electric lawn mower becomes loose and touches some metal part of the mower, the electricity will run through the lawn mower into the ground. This is a short circuit.
Substation - Facility operated by power companies that houses transformers. Transformers change electricity from one voltage to another.
Transformer - Changes electricity voltage. Electricity is transformed to a very high voltage before it is transported through transmission lines. However, homes and businesses require low voltage electricity. Transformers convert the electricity to the lower voltage. Transformers are found in substations and on power poles. Transformers are also found underground on buried power lines.
Transmission lines - High voltage power lines supported by high, steel transmission towers. Transmission lines carry high voltage electricity.
Voltage - The "pressure" of electricity in a circuit, like the water pressure in a garden hose.