Electricity Fundamentals

electricity

a form of energy in which electrons move from one atom to another atom.

atom

smallest particle of any element, of which all matter is composed of

the center of an atom is called the nucleus and it contains:

protons and neutrons

protons

atomic particles with a positive charge

neutrons

atomic particles with a neutral charge

electrons orbit around the nucleus and are

atomic particles with a negative charge

electrons located in the outer shell are called

valence electrons

the energy released by the movement of free electrons from one atom to another is called

electricity

a substance made up of atoms with 3 or less electrons in it’s valence shell is called a

conductor

a substance made up of atoms with 5-8 electrons in it’s valence shell is called a

insulator

The Law of Electrical Charges states:

like charges repel, and opposites attract

Electromotive force is also referred to as

volts

T or F: Electromotive force (emf or volts) is not electricity. It is the driving force that causes electrons to move from one point to the other.

True

When the electrical charge (positive versus negative) between two points is not in balance, the imbalance of electrons is called a

potential difference

the unit of measure for potential difference is the

volt

the quantity of emf (volts) is measured with an instrument called a

voltmeter

voltmeters measure the difference between

two specific points

how fast does an electrical impulse travel?

speed of light (186,000 miles/sec)

the term ampere is used to describe

the intensity of electron flow (or current)

an ammeter is used to measure what?

the amount of electrical flow

What letter is used for amperage in calculations?

I (for intensity)

What letter is used for voltage in calculations?

E (for electromotive force)

What letter is used for resistance in calculations?

R

what is resistance?

anything opposing the flow of electrons

what is resistive resistance?

resistance that remains constant.

What are examples of devices with fixed resistance?

toasters and electric heaters

what is reactive resistance?

resistance that resists a change in current or voltage.

What is an ohm?

the unit of resistance.

what does continuity describe?

a complete circuit (path) for electron movement from one point to another

what can a continuity check be used for

to prove that wires are not broken, fuses are not blown, or switched are not open in an electrical circuit.