Electrical Basics
Basic Electricity: Electricity is the flow of electrons through a medium. Media through which electrons flow easily are called, "conductors;" Those through which the flow is difficult are called, "insulators." The metal core of an electrical wire is a conductor. The rubber or plastic that surrounds it, keeping the metal from touching other wires (or you), is an insulator.

The degree to which a conductor allows or does not allow the flow of electrons is its "resistance". It is measured in ohms (named after Georg Simon Ohm).

The pressure which causes electrons to flow throw a conductor is called "electromotive force," or voltage, and is measured in volts (for Alessandro Volta, who invented what some regard as the first electric battery).

The speed with which the electrons flow is called "current," and is measured in amperes or "amps" (for André-Marie Ampère, the father of electrodynamics).

The amount of electrical "work" that gets done is called "power," and is measured in watts (named after James Watt, whose invention of the first practical steam engine brought on the Industrial Revolution).

Ohm's Law: A description of the relationship between voltage, current, and resistance, where:
  • E stands for voltage (or "electromotive force")
  • I stands for current (from the French word, "intensite"), and
  • R stands for resistance.

Ohm's Law is expressed thusly:

E = IR

So, if we know that our voltage is 120V and our current is 20A, we can calculate the resistance:

120 = 20xR

120/20 = 6

Therefore, our resistance is 6 ohms. Since the mathematical symbol for "ohm" is the Greek letter Omega, we write this answer as:

The Power Equation: Describes the relationship between wattage, current, and voltage, where:
  • E stands for voltage (or "electromotive force")
  • I stands for current, and
  • P stands for wattage (or "power")

Because of these symbols, the Power Equation is often referred to as the "PIE" formula:

P=IE

If, as in the above example, our voltage is 120V and our current is 20A, we can use the Power Equation to calculate the wattage:

P = 20 x 120

20 x 120 = 2400

...So our power is 2400W.

If, however, our voltage is 240V and our current is 10A, the equation looks like this:

P = 10 x 240

10 x 240 = 2400

...So our power is still 2400W.

The Power Equation is also known as the "West Virginia" formula, because it can also be expressed with these symbols:

W=VA