 What Is Electricity?

Watt indeed! We're no scientists or engineers, but we like to think we know a bit about what happens when we turn on the light switch in our office and switch on the computer. So, we'll do our best to explain the workings of electricity and its terminology so that even we could understand it (we hope!).

Tell Me Why

Here's a short definition of what electricity is:

Electricity is the flow of electrons through a circuit. The force or pressure of moving electrons in a circuit is measured as voltage. The flow rate of electrons is measured as amperage. The power of a system is measured as watts.

And here's a list of the various components that make up the above definition and help answer "What is electricity?":

A volt is the unit of force (electrical pressure) that causes electrons to flow through a wire. Volts are abbreviated V, or expressed by the symbol E. Electrical pressure is sometimes referred to as the electromotive force (EMF). Some common voltages used in light-duty electrical systems include 12v, 24v, 48v. Most homes use 120v and 240v systems.

An ampere or amp is the unit of electrical current flowing through a wire. Amps are abbreviated A or expressed by the symbol I (for intensity of current). Just as pipe is sized by the rate of water passing through it, a wire is sized according to the rate of electrons (amps) flowing through it. One amp of current flowing for one hour is referred to as an amp-hour (Ah). The term amp-hour is commonly used when describing battery capacity.

Watt You're Doin'

Are you still with us? We hope so and we hope we're gradually answering the question, "What is electricity?" for you. Not much more to go, so please, please us and stick around!

OK, watt's next? Ah, yes, our old favorite....

A watt is a unit of electrical power equivalent to a current of one ampere under a pressure of one volt. Watts indicate the rate at which an appliance uses electrical energy or the rate at which electrical energy is produced. Since consumers need to gauge how much electricity they use, the watt-hour, an electrical unit of energy, is an important measurement. An appliance that consumes electrical energy at a rate of one watt for one hour will have consumed a quantity of electricity equal to one watt-hour.

To calculate watt-hour, there are two things you’ll need to know:

• An appliance’s rated watts.
• The estimated duration of time the appliance will be operated.

The term watt-hours probably sounds familiar, since utility companies bill their customers for the number of kilowatt-hours consumed. Kilowatt-hours of electricity are equal to 1,000 watt-hours and are abbreviated kWh.

Types of Current

There are two types of electrical current. Alternating current (AC) is electric current in which direction of flow reverses at frequent, regular intervals. This type of current is produced by alternators. In an alternator, a magnetic field causes electrons to flow first in one direction, then in the reverse direction. Electric utility companies supply alternating current.

Direct current (DC) is electric current that flows in one direction. Direct Current is the type of current produced by PV modules and stored in batteries.

What is electricity? We've got an equation for that!

Here we'll sum up what we've just discussed in what we think is a pretty neat little equation or two for you:

Power = Watts (W) = Volts (V) x Amps (A) 1,000W = 1 Kilowatt (kW)

Energy = Watt-hours (Wh) = Watts x Hours 1,000Wh = 1 Kilowatt-hour (kWh)

Amp-hours (Ah) = Amps x Hours

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And just to round off - here's an illustration of how watt-hours are calculated:

Problem: How much electrical energy is consumed if a 100-watt light bulb is used for 10 hours?

Solution: 100 watts X 10 hours = 1,000 watt-hours (or 1 kilowatt hour).
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Phew! Made it. Well, we hope we've answered that nagging question, "What is electricity?", for you. If you've still got questions, feel free to contact us or check out some of our other pages concerning the wacky world of electricity back in our Energy Education Center!

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