Electronics Questions: How Electricity Works

Electricity is the life blood of our society. Our survival, our comfort and entertainment are all dependent on electricity, but how does it work?

Electricity is everywhere and is integrated into our modern lives like never before. Yet, many do not understand how it works or where it comes from. Electricity comes in several forms and you can use or experience electricity in many ways. It's most basic form is lightning. Your home has electrical outlets that you can plug in appliances or electronics into. Portable equipment can use batteries. You can feel static electricity. Even the sun can provide electricity when sunlight is collected with a solar cell.

It is hard to imagine modern life without electricity. Even our most basic needs like light and heat to warm our homes are taken care of with it. A life without electricity would put our society back several hundred years. Imagine candles for light, wood stoves for heat and cooking. Communication would be turned back to the mail only.

The very basis of electricity begins with electrons. To understand electrons, one must first have a basic understanding of the atom. The atom is comprised of a nucleus and electrons. All materials' electrons do not act the same. Some materials' electrons do not move easily from one atom to another, causing the material to be less conductive or non-conductive of electricity. Other materials', like most metals, electrons do move between each other easily. These are more conductive of electricity and are labeled the same, conductors. The movement of electrons is what transfers the electricity and it is also measured by that movement.

These conductors allow the electricity to move easily, however it also needs something go get it moving. The most common example of moving electricity is to use a magnet. A generator uses magnets move electrons. A generator constantly moves a magnet next to a conductive wire to stimulate the movement of electrons.

Electricity has two basic measurements, amperage and voltage. The number of moving electrons is called the amperage or current (amps). The faster or more powerful the generator is, the more electrons it can move in that conductive wire. This creates a kind of pressure with in the system, since the flow of moving electrons is limited to the size of the conductor. This pressure is measured in voltage (volts).

A battery works basically the same way. There are two terminals, a positive side and a negative side. The source, whether it is a generator or battery, will push the electrons to the negative terminal. The rate at which it pushes is the voltage. The electrons that are pushed from the negative terminal need to complete a circuit, traveling back to the positive terminal. What equipment, electronics or appliances you attach in between is called the load. The electrons will leave the negative side of the power source, energize the equipment, and flow to the positive side of the power source.

Electrical circuits, no matter how complex, need to have these four things; The source of power or electricity, such as a generator, the load or equipment, and two wires to carry the electrons from the power source and back to the power source.

Another measure of electricity is Watts and Kilowatts. Watts = (Volts X Amps). For example, a 60 Watt light bulb uses .5 Amps. Kilowatts or kilowatt-hours is a measurement of how much electricity is used. 1 Kilowatt = 1000 Watts. For example, that 60 watt light bulb uses .06 kilowatt hours. So if your power company charges .13 cents per kilowatt hour, they will charge you .78 cents per hour of usage (.06 X 1 hr) X (.13 price). A 100 Watt light bulb would cost you $1.30 per hour.

Electricity also meets resistance. Like a rock in a river, the water meets a certain amount of resistance. In electric circuits, this is measured in Ohms. Zero Ohms equals zero resistance and the greater the resistance, the lesser the current flow, or voltage.

For formulas expressing electrical equations, voltage is (V), current or amps are (I) and resistance is (r). To demonstrate how these three units relate to each other, one uses the formula I=V/r. To simplify, if you increase voltage, you will get more electricity. If you decrease resistance you will get more electricity.

The easiest way to actually see this equation is to look at a light bulb. The thin wire is called the filament. When electrical power is applied to the bulb, the filament resists the current of electrons. You can calculate that resistance by rearranging and applying the same formula, r=V/I. A 60 Watt light bulb's resistance would be 240 Ohms.

There are also two types of electrical currents, direct current (DC) and alternating current (AC). Direct current is what a battery produces, the current flows in one direction only, moving directly from the negative terminal to the positive terminal of the battery.

Alternating current is the power produced from generators or power plants. Alternating current reverses or cycles 60 times per second (in the United States). This is called Hertz (Hz) or Cycle. The electricity available in your United States home is 120 volt, 60 Hz AC power.

The advantage of alternating current is that the power company can send millions of volts from their power plants through small wires to transformers that step it down to usable voltages in one's residence.

One of the most misunderstood terms in an electrical system is grounding. Essentially, grounding provides an alternate route for the electrical current to flow by intentionally connecting the system to the earth. Grounding wires, under normal circumstances, carry no electrical load. The only time a grounding wire will carry current is when a piece of equipment or appliance is faulty. The only time you would intentionally send current through a ground because of a lightening strike or power surge, protecting the attached equipment.

Electricity is the life blood that flows through our society. Our survival, our comfort and entertainment are all affected by electricity. There still may be many mysteries and debates surrounding the definitions and what actually flows through those wires, but one thing is for sure, life would be much different without it.

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