Electricity, What is it?

What is electricity?

The best answer is IDM (It’s Damn Magic). When you begin to consider all that is done with electricity – generators, transformers, capacitors, batteries, etc, IDM is a pretty good description. But in it’s simplest form, electricity is the passing of electrons. If you can imagine a piece of copper wire made up of atoms (or molecules), electrical current is produced when some type of force or energy causes the electrons out of their orbit and is passed to the adjoining atom. Examples of that force or energy are friction, heat, light, chemicals, pressure, and magnetism (magnetism is used to produce the AC power in our home). I know an elementary school teacher who used to explain electricity to her students by having them form a circle. She then gave them a ball and said to pass it from one student to another. That’s a great example, the circle represents a circuit, the ball, a free electron. With the circle closed, electricity can flow. Open the circle (circuit), and it will not.

Some materials will allow this passing of electrons easier than others. These materials are know as conductors. Materials that do not easily allow this passing are called insulators.

Examples of Conductors: Copper, Gold, Silver, People (not a good thing)

Examples of Insulators: Glass, Rubber, Plastic

Direct Current (DC)
Direct Current is electricity that flows in one direction. A good example is a flashlight. When the switch is turned on, the current flows from the negative post of the battery through the lamp and back to the positive post. The filament in the lamp is not a good conductor, therefore there is resistance and heat which makes it glow and gives light.

Alternating Current (AC)
This is current that not only flows but reverses direction. Meaning it flows one direction, and then the other. Standard household current alternates 60 times per second. That’s measured in Hertz, or 60 cycles hertz. Put alternating current on a chart showing the changing (alternating ) current and it will look something like the illustration below. A quick look at the chart and you see that during the reversing of flow, the voltage goes to zero and then back up to 120 volts. Why doesn’t the light flicker? The change is so fast, the filament in the lamp doesn’t have time to cool. Slow the cycles down to 30 and the lamp would be cycling from dim to bright.

A/C pic
 Now we can look more closely at the electricity coming into a typical home. That electricity is rated at 120/240 volts, meaning there are 2 – 120v circuits coming in. This is done with 3 wires, two for the hot conductors and one for the neutral. The voltage between either hot conductor and the neutral is 120 volts. The voltage between the 2 hot conductors is 240 volts.

 The power is delivered to you by your local electric company. It is transmitted over wires, usually at a very high voltage (i.e. 10,000 volts), but before it gets to your electric meter, it is transformed to 120/1240 volts. It goes through the meter and into your electric panel, where (hopefully) all the circuits are properly fused. From there, either of the 120 volt legs is used for lighting, receptacles, and other small loads. The 240 volts is used for heavy appliances, range, dryer, heat pumps, and heating.

So that’s it in a nutshell. You have to agree, “IDM”.

Next time, grounding and safety.

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