HOW ELECTRICITY WORKS
Poppajohn will try to answer your questions about Electricity as best he can

To start let's get terminology out of the way so we can stay as litttle confused as possible.

The three most basic units in electricity are voltage (V), current (I uppercase "i") and resistance (r). Voltage is measured in volts, current is measured in amps and resistance is measured in ohms.

A neat analogy to help understand these terms is a system of plumbing pipes. The voltage is equivalent to the water pressure, the current is equivalent to the flow rate, and the resistance is kinda like the pipe size. There is a basic equation in electrical engineering which states how the three terms relate. It says that the current is equal to the voltage divided by the resistance. I = V/r

Let's see how this relation applies to the plumbing system. Say you have a pressurized tank of paint connected to a sprayer that you are using to paint the fence. What happens if you increase the pressure in the tank? You probably can guess that this makes more paint come out of the sprayer. The same is true of an electrical system: Increasing the voltage will make more current flow. Let's say you increase the diameter of the sprayer and all of the fittings to the tank. You probably guessed that this also causes more water to come out of the hose. This is like decreasing the resistance in an electrical system, which increases the current flow.

Electrical power is measured in watts. In an electrical system power lets call it (P) is equal to the voltage (V)multiplied by the current (I). P = VI

The water analogy still applies. Take a water hose and point it at a garden wind mill like the ones that are used to dress up peoples gardens. You can increase the speed of the wind mill in two ways. If you increase the pressure of the water coming out of the hose, it hits the wind mill with a lot more force and the wheel turns faster. If you increase the flow rate, the waterwheel turns faster because of the weight of the extra water hitting it.

In an electrical system, increasing either the current or the voltage will result in higher power. Let's say you have a system with a 6-volt light bulb hooked up to a 6-volt battery. The power output of the light bulb is 100 watts. Using the equation above, we can calculate watts out of this 6-volt bulb. You know that P = 100 W, and V = 6 V. So you can rearrange the equation to solve for I and substitute in the numbers. I = P/V = 100 W / 6 V = 16.66 amps What would happen if you use a 12-volt battery and a 12-volt light bulb to get 100 watts of power? 100 W / 12 V = 8.33 amps So this system produces the same power, but with half the current. There is an advantage that comes from using less current to make the same amount of power. The resistance in electrical wires consumes power, and the power consumed increases as the current going through the wires increases. You can see how this happens by doing a little rearranging of the two equations. What you need is an equation for power in terms of resistance and current. Let's rearrange the first equation: I = V / R can be restated as V = I R What this equation tells you is that the power consumed by the wires increases if the resistance of the wires increases (for instance, if the wires get smaller or are made of a less conductive material). But it increases dramatically if the current going through the wires increases. So using a higher voltage to reduce the current can make electrical systems more efficient. The efficiency of electric motors also improves at higher voltages. This improvement in efficiency is what is driving the automobile industry to adopt a higher voltage standard. Carmakers are moving toward a 42-volt electrical system from the current 12-volt electrical systems. The electrical demand on cars has been steadily increasing since the first cars were made. The first cars didn't even have electrical headlights; they used oil lanterns. Today cars have thousands of electrical circuits, and future cars will demand even more power. The change to 42 volts will help cars meet the greater electrical demand placed on them without having to increase the size of wires and generators to handle the greater current.

A different way of saying it is found on the website of a company called Powerstream They are an electrical design company that sells electrical conversion equipment, located in Utah and are probably easier to understand.

Okay let's start over again:

Electricity Basics

Toward the end of the 19th century, science was barreling along at an impressive pace. Automobiles and aircraft were on the verge of changing the way the world moved, and electric power was steadily making its way into more and more homes. Yet even scientists of the day still viewed electricity as something vaguely mystical. It wasn't until 1897 that scientists discovered the existence of electrons -- and this is where electricity starts.

Matter, as you probably know, is composed of atoms. Break something down to small enough pieces and you wind up with a nucleus orbited by one or more electrons, each with a negative charge. In many materials, the electrons are tightly bound to the atoms. Wood, glass, plastic, ceramic, air, cotton -- these are all examples of materials in which electrons stick with their atoms. Because the electrons don't move, these materials can't conduct electricity very well, if at all. These materials are electrical insulators. Most metals, however, have electrons that can detach from their atoms and zip around. These are called free electrons. The loose electrons make it easy for electricity to flow through these materials, so they're known as electrical conductors. They conduct electricity. The moving electrons transmit electrical energy from one point to another.

Think of electrons as pet dogs and a negative charge as a case of fleas. Homes where the dogs lived inside or within a fenced-in area would be the equivalent of an electrical insulator. Homes where the pets roamed free, however, would be electrical conductors. If you had one neighborhood of indoor, pampered pugs and one neighborhood of unfenced, free-roaming basset hounds, which group do you think could spread an outbreak of fleas the fastest?

­Dogs aside, electricity needs a conductor in order to move. There also has to be something­ to make the electricity flow from one point to another through the conductor. One way to get electricity flowing is to use a generator.

There is a definite link between the phenomena of electricity and magnetism. A generator is simply a device that moves a magnet near a wire to create a steady flow of electrons. The action that forces this movement varies greatly, ranging from hand cranks and steam engines to nuclear fission, but the principle remains the same.

­One simple way to think about a generator is to imagine it acting like a pump pushing water through a pipe. Only instead of pushing water, a generator uses a magnet to push electrons along. This is a slight oversimplification, but it paints a helpful picture of the properties at work in a generator. A water pump moves a certain number of water molecules and applies a certain amount of pressure to them. In the same way, the magnet in a generator pushes a certain number of electrons along and applies a certain amount of "pressure" to the electrons.

In an electrical circuit, the number of electrons in motion is called the amperage or current, and it's measured in amps. The "pressure" pushing the electrons along is called the voltage and is measured in volts. For instance, a generator spinning at 1,000 rotations per minute might produce 1 amp at 6 volts. The 1 amp is the number of electrons moving (1 amp physically means that 6.24 x 10¹⁸­ ­electrons move through a wire every second), and the voltage is the amount of pressure behind those electrons.

­A generator may get your electrons moving along, but you'll need an electrical circuit to do anything with it. Find out why next.