JoeGadget's
Technical Page - 1st Edition
This edition of the page is the introduction to of a series of editions devoted to understanding electricity. Electricity has 3 forms that most people are aware of : DC, AC & RF . It does many things such as run motors and see & hear things. And yet, what is it really? Is it electrons? No.
To understand electricity .....is to follow a trail of discovery. It starts at the battery. It goes from static charge to DC to AC to RF to ionization layers in the upper atmosphere. From that point the trail of discovery goes directly back to the battery to ask once again "What is electricity ?"
This explanation is a basic science explanation. It does not involve electronics. All that is known about electricity is usually in the form of analogies. DC electricity is usually thought of as water in a pipe. A resistor equates to a skinny pipe, a capacitor to a storage tank, etc.. This analogy is desperately clung to when learning AC. It works but it fails in advanced problems. When you learn RF the analogy falls apart altogether and light is used as the new analogy. It's all the same electricity. We use it, we design circuits to use it for us, we are immersed in it in the form of radio waves from all directions. We cannot see, hear, or look at it.
If you are told the answer right now you won't really understand it. Electricity is Electromotive Force ( EMF ). EMF is an imbalance of electric charge. In its dynamic ( in motion ) form it also involves magnetic energy. Magnetic energy is the kinetic form of charge. Electrical energy is the static form of charge. It still doesn't make too much sense, does it?
The next logical question to ask is "What is charge ?". It's a characteristic that protons and electrons have. It makes them attract and repel each other just like magnets. The reason that charge exists is because matter is loosely constructed. Matter can only exist in certain ways. These ways are like sizes or patterns (quantum states). The leftover pieces are energy. The matter is stable. The energy is not. They are both made of the same stuff.
These answers still don't help understand very much. It doesn't help to understand why electricity does what it does. Why can't electricity just jump from the negative terminal of a battery to the positive one ? The same battery can send radio waves for thousands of miles. They are electricity. Why can't it just jump an inch or two instead ? The voltage of radio waves goes from 0 to a limited value that is far less that the breakdown voltage of air. It does that twice per cycle.
One side of a radio wave cannot affect or interact with the other side of the same radio wave any more than two beams of light can affect each other. If two beams of water cross do they not interact as if they had repelling charges ? When two radio waves cross each other do they co ordinate their phases or something ? No. They pass each other like waves in a pond. The number of electrons going out of a transmitters negative battery terminal is exactly equal to the number going in at the positive terminal. The radio wave is somehow born inside the transmitter. It goes out the antenna and flies away. The electrons in the battery cannot leave the battery circuit. They must all return to the battery. Is this really exactly the same stuff ? Yes. Is it like water, having some sort of freezing and vaporizing point ? No.
To understand electricity follow this trail of discovery. It may seem oversimplified at first. It must be that way. The analogies that you already know have to be used 'as is' for the trail. The alternative would be to make up new words for the same purpose. That would only add to the confusion and difficulty of understanding. The exact usage of words is very important to follow the trail. Try to hear it as if it was the first time you heard it.
Don't presume things. For example: When a battery has a charge on it, don't conclude that one side has a lot of electrons and the other side is missing the same number. That is not true. Neither is it true to say that a battery has a charge in it. The net total charge is ( and always will be ) zero. It may have a charge of energy in it. That only means that it has a measurement of energy in it. It does not mean that it has a large amount of charge inside. It does not even mean electrical energy. In that context it is a charge of chemical energy. The amount of EMF charge available is a constant. For example, the terminals of a car battery have a 12 volt charge between them.. As that charge is used it is replenished immediately to the 12 volt EMF level by chemistry. When a capacitor discharges the charge drops rapidly to zero at first and then takes forever to get completely empty of electrical charge.
The amperage leaving the battery is kinetic charge. That does not necessarily mean that electrons are leaving and reentering the battery. Positively and negatively charged molecules (ions) can do exactly the same thing. That's what's going on inside a battery when it charges or discharges. It also applies to electroplating and to the chemical 'fur' on the cars battery terminal. Consider if one battery is used to 'charge' another. Electrons flow in the connecting wires, but only ions flow inside the batteries. When the electron is the charge carrier each one carries the smallest unit of charge that may flow in a wire. When ions are the charge carriers the amount varies and it is always in multiples of the electrons amount.
This 1st Edition will also serve as the Home Page. Below are the buttons to get to the following editions of Joe Gadget's Technical Page.
4th Edition - Testing of Power Supply
5th Edition - Computer Simulation of Project
6th Edition - Testing of Transmitter Project