by Norris Chambers
There are many books available on basic electronics and electronics for beginners, but most of them seem to be written by
the same writers who write instructions for software programs or how-to leaflets on assembly of just about anything - you read a lot, but don't understand much. Actually, no subject is so complicated that it cannot be told in simple language if the writer knows his subject thoroughly and realizes that he is not writing for engineers or literary critics.
There seems to be much confusion in trying to tell what electricity is. An easy way to think of it is to imagine a bunch of little things called "electrons" sitting in a huddle and waiting for a signal to take off. A huddle of electrons, or a group of them waiting for action, is called "voltage." The more electrons you have in a group, the higher the voltage. This assembly of little people is measured in units called "volts."
These little fellows cannot go until two things happen. They must have a proper path, or road, to follow, and they must be attracted by an opposite kind...sort of like a boy to a girl! The electron has what is called a "negative charge." There must be a positive charge at the end of a path to stir them into action. A positive charge is just the opposite of a negative charge. Remember, like charges repel each other and unlike ones attract. A positive charge is really nothing more than an absence of electrons.
The path is what we call a "conductor." That means it conducts electrons, or electricity. Most metals are conductors. Copper is more commonly used, however silver and gold are better, but are usually too expensive for common use. Aluminum is an excellent conductor, however, it is rarely used because wire made from aluminum tends to be brittle and oxidizes, or corrodes, easily. Materials that do not conduct electrons are called insulators, A good example would be glass, wood, plastic, etc.
The voltage source, or area where the electrons are stored, could be a battery. In a battery nothing happens until a conductor, or path, is connected from the negative to the positive post. When this is done, the electrons rush through the conductor from the negative pole to the positive and continue to do so as long as the two are connected. This complete route, from the negative pole to the positive pole and through the battery to the negative pole again is called a "circuit."
The movement of these characters through the conductor and source is called a "current". The current is measured in units called "amperes." The more electrons that travel, the greater is the number of amperes. The number of electrons that flow can be controlled by two factors - the number of volts, or spare electrons in your source, and the size or material of the conductor. A copper conductor will let more electrons through than one made of iron or steel. The opposition that the conductor offers to the flow of current is called "resistance." Just like more men can walk down a wider path or more water can flow through a larger pipe, so can more electrons pass through a good conductor. As more water will flow through a small pipe when you increase the pressure, so will more electrons flow through a conductor if you increase the voltage. You would do this by stacking up more electrons in your voltage source. That is, use a battery with more volts - or use two batteries.
If you think of electrons as little particles that can be stacked up to form a higher voltage, and the conductor as a path they will take at the first opportunity when there is a positive charge at the other end, then you understand the first and most important basic operation of electronics. Remember that your source is called voltage, your electron movement is called current, and your path is called a conductor. The complete cycle of electrons is called a circuit, and it must have a source and a path. Our path offers some resistance to the passage of our little electrons, so it is called a "resistor." A resistor can be in the form of a planned resistance or can be the natural resistance of a conductor or any appliance we are operating. When electrons flow through a resistance, they generate heat. A good example is a light bulb. A light bulb has a filament inside that has considerable resistance. When the electrons pass through it, the heat causes it to become white hot. Air is removed from the bulb so that there is no oxygen to allow the filament to burn up, so it just gives off heat and light, and performs a useful task. Another example is the resistance coil of a toaster or an electric stove. In this case the resistance is high enough to prevent excessive current that would burn out the element.
We won't get involved in mathematics now, but it is interesting to note that the amount of current in amperes multiplied by the voltage of the source is the amount of "watts" consumed. The measure of electrical power is called a "Watt." Also, the unit of measure for resistance to current flow is called an "ohm," pronounced to rhyme with "home." Another interesting fact is that the voltage divided by the current will give you the resistance of the circuit, and the voltage divided by the resistance will provide the amount of current. The resistance multiplied by the current will give you the applied voltage. Now you know the mathematics of simple electronics.
There are many simple experiments that you can perform with very little equipment that will help impress on you the basics of electronics. A good understanding of the basics will enable you to tackle the more difficult, or advanced phases, and can eventually prepare you for a career or enable you to pass F.C.C. tests and become a commercial or ham radio operator.
But more important - electronics can be fun. Get into it and have the time of your life!
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Lesson One