| Let's stop for a moment to
consider the big picture: |
An assembled circuit board provides a way to control electricity. |
| By moving electrons or charges around in certain ways, we can accomplish
many things. We can process data (like in a calculator or computer)
record information (microphones, DVDs), display things (television, clocks, scoreboards) sense things (alarms and digital cameras) create heat and light (toasters and light bulbs) or combinations of all those at once (cell phone). |
What is Electricity? |
| While it is not essential to
have a background in electronics to be a good board designer, a basic
understanding of the general principles will go a long way towards
developing good products. In this section I will try to introduce only
the things about electronics that will really help you get the job done,
but I have to start somewhere, so just bear with me until we get to the
practical part, ok?
PHYSICS is the study of the PHYSICAL world, and to the best of our knowledge everything in it can be described as combinations of around a hundred basic building blocks, called elements. The smallest unit of an element is called an ATOM, and an atom can be thought of as a nucleus of positively charged particles (called protons), surrounded by a cloud of negative charges (called electrons). The difference between elements is in the number of protons in the nucleus. Lighter elements like oxygen and hydrogen have few protons, and heavy elements like gold and lead have many protons. Protons don't do much except identify the element type (and there are also an equal number of neutrally charged particles in the nucleus that do nothing, so we won't even discuss them) but the cloud of charges around the nucleus is what electronics is all about. |
|
ELECTRONS |
| A well-balanced atom likes to have an equal number of protons and electrons. The protons are clustered together with the neutrons in the center, and the electrons are spinning around it, like the planets in orbit. Two electrons can fit into the first orbit, eight can fit into the second orbit, and eighteen in the third. The reason for pointing this out is to highlight an interesting thing about elements. Let's look at the element called Copper. Copper has 29 electrons. All those electrons except one fit into the first three energy levels 2+8+18 with one left over that gets popped into the fourth level. That one "free electron" give Copper the property of being a good CONDUCTOR. If this is so, it seems reasonable that whatever element fills up the first four orbits completely and leaves an extra one for the fifth would also be a good conductor. Yep, That element is Silver, a very good conductor. Would you like to know what element fills the first five with one extra in the sixth? Gold, the best conductor we know of in the electronics world. Conductors are materials that can trade electrons back and forth fairly easily, and the movement of electrons through a material is called CURRENT. The point of this explanation was to illustrate the fact that some elements are naturally good conductors of electricity. Other elements with different arrangements of electrons are more RESISTIVE to current flow, and some don't allow current to flow at all, and they are called INSULATORS. |
CURRENT |
Electronics is arranging CONDUCTORS, INSULATORS and RESISTORS in various ways to control the flow of electrons. |
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TO BE CONTINUED... |