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Electronics | Foreword | Basic Electronics | Complex Electronics | Electricity | Machines | History of Electronics | Appendix | edit

Two atoms are walking down the street. The first atom says to the second atom "I think I lost an electron!" The second says "Are you sure?" To which the first states "I'm positive!"


This is a rough draft

Electronics is the study and use of devices that control the flow of electrons (or other charged particles). These devices can be used to process information or perform tasks using electromagnetic power.

Atoms, the smallest particles of matter (which cannot be divided and still blah blah), are made of protons, electrons, and neutrons.

Electrons have a negative charge, and protons have a positive charge. Neutrons have no charge. The notation that a charge is positive or negative is arbitrary.

Particles that have the same charge (such as two electrons) have a tendency to push each other away; to repel. Particles with opposite charge (such as a proton and an electron) tend to move closer together, or attract. This effect extends from every particle to infinity, although it decreases with distance. It is called the particle's electric field.

Protons and neutrons combine to form the atom's nucleus, with electrons circling them at a relatively great distance (held near the protons by the fact that they are oppositely charged).

All atoms have electrons surrounding them, which tend to exist in several layers. (The modern model of the atom, which involves quantum mechanics, is more complicated, but both models are equally valid for electronics, so we will use the vastly simpler classical model for our introduction to electronics.) The outermost electrons are free to move from atom to atom. The inner shells of electrons are held tightly to just one atom. The electrons that are free to move are called valence electrons.

Electronic devices are based on the following principles:

  1. Atoms in certain types of materials (called conductors) have many electrons which are free to move from atom to atom.
  2. Atoms in other types of materials (called insulators) do not have many free electrons, and so the electrons tend to stay attached to the same atom.
  3. Electrons are repelled from other electrons.

The most commonly used conductors are metals. Metals have electrons that are very free to move from atom to atom, and do so constantly. This is sometimes thought of as many atomic nuclei surrounded by a "sea of electrons".