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Introduction to Basic Electronics

by Alex Cosper

Overview

Learning electronics can be difficult since it involves visualizing something that's invisible. Billions of microscopic subatomic particles called electrons are what make electronic devices work. The key to understanding electronics is studying the process from switching an electronic device on through switching it off. You will need to learn the names of electronic components and how they are involved with electrons flowing in a circular path.
Electrons

In metals like copper wire there are billions of electrons. All it takes to make them move is to excite them with an electric charge from a battery or power source. The flow of electrons is called current. Electric charge is measured in coulombs, which represent several billion electrons. One coulomb per second is an ampere, or amp.

Conductors

Materials in which electrons move freely are called conductors. These materials are ideal for conducting electricity. Examples include steel, copper, silver and aluminum. That's why most electronic devices use some type of wire. The opposite of a conductor is an insulator, such as rubber, plastic or wood. Electrons do no move so freely in insulators. The conductor resembles a train track in function while the insulator is like a tunnel through which the track runs.
Current

Electric current flows in a circular path, called a circuit. The constant flow of electrons in a circuit is what makes an electronic device work. A battery provides "direct current" while power from a wall outlet provides "alternating current." The amount of energy used to make electrons flow is measured in volts. When you turn the device on you are creating a flow of electrons. When you turn the device off, you create a blockade in the flow of electrons. This blockade is called resistance.
Circuit Board

The circuit that creates the circular path for electrons is like a maze of interconnected city streets on a small platform printed circuit board (PC board). These boards come in many sizes. They contain several components that guide the flow of electrons.
Resistance

Several factors can slow down the flow of electrons. This fact allows you to control current by applying resistance, also called impedance, measured in ohms. When you turn a device off you are applying resistance to the current, telling an electronic component to stop the flow of electrons.
Components

Electronic components found on a PC board include transistors, resistors, capacitors and diodes. Inside these components are terminals that, like train stations, can connect wires or circuits. It is at these terminals where current can be manipulated. Transistors are on/off switches as well as amplifiers that have three terminals. Resistors have two terminals. Capacitors can briefly store an electric charge. Diodes move electrons in one direction. These are the main components used in many popular electronic devices such as stereos, radios and telephones.
Schematic Diagram

An electronic schematic diagram is merely a map of the electric circuit. While the concept of a circuit can be visualized as a circular system, on paper it is usually expressed more in square shapes. As complex as a schematic may look, its purpose is to simplify the layout of the circuit with symbols that represent electronic components and paths that show how components are connected.