Article B1: How To Read Schematics


graphic schematic In the first half of the twentieth century, one could pick any number of magazines, like Mechanics Illustrated, describing crystal sets and other electrical devices. It was popular and practical to present a crystal set using a line drawing, such at that shown to the right, which is a portion of a crystal set designed by Mike Peebles and presented in the March 2005 issue of the Society Newsletter. These wonderful drawings not only presented an overall picture of the set but clearly displayed wire routing and other physical features.

As time marched on, designers found it quicker and easier to document the electrical aspects of sets using what we call today a schematic presentation. Schematics are two-dimensional, not pictorial. Nearly all articles or documents of electronics found today use this format. Pictures are not included generally, leaving wire routing and mechanic layout a potential mystery. Too bad! Quality manuals and kits should include enough pictures to tell the story left untold without the old-time illustrated drawings.

 

schematicSince schematics dominate now, let's see how to read them. We'll use the schematic of a basic crystal set, shown at right, as our example.

In order to represent a circuit on paper (in two-dimensions), symbols were developed for each type of component used.

Congratulations! You've just read your first schematic.