1.3 Current Flow

I've been reviewing the Navy Basic Electricity and Electronics course from the early 70s. Previous review posts have included:

1.1 Electricity and the Electron
1.2 Electron Movement

Today's module is on "Current Flow."

Here are the bullet points to remember from the second module:

• Random drift (previous module) of electrons doesn't do any work. What we want to do work is a "directed drift" of electrons, an "electron flow," also known as "current."
• To have electron flow, we need a complete circuit, a "closed circuit," a complete path for the electrons to follow all the way from the source, through a path, and back to the source. Electricity can't flow in an "open circuit," where there is a break in the path.
• This path needs to be made out of a "conductor," that is, a type of material in which electrons flow relatively easily (a path made up of an "insulator" material won't be much help at all).
• The content of the rest of this module largely has to do with the symbols for some basic items you might find in a "circuit diagram" or a "schematic." A circuit diagram is a way of drawing an electrical system using symbols for things like batteries, light bulbs, and switches. 
• The diagram at the bottom is an example of such a diagram. I have labeled the items.
• For the battery symbol, the negative side is the shorter line. Electricity flows from the negative, around, and back to the positive terminal of the battery.

Next Week: 1.4-5 Measurement of Current and the Ammeter