A resistor is an electronic component used to limit (that is, resist) current flow and divide voltage and they are a very common electrical component.
Shown in Figure 2.6 are a physical resistor (left-hand side) and two schematic symbols (right-hand side). There is no practical difference between the schematic symbols pictured. They represent different documentation standards, and you will find that the author of a schematic diagram will choose and stick with one type of symbol. We'll be using the zig-zag symbol throughout this book:
Resistors come in many shapes, sizes, and colors. As a general guide, their physical shape and size relate to their physical properties and capabilities, while the color of their casing is usually insignificant, at least as far as their properties are concerned. The colored bands on a resistor, however, are very significant as they identify...