Changes

Resistance is the opposition to the flow of current; it an inherent property of most electronic components. It is one of the fundamental quantities of electronic circuits.

Resistors oppose the flow of electricity, and they all have a ''nominal resistance value''. If you look at most resistors, however, you’ll see no numbers on their bodies. Resistors were being manufactured before the technology existed to print text small enough to be seen clearly on their sides; to denote the nominal resistances, the '''resistance color code''' was born. This allows you to very quickly read the nominal resistance (and '''tolerance''') of a resistor. (The tolerance describes how accurate the resistor’s value is. If a 100Ω resistor’s tolerance is 5%, then its ''measured resistance'' is guaranteed to be between 95Ω and 105Ω.)

1000Ω ± 5%

You will begin to encounter more complicated circuits in your electronic escapades, such as the following two:

The resistances of resistors in series will just add linearly, so:

In the first example above, this works out to: