where is the sheet resistance of the material having units (known as “ohms per square”). This expresses that the resistance of a square conductor is independent of its absolute size. The ratio L/W is refered as the number of squares of wire and to obtain the resistance of a wire simply multiply the sheet resistance with the number of squares.

Using the above concepts one can calculate the resistance of transistors and inverters. Consider the following n-type transistor in Fig 4.2 with channel length . and channel width . This channel has three squares in series and thus the resistance of the channel will be 3 .