Reflection coefficients can be read directly from the chart as they are unit-less parameters. Once an answer is obtained through the graphical constructions described below, it is straightforward to convert between normalised impedance (or normalised admittance) and the corresponding unnormalized value by multiplying by the characteristic impedance (admittance). The most commonly used normalization impedance is 50 ohms. Impedance Measurements The Smith Chart The Smith Chart is a graphical computation tool developed by Dr. Normalised scaling allows the Smith chart to be used for problems involving any characteristic or system impedance which is represented by the center point of the chart.

These are often known as the Z, Y and YZ Smith charts respectively.

The Smith chart is plotted on the complex reflection coefficient plane in two dimensions and is scaled in normalised impedance (the most common), normalised admittance or both, using different colours to distinguish between them.