The nomographic usage is deprecated. The visualization utility remains.

The Smith chart is a graphical tool for solving problems involving complex impedances, admittances, and transmission lines. It maps complex reflection coefficients onto a circular diagram containing curves of constant resistance and reactance. Engineers can use the chart to visualize how impedance changes along a transmission line, determine reflection coefficients and standing-wave ratios, and design impedance-matching networks. Operations that would otherwise require complex-number calculations can be performed geometrically by moving around the chart. Developed by engineer Phillip H. Smith, it remains a symbol of radio-frequency engineering. It is used in RF engineering, antenna design, and transmission-line analysis.