Transmission line problems are greatly simplified if the line is terminated by an impedance equal to its characteristic impedance. Standing waves of current and voltage are then eliminated, and if losses are neglected, the input impedance, current, and voltage at all points along the line are constant. Computations for the current and voltage under these conditions are based simply on Ohm's law. In communication systems this special condition is usually considered most conducive to efficient trouble-free operation. There has long been a need for a simple means, without recourse to lengthy computations, for evaluating the impedance, current, and voltage at any chosen point along radio-frequency transmission lines in terms of specific values of the several transmission line parameters. This has led to the development of a special radio-frequency transmission-line calculator for solving many ordinary transmission-line problems.