a circle or arc (part of a circle) that is the locus of the end points of vectors representing some electrical magnitude in a complex plane. A clock diagram is used in electrical and radio engineering to study the variation of electric cur-rent intensity and of voltage, power, and resistance as functions of a varying parameter (for example, ohmic resistance, inductance, or capacitance).
A clock diagram graphically shows the variation of the absolute value and phase of a given quantity according to the variation of an independent parameter. Clock diagrams can be constructed only for linear circuits that have active and reactive elements and usually only if the amplitude and phase of the electromotive force of the power supply are constant. They can be constructed for any devices whose equivalent circuits reduce to two-terminal networks or quadripoles. Clock diagrams are used in lines with distributed parameters for the graphic determination of input impedances (or conductances) and to analyze the conditions of operation of the lines.