Kirchhoff circuits: definitions, constitution, general laws
Linear electrical circuits

This article deals with permanent, causal, linear electrical circuits with localized constants. This assumes that signal propagation does not interfere with the circuit, i.e. that the wavelength of signals passing through the circuit is large relative to its dimensions.

The various magnitudes of the circuit (time-dependent variables of the system) are voltages (potential differences between two points in the circuit expressed in volts) or (and) currents (expressed in amperes) flowing in the circuit branches (incidentally the electrical charge carried by the armatures of a capacitor or the magnetic flux produced by a coil). Actions are also currents or (and) voltages.