Unbroken path along which an electric current may flow. A simple circuit
consists of a Voltage source, such as a Battery (see Cell) or a Generator, whose terminals are connected to those of a circuit element, such as a Resistor, through which Current can flow. More complex circuits include additional sources or elements and
perhaps Switches, so interconnected that, when appropriate switches are closed, each element
is included in a closed path that also contains a source. The effective Resistance of two series-connected (see Series Circuit) resistors is the sum of the individual resistances. The effective Conductance (reciprocal of resistance) of two parallel-connected resistors is the sum of
the individual conductances.