In order for voltage to differ between parallel-connected components, the potential energy of charge carriers would have to somehow appear and disappear to account for lesser and greater voltages. The principle of voltage being the same across all parallel-connected components is (also) an expression of a more fundamental law of physics: the Conservation of Energy, in this case the conservation of specific potential energy which is the definition of voltage. This means there can be only one value of voltage anywhere in the circuit, the exact same voltage for all components at any given time. “Equipotential” simply means “at the same potential” which points along an uninterrupted conductor must be. The defining characteristic of a parallel circuit, by contrast, is that all components share the same two equipotential points.
It also means that the sum of all voltages dropped by load devices must equal the sum total of all source voltages, and that the total resistance of the circuit will be the sum of all individual resistances:
#SERIES VS PARALLEL SERIES#
Series circuits are defined by having only one path for current, and this means the steady-state current in a series circuit must be the same at all points of that circuit. It would be the equivalent of having different rates of water flow at different locations along one length of pipe. In order for current to have different values at different points in a series circuit indefinitely, electric charge would have to somehow appear and disappear to account for greater rates of charge flow in some areas than in others. The principle of current being the same everywhere in a series circuit is actually an expression of a more fundamental law of physics: the Conservation of Charge, which states that electric charge cannot be created or destroyed. This means there can be only one value for current anywhere in the circuit, the exact same current for all components at any given time. The defining characteristic of a series electrical circuit is it provides just one path for current. The two circuit types are shown here, with squares representing any type of two-terminal electrical component:
These rules fall neatly into two categories: series circuits and parallel circuits.
In addition to Ohm’s Law, we have a set of rules describing how voltages, currents, and resistances relate in circuits comprised of multiple resistors.