Editing Voltage (section)

==Hydraulic analogy==
{{Main|Hydraulic analogy}}

A simple analogy for an [[electric circuit]] is water flowing in a closed circuit of [[pipework]], driven by a mechanical [[pump]].{{cn|date=March 2024}} This can be called a "water circuit".  The potential difference between two points corresponds to the [[fluid pressure|pressure difference]] between two points. If the pump creates a pressure difference between two points, then water flowing from one point to the other will be able to do work, such as driving a [[turbine]]. Similarly, work can be done by an [[electric current]] driven by the potential difference provided by a [[electric battery|battery]]. For example, the voltage provided by a sufficiently-charged automobile battery can "push" a large current through the windings of an automobile's [[starter motor]]. If the pump is not working, it produces no pressure difference, and the turbine will not rotate. Likewise, if the automobile's battery is very weak or "dead" (or "flat"), then it will not turn the starter motor.

The hydraulic analogy is a useful way of understanding many electrical concepts. In such a system, the work done to move water is equal to the "[[pressure]] drop" (compare p.d.) multiplied by the [[volume]] of water moved. Similarly, in an electrical circuit, the work done to move electrons or other charge carriers is equal to "electrical pressure difference" multiplied by the quantity of electrical charges moved. In relation to "flow", the larger the "pressure difference" between two points (potential difference or water pressure difference), the greater the flow between them (electric current or water flow). (See "[[Electric power#Definition|electric power]]".)