Editing Electricity (section)

===Electric circuits===
{{Main|Electric circuit}}
[[File:Ohms law voltage source.svg|thumb|A basic [[electric circuit]]. The [[voltage source]] ''V'' on the left drives a [[Current (electricity)|current]] ''I'' around the circuit, delivering [[electrical energy]] into the [[resistor]] ''R''. From the resistor, the current returns to the source, completing the circuit.|alt=refer to caption]]

An electric circuit is an interconnection of electric components such that electric charge is made to flow along a closed path (a circuit), usually to perform some useful task.<ref>{{cite book|chapter-url=https://openstax.org/books/physics/pages/19-2-series-circuits |title=Physics |publisher=OpenStax |first1=Paul Peter |last1=Urone |display-authors=etal |year=2023 |isbn=978-1-951693-21-3 |page=612 |chapter=19.2: Series Circuits}}</ref>

The components in an electric circuit can take many forms, which can include elements such as [[resistor]]s, [[capacitor]]s, [[switch]]es, [[transformer]]s and [[electronics]]. [[Electronic circuit]]s contain [[Active device|active component]]s, usually [[semiconductor]]s, and typically exhibit [[non-linear]] behaviour, requiring complex analysis. The simplest electric components are those that are termed [[passivity (engineering)|passive]] and [[linear]]: while they may temporarily store energy, they contain no sources of it, and exhibit linear responses to stimuli.<ref name=Alexander>{{Citation | last1 = Alexander | first1 = Charles | last2 = Sadiku | first2 = Matthew | title = Fundamentals of Electric Circuits | publisher = McGraw-Hill | year = 2006 | edition = 3, revised |isbn =978-0-07-330115-0}}</ref>{{rp|15–16}}

The [[resistor]] is perhaps the simplest of passive circuit elements: as its name suggests, it [[Electrical resistance|resists]] the current through it, dissipating its energy as heat. The resistance is a consequence of the motion of charge through a conductor: in metals, for example, resistance is primarily due to collisions between electrons and ions. [[Ohm's law]] is a basic law of [[circuit theory]], stating that the current passing through a resistance is directly proportional to the potential difference across it. The resistance of most materials is relatively constant over a range of temperatures and currents; materials under these conditions are known as 'ohmic'. The [[ohm]], the unit of resistance, was named in honour of [[Georg Ohm]], and is symbolised by the Greek letter Ω. 1&nbsp;Ω is the resistance that will produce a potential difference of one volt in response to a current of one amp.<ref name=Alexander/>{{rp|30–35}}

The [[capacitor]] is a development of the Leyden jar and is a device that can store charge, and thereby storing electrical energy in the resulting field. It consists of two conducting plates separated by a thin [[Insulator (electricity)|insulating]] [[dielectric]] layer; in practice, thin metal foils are coiled together, increasing the surface area per unit volume and therefore the [[capacitance]]. The unit of capacitance is the [[farad]], named after [[Michael Faraday]], and given the symbol ''F'': one farad is the capacitance that develops a potential difference of one volt when it stores a charge of one coulomb. A capacitor connected to a voltage supply initially causes a current as it accumulates charge; this current will however decay in time as the capacitor fills, eventually falling to zero. A capacitor will therefore not permit a [[steady state]] current, but instead blocks it.<ref name=Alexander/>{{rp|216–20}}

The [[inductor]] is a conductor, usually a coil of wire, that stores energy in a magnetic field in response to the current through it. When the current changes, the magnetic field does too, [[electromagnetic induction|inducing]] a voltage between the ends of the conductor. The induced voltage is proportional to the [[Time derivative|time rate of change]] of the current. The constant of proportionality is termed the [[inductance]]. The unit of inductance is the [[Henry (unit)|henry]], named after [[Joseph Henry]], a contemporary of Faraday. One henry is the inductance that will induce a potential difference of one volt if the current through it changes at a rate of one ampere per second. The inductor's behaviour is in some regards converse to that of the capacitor: it will freely allow an unchanging current but opposes a rapidly changing one.<ref name=Alexander/>{{rp|226–29}}