Editing Operational amplifier (section)

{{short description|High-gain voltage amplifier with a differential input}}

{{Infobox electronic component
| name = Operational amplifier
| image = Ua741 opamp.jpg
| caption = The μA741, a popular early integrated op amp
| type = [[Discrete circuit]]<br/>[[Integrated circuit]]
| working_principle = 
| invented = [[Karl D. Swartzel Jr.]]
| first_produced = 
| pins = {{ubl|'''V<sub>+</sub>''' non-inverting input
  |'''V<sub>−</sub>''' inverting input
  |'''V<sub>out</sub>''' output
  |'''V<sub>S+</sub>''' positive power supply<ref group="nb" name="ps">The power supply pins (''V''<sub>S+</sub> and ''V''<sub>S−</sub>) can be labeled in different ways (''See [[IC power supply pins]]''). Often these pins are left out of the diagram for clarity, and the power configuration is described or assumed from the circuit.</ref>
  |'''V<sub>S−</sub>''' negative power supply<ref group="nb" name="ps" />}}
| symbol = [[File:Op-amp symbol.svg|250px]]
| symbol_caption = Circuit diagram symbol for a representative op amp. Pins are labeled as listed above.
}}

An '''operational amplifier''' (often '''op amp''' or '''opamp''') is a [[direct coupling|DC-coupled]] [[Electronic component|electronic]] [[voltage]] [[amplifier]] with a [[differential input]], a (usually) [[Single-ended signaling|single-ended]] output,<ref>{{cite web |url=http://www.maxim-ic.com/appnotes.cfm/an_pk/1108 |id=Maxim Application Note 1108 |title=Understanding Single-Ended, Pseudo-Differential and {{Sic|hide=y|Fully|-}}Differential ADC Inputs |archive-url=https://web.archive.org/web/20070626153413/http://www.maxim-ic.com/appnotes.cfm/an_pk/1108 |archive-date=2007-06-26 |access-date=November 10, 2007}}</ref> and an extremely high [[gain (electronics)|gain]]. Its name comes from its original use of performing [[mathematical operations]] in [[analog computers]]. 

By using [[negative feedback]], an [[Op amp circuits|op amp circuit]]'s characteristics (e.g. its gain, input and [[output impedance]], [[bandwidth (signal processing)|bandwidth]], and functionality) can be determined by external components and have little dependence on [[temperature coefficient]]s or [[engineering tolerance]] in the op amp itself. This flexibility has made the op amp a popular building block in [[analog circuit]]s.

Today, op amps are used widely in consumer, industrial, and scientific electronics. Many standard [[integrated circuit]] op amps cost only a few cents; however, some integrated or hybrid operational amplifiers with special performance specifications may cost over {{Currency|amount=100|code=US}}.<ref>{{cite web |title=Apex OP PA98 |url=http://www.digikey.com/product-detail/en/PA98/598-1337-ND/1761961 |access-date=8 November 2015 |quote=APEX PA98 Op Amp Modules, Selling Price: $207.51 |url-status=dead |archive-url=https://web.archive.org/web/20160101094650/http://www.digikey.com/product-detail/en/PA98/598-1337-ND/1761961 |archive-date=1 January 2016 }}</ref> Op amps may be packaged as [[Electronic component|components]] or used as elements of more complex [[integrated circuit]]s.

The op amp is one type of [[differential amplifier]]. Other differential amplifier types include the [[fully differential amplifier]] (an op amp with a [[Differential signalling|differential]] rather than single-ended output), the [[instrumentation amplifier]] (usually built from three op amps), the [[isolation amplifier]] (with [[galvanic isolation]] between input and output), and [[negative-feedback amplifier]] (usually built from one or more op amps and a resistive feedback network).