Operational amplifier

Operational amplifier
The μA741, a popular early integrated op amp
TypeDiscrete circuit
Integrated circuit
InventedKarl D. Swartzel Jr.
Pin configuration 
  • V+ non-inverting input
  • V− inverting input
  • Vout output
  • VS+ positive power supply[nb 1]
  • VS− negative power supply[nb 1]
Electronic symbol

Circuit diagram symbol for a representative op amp. Pins are labeled as listed above.

An operational amplifier (often op amp or opamp) is a DC-coupled electronic voltage amplifier with a differential input, a (usually) single-ended output,[1] and an extremely high gain. Its name comes from its original use of performing mathematical operations in analog computers.

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

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 US$100.[2] Op amps may be packaged as components or used as elements of more complex integrated circuits.

The op amp is one type of differential amplifier. Other differential amplifier types include the fully differential amplifier (an op amp with a 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).


Cite error: There are <ref group=nb> tags on this page, but the references will not show without a {{reflist|group=nb}} template (see the help page).

  1. ^ "Understanding Single-Ended, Pseudo-Differential and Fully-Differential ADC Inputs". Maxim Application Note 1108. Archived from the original on 2007-06-26. Retrieved November 10, 2007.
  2. ^ "Apex OP PA98". Archived from the original on 1 January 2016. Retrieved 8 November 2015. APEX PA98 Op Amp Modules, Selling Price: $207.51