Open-loop gain: Difference between revisions

Revision as of 10:51, 17 December 2009

Revision as of 14:33, 23 March 2010

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{{Unreferenced stub|auto=yes|date=December 2009}}

The '''open-loop [[gain]]''' of an [[operational amplifier]] is the gain obtained when no [[feedback]] is used in the [[electrical network|circuit]].

Open loop gain is usually exceedingly high; in fact, an ideal operational amplifier has infinite open-loop gain. Typically an op-amp may have an open-loop gain of around <math>10^95</math>. Normally, feedback is applied around the op-amp so that the gain of the overall [[electrical network|circuit]] is defined and kept to a figure which is more usable. However the very high gain of the op-amp enables considerable levels of feedback to be applied to achieve required performance. The open-loop gain of an operational amplifier falls very rapidly with increasing [[frequency]]. Along with [[slew rate]], this is one of the reasons why operational amplifiers have limited [[Bandwidth (signal processing)|bandwidth]].

A_OL = V_out/(V⁺ - V^-)