Editing Amplifier (section)

=== Unilateral or bilateral ===
An amplifier whose output exhibits no feedback to its input side is described as 'unilateral'. The input impedance of a unilateral amplifier is independent of load, and output impedance is independent of signal source impedance.<ref>{{Cite web|url=http://www.microwaves101.com/encyclopedias/active-directivity-of-amplifiers|title=Microwaves101 {{!}} Active Directivity of Amplifiers|last=Administrator|website=www.microwaves101.com|access-date=2016-06-20}}</ref>

An amplifier that uses feedback to connect part of the output back to the input is a ''bilateral'' amplifier. Bilateral amplifier input impedance depends on the load, and output impedance on the signal source impedance.
All amplifiers are bilateral to some degree; however they may often be modeled as unilateral under operating conditions where feedback is small enough to neglect for most purposes, simplifying analysis (see the [[common base]] article for an example).{{Cn|date=December 2024}}