Editing Two-port network (section)

{{short description|Electric circuit with two pairs of terminals}}
{{distinguish|Quadrupole}}

[[File:Two Port Circuit.svg|thumb|180px|right|Figure&nbsp;1: Example two-port network with symbol definitions. Notice the '''port condition''' is satisfied: the same current flows into each port as leaves that port.]]

In [[electronics]], a '''two-port network''' (a kind of '''four-terminal network''' or '''quadripole''') is an [[electrical network]] (i.e. a circuit) or device with two ''pairs'' of [[Terminal (electronics)|terminal]]s to connect to external circuits. Two terminals constitute a [[port (circuit theory)|port]] if the [[Electric current|current]]s applied to them satisfy the essential requirement known as the port condition: the current entering one terminal must equal the current emerging from the other terminal on the same port.<ref name=Gray>Gray, §3.2, p.&nbsp;172</ref><ref name=Jaeger>Jaeger, §10.5 §13.5 §13.8</ref>  The ports constitute interfaces where the network connects to other networks, the points where signals are applied or outputs are taken.  In a two-port network, often port 1 is considered the input port and port 2 is considered the output port.

It is commonly used in mathematical [[Network analysis (electrical circuits)|circuit analysis]].