Differential amplifier
A differential amplifier is a type of electronic amplifier that amplifies the difference between two input voltages but suppresses any voltage common to the two inputs. It is an analog circuit with two inputs V in − {\displaystyle V_{\text{in}}^{-}} and V in + {\displaystyle V_{\text{in}}^{+}} and one output V out {\displaystyle V_{\text{out}}} , in which the output is ideally proportional to the difference between the two voltages: V out = A ( V in + − V in − ) , {\displaystyle V_{\text{out}}=A(V_{\text{in}}^{+}-V_{\text{in}}^{-}),} where A {\displaystyle A} is the gain of the amplifier.