That is, a linear circuit is a circuit in which (1) the output when a sum of two signals is applied is equal to the sum of the outputs when the two signals are applied separately, and (2) scaling the input signal x ( t ) {\displaystyle x(t)} by a factor h {\displaystyle h} scales the output signal F ( x ( t ) ) {\displaystyle F(x(t))} by the same factor.