2.1h.3iv Difference Amplifier

Difference Amplifier

A difference amplifier is an op-amp configuration that subtracts two voltages in addition to adding a gain to each of them, such that $V_o=G_1{V}_1+G_2{V}_2$, where $G_1=-\frac{R_f}{R_1}$ and $G_2=\left(\frac{R_4}{R_3+R_4}\right)\left(\frac{R_1+R_2}{R_1}\right)$.