A buffer opamp is commonly used as a middle stage, between two circuits, to isolate the circuits from each other. The output voltage of a buffer opamp is inputted directly into the inverting terminal of the opamp. A buffer opamp has a voltage gain of one, also known as a unity gain. The buffer opamp does, however, have a high current gain. Buffer opamps prevents loading because they have a high input impedance and a low output impedance.