In this case, when the input is greater than zero, D1 is off, and D2 is on, so the output is zero because the other end of R 2 {\displaystyle R_{2}} is connected to the virtual ground and there is no current through R 2 {\displaystyle R_{2}} . When the input is less than zero, D1 is on and D2 is off, so the output is like the input with an amplification of − R 2 / R 1 {\displaystyle -R_{2}/R_{1}} . Its input–output relationship is the following: