1. The problem statement, all variables and given/known data For the following circuit, sketch v2/v1 as a function of R4, if R1=R2=R3=R5=R. Also explain the behaviour of the circuit when R4=R/2. 2. Relevant equations 3. The attempt at a solution After solving the circuit, i came up with v2/v1=2R4/(2R4-R). Now, if R4=R/2 , gain=infinite, is that ok? plus, what happens, when 2R4<R?