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I´m trying to figure out the transfer function of the attached op amp circuit. I came to the conclusion that v_out = - v_in as as the two resistors in the upper path are equally sized, and the non inverting input is on ground potential. However this is a task from one of our exams which I try to solve and it seems that my solution isn`t right according to the following tasks, however I got no solutions to this exam. Do I miss something?
Kind Regards
Marc
Your conclusion that Vout = - Vin is correct.
Capacitor C and resistor R2 are just there to confuse you. As there is no current flowing into (or out of) the + input of the opamp, Vin+ = 0
The opamp will try to make Vin- = 0 as well if possible. Let's assume the opamp can manage that so we assume Vin- = 0
That means the current Iin = Vin / Rin with In flowing in the direction as shown. This Iin cannot flow into the opamp's - input, all of it has to go through the other resistor R1. The left side of R1 will be at 0 V, the current will flow from left to right and that means that Vout has to be negative with a value of Vout = Iin * R1.
So Vout = - Vin.
