I got this signal coming from a source. Vpp = 0.65V.
This signal feeds the non inverting input of an opamp (TL974).
I supply the opamp with +5V and -5V.
The circuit is this one :
I want to amplify the signal with a gain of 3, so I choosed
Rf = 2000R
R2 = 1000R
So that G = 1 + 2 = 3
The problem is that I don t get an AC output signal but this :
Notice that when I feed the opamp with a positive AC signal (with amplitude from 0 to 0.65V rather then -0.325 to +0.325), I get the amplified positive AC signal at the output (with amp from 0 to 2V).