I'm an electrical engineering student that wants to measure DC voltage from a solar panel that outputs a maximum of 40VDC. I came here from the EE Times article (Difference amplifier measures high AC voltage without heat | EE Times).
I have simulated in Multisim a circuit like the one presented in the FUNCTIONAL BLOCK DIAGRAM of the datasheet (http://www.analog.com/media/en/technical-documentation/data-sheets/AD629.pdf) using Multisim's 3T_Virtual Op-Amp model. It kind of behaves like it should (reduce voltage by 1/20) but I don't know how can I have the most important feature, that is to accurately measure large DC signals. I was thinking of using a 741 for the job, but I'd like to know which other amplifier can I use in order to accomplished what I have described.
PS: I'm asking this because I can't find the AD629 in my country and buying it overseas its too expensive for me, I want to know if it's possible for me to recreate its behavior.