Hello, I have two questions today Reading ahead of my class, I noticed that we were coming up on frequency response. My book kept discussing midrange gain, but it doesnt define it anywhere. I tried looking online and I couldn't find a good definition there either. The only thing I could find that was similar was about midrange frequencies (not midrange gain). From the picture in the book, it looks like midrange is defined as 0Hz to critical frequency which is about 3dB less than Aol. But that doesnt really help me with midrange gain. In my research I did noticed that midrange gain is the range of frequencies in which I CAN use the formulas I have learned (such as -Rf/Ri, or Rf/Ri + 1). I wasn't sure why they didnt work for frequencies passed this "critical frequency" which brings me to my first question. This got me thinking about how Op Amps can amplify DC (since this wasn't explicitly discussed in my text either). So doing research I found that Op Amps are decoupled. This confused me because I remember back from my freshmen electronics classes that decoupling meant to un-couple/bypass... to eliminate (though not completely) an AC signal while passes DC. Or I always remembered it as eliminate voltage spikes. So my question comes out of the confusion in that the decoupled Op Amp amplifies both DC AND AC signals. With that said, I know that Op Amps have a bandwidth after which they are not as efficient at amplifying (the gain changes). Is this because... Since the Op Amp is decoupled, it can amplify low frequencies (0Hz) and lower AC frequencies (relatively, based on the capacitor due to Xc). Once a certain frequency is reached, the decoupling capacitors begin to filter/begin working as a rectifier? I guess I am confused as to how a dc coupled capacitor can allow ac through (unless my explanation above is somewhat correct... that there is a range from 0Hz to some relatively low frequency that can pass while higher frequencies begin to get blocked more and more). I understand how rectifiers work, so this makes sense to me (I just cant find a website or text in my book to verify that my logic is ok) Also, I was confused why midrange is from 0Hz to the critical frequency when this range is clearly not the midrange of the range of frequencies that exist. Seemed a bit confusing. Seems like it should be called "low range" Finally, in lab, we are doing things like measuring slew rate or voltages at various pins. We built a diff Amp, saw how an inverting amp inverted a signal... etc Does anyone know of anything cool I can do with my op amp? Are there any cool labs/ projects I can build for my own knowledge/curiosity? I tried looking on youtube, but a lot of the labs there are the same thing... proving theory. "This is a slew rate now go look at what a slew rate looks like on a scope in real life". "This is what a buffer (VF) does. No go look at what a buffer does in real life." We keep putting the Op Amp in a circuit by itself and putting jumpers in at different points to see its affects. I actually want to build a circuit where my 741 does something (rather than constantly, week after week, prove quantities that are in the data sheet). I am very curious!! Thank you so much! As always!