This is an update on my previous question.
As Hearth suggeste, I changed to DC coupling on my scope.
This is what I got:
That's a clear change. Not a perfect square waves but I guess it is because of the 200MKF capacitors at the end of those transistors.
I was assigned to fix the generator (square wave function didn't work before.)
I had to change two 200MKF capacitors. The lowest I could get was 220MKF (I guess that's the reason behind the not so perfect squares,) and I had to connect the square wave amplifier to the output.
IWhen I thought I had finished the job, the professor told me about not getting square waves at 1V 1Hz (first picture.) I can't really understand if he didn't know that scope was set to AC coupling or he wanted it to be on AC coupling.
Is it possible to get square wave at that voltage and frequency with AC coupling? If yes, how? (Best guess using compensator.)
Is it really that distorted because I used 220MKF instead of 200MKF, or ar there any other possible reasons? How can I improve it?
What is the difference between AC and DC coupling?
What I understood from the internet is that DC coupling lets the signal through to the scope directly whilst AC coupling uses a high-pass filter - a capacitor, which removes some frequencies, and at low frequencies I get s distorted square wave (picture 1), but at higher frequencies that capacitor acts like resistor, thus increasing frequency, makes wave more like square. Is this thinking anywhere near true? If not let me know how it really ist.
When and why do I have to use AC or DC coupling?
I really want to understand science behind all of this.