I like how he goes back and forth btwn the media elements(chalkboard, lightbox?, and the physical application) to explain how stuff like this works. I like the physical applications the best and I helps me learn this so much easier..... Wish the electronics class @MU Hamilton campus did their classes like this guy when I went there in the 90's.
If you draw the root locus of G=-A/((s+k)*(s-k)) using MATLAB, you get the branches in different position than shown in the video. The rlocus looks like: I have the impression he chose not to comment about the negative sign in the numerator. Am I missing anything?
I think when you put it in matlab like that it assumes your system has positive feeback and therefore the root locus doesn't look like what the video shows. Im not sure why he showed the block diagram like that. Maybe for simplicity? I think the assumption is that the amplifier is wired up in such a way as to provide negative feedback. Otherwise the ball wouldn't be stable.
