Yes degeneration is feedback over a single device. However, that misses the point. Folks seem to do a pretty nice job optimising global loop negative feedback (eg use a lot or not at all) but degeneration is oft applied willy nilly. One of the points I made above from a few years ago, is that degenerating a push pull stage will increase H3 for sure. This is not a major issue because you can always wrap enough gnfb to swamp it.
Still, I try to reduce my use of degeneration unless it makes for very convenient operating point or biasing - in which case you just grit your teeth and do it.Quite a lot like how we pump the nfb signal into a LTP differential stage knowing full well that in doing so, we inject unnecessary common mode errors into the amp. It's just too darn handy... so we just keep doing it...
Because it works. Global negative feedback has a simple beauty to it. Perhaps that is the problem, it's hard to accept what it does because in some ways it can seem counter intuitive....I get that..still works though
Alexiss - please show the circuit and attach the .asc
few have the patience to try to match your verbiage to modify some circuit they have to search for, possibly get wrong
with a pic of each circuit simmed and the .asc for them it becomes easier to follow or test your results
few have the patience to try to match your verbiage to modify some circuit they have to search for, possibly get wrong
with a pic of each circuit simmed and the .asc for them it becomes easier to follow or test your results
sometimes idealized cases can be clearer
Spice ideal Behavioral sources with "square law" equation and no feedback vs degeneration type feedback:
feedback around a square law device with only 2nd order open loop distortion gives all orders of harmonics in the feedback output - whether the feedback is local degeneration or not
Because it works. Global negative feedback has a simple beauty to it. Perhaps that is the problem, it's hard to accept what it does because in some ways it can seem counter intuitive....I get that..still works though
I always get a chuckle when someone declares negative feedback cannot work, then gets on his/her bike and rides off, which is impossible without negative feedback, the while thinking about a coming plane trip, which plane would fall out of the sky without negative feedback, and then getting home plugging his sound system in the outlet supplied by a nuclear power plant that would explode if it were not for negative feedback. Blindness is a mental state.
Jan
To this topic I have found old but very interesting statements - go to the PDF files in post #82 under
https://www.diyaudio.com/forums/sol...ooks-overview-google-books-9.html#post6707846
https://www.diyaudio.com/forums/sol...ooks-overview-google-books-9.html#post6707846