Hippynerd:
I think i understand the basics of the calculations, but it would be nice to understand why the parts are needed.
Which parts? Are we discussing the common emitter circuit?I also dont like the guessing part of the calculation, it seems to me that the part will likely behave about the same under similar conditions for most people.
It's not a "guess". You have to start somewhere. Having only the least is a good start, if there's more (as in more beta, as may be likely) then it only gets better. The circuit will not be a worse performer for the transistor's having more beta (gain) than anticipated.It seems like it should be easy to look that up in a chart or graph, and get close with your calculations, but I wasnt able to do that, I had to test things, before I could get in the ballpark.
How can I know where you're losing the plot? You haven't shown your work.I can't see what's going on in your schematics; they're pretty free-form, difficult to follow.