Hippynerd:
I still dont have any idea how to figure out how to figure out the gain/hfe/beta for the calculations,
Then you haven't been reading any of my posts.
Hippynerd:
It seems to me, that should be as simple as looking it up in a table on the datasheet.
Again, (I have posted this twice before) beta is not a firm figure, there's a range, but a minimum guaranteed is always specified - that's what you work with. Reconcile yourself to the fact that the way it's done and how you want it are two different matters.
Hippynerd:
The beta numbers 10 and 100 came from 2 different individuals, when I asked them where on the datasheet can I find the right value for my uses (20-240ma at 5v).
Those numbers did not come from me.
Hippynerd:
It seems to me, that there should be a few common resistors used with 2n2222 transistors, one for 5v, and other for 12v applications. the part is only good for about 1/2 amp (mine are smt, and only good for 350ma). I would think that I would find 5v circuits all had about the same value base resistor, and 12v circuits would have a different value, but the 12v circuits would all have a similar value base resistor.
Why would you think they would be the same?
The base current required for IC up to 240mA is different than that for 100mA or 50mA. Yes, someone could set it all up for the possibility of 240mA, no matter what, but then where that's more than required it'd be over-driven like crazy. That's OK, in a political sense, but the cognoscenti will deride the unnecessary base current.
Moderator edit: unnecessary sarcasm removed