raschemmel:
Typical gain hfe for a 2n2222 is between 100 and 300. If you figure 200 then 5V-0.7V=4.3V/ [0.3A/200]=2.8k ohm for R1
.3A/200=0.0015, (gain of 200 so R1 current should 1/200th Collector current. Your calculation for R2 is ok but even though the
calculation for R1 comes out to be 2.8k ohm, I would say go ahead and use a 1 k ohm because you are already limiting the current with R2
13.8-13.2)=0.6V
0.6V /2 ohm = 0.3A0.3A/200=0.0015A
(5V-0.7V=4.3V/ [0.3A/200]=2.8k ohm for R1)
Anything between 1 k and 2,8 k is fine.
This is the answer i was searching for! thank u very much for writing it out, it get the math now.
i didnt see a "thanks" button, or anything.. or ida def engaged!
Thanks again!