Transistor Calculations

hello im trying learn transistors. can use them more efficiently. way i've been doing things trial , error method. what  im looking how calculate gain/bias voltage , of best methods use them. know part of how use them prob varies depending on application of them. yea have read bit them keep getting calculations complicated. , mean don't explain numbers or don't describe letters in the  calculation. vc , equals what? voltage collector not simple figure out. i've seen people beta of transistor. , others beta not right way go due betas change temp , other factors. im kinda getting mixed signals. lol pun intended straight forward explanation.  time in reading monstrosity of post. grammars. transistor im using cheap o   npn 2n3904 , pnp im using 2n3906. , side note don't know how read hfe meaning on data sheet. don't means besides beta or numbers makes no sense me im stuupo.

beta or hfe current gain of transistor. npn transistor, when emitter grounded, if induce current flow base (call base current, ib), collector try sink beta times (or hfe times) greater current (call ic).


base-emitter junction looks pretty diode. induce current base, use resistor. resistor has resistance, call rb. connect 1 side of resistor base, , side voltage source. voltage source has voltage vs.

base current can calculated follows:

ib = (vs - 0.6) / rb

0.6 volts subtracted because base-emitter diode, , diode has voltage drop of 0.6v when  conducts.

thus, collector can sink current

ic = hfe * ib = hfe * (vs - 0.6) / rb

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