I came across a sentence that " if the DC base current has to be 10 times the signal current....".I could not understand, what is DC base current as I have just read about Input current and Output current? And also what quantity (like current gain{beta}, ratio of current through collector and current through emitter, etc.) is the mentioned statement asking for?
Asked
Active
Viewed 335 times
3
-
The sentence is relevant if you're amplifying AC, not DC. It keeps the AC analysis simple because the signal has very little effect on the (DC) bias conditions. – May 22 '20 at 16:58
1 Answers
0
If the total base current is denoted with \$i_B(t)\$, and if the time average value (DC value) of \$i_B(t)\$ is denoted with \$I_B\$, then denote the AC (signal) base current as
$$i_b(t) = i_B(t) - I_B$$
and the sentence you came across can be written as "if \$I_B\$ has to be about \$10\cdot i_b(t)\$..."
Alfred Centauri
- 26,502
- 1
- 25
- 63