SneaKSz
Member
Hello all,
I was reading an audio amplifier book (by bob cordell) and he said the β8=100 and β10=50, the collector of Q4 would see 100*50*8=40kΩ.
I understand that this would be the case if R11 wouldn't be included and R13 is low and left behind, but R11 infects the input impedance.
Why can the input impedance be calculated by using the formula above?
Doesnt Q9 and Q11 also being active, not infect the collector impedance of Q4?
And finally shouldn't Q5 also be taken into account when determining the collector impedance of Q4?
**broken link removed**
These are some questions I've been banging my head over lately.
Hopefully you guys can point me out in the right direction!
kind regards !
I was reading an audio amplifier book (by bob cordell) and he said the β8=100 and β10=50, the collector of Q4 would see 100*50*8=40kΩ.
I understand that this would be the case if R11 wouldn't be included and R13 is low and left behind, but R11 infects the input impedance.
Why can the input impedance be calculated by using the formula above?
Doesnt Q9 and Q11 also being active, not infect the collector impedance of Q4?
And finally shouldn't Q5 also be taken into account when determining the collector impedance of Q4?
**broken link removed**
These are some questions I've been banging my head over lately.
Hopefully you guys can point me out in the right direction!
kind regards !
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