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Hi,
R9 and R10 set the DC operating point.
With the adjustment of R10 combined with C4 you control the AC gain.
Klaus
Hi,
just from the AC view: Consider the capacitor as zero impedance.
If the pot R10 is adjusted to the bottom then the emiter AC impedance is 130 Ohm + 5000 Ohm = 5130 Ohm. --> Low gain
If the pot R10 is adjusted to half value then the emiter AC impedance is 130 Ohm + 2500 Ohm = 2630 Ohm. --> Medium gain
If the pot R10 is adjusted to the top then the emiter AC impedance is 130 Ohm --> High gain
The higher the emitter impedance the lower the gain.
Klaus
Hi,
For sure not.
Klaus
Hi,
if you remove C4 then the center tap of R10 is unconnected. --> impossible to adjust anything with R10.
Klaus
What I mean by removing c4 is to connect the center tap directly to tail of 5k pot.
Hi,
As you recognized before: C4 is high impedance for DC.
If you now short C4 the path is low impedance for DC. So a change of R10 changes the DC operation point.
Klaus
So in conclusion, C4 is placed tbere to control the impedance since by the a.c signal, but not the resistance seen by d.c so that when the pot is adjusted the d.c operating point is not affected. Am I correct?
Can you tell me what are the feedback path's components since I do not see any?