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When i look at the other schematics i see emiter capacitor and resistor, but i dont have any.
That can make my amp unstable, so i dont know if i should improve anything?...
Is it working? If yes, don't bother
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In your solution, you want to have like 6V at the output 270R resistor with 0V~ input. (So when the input voltage is negative, your transistor have some space to close.) This means that bias current trough AC176 should be 6V/270R = 22,2mA.
By a datasheet, h
21e (=gain) of AC176 should be in range 50 - 250. And your adjustment of bias point (by the 100k trimmer) is amplified by this number too.
Since the voltage drop over BE of transistor and h
21e can slightly
change over time and with temperature, this amp can move from it's bias point quite quickly (it won't be unstable, but it will disort one half of the signal).
The resistor in emiter actively reduce the h
21e. So even with temperature change, bias point will stay at right place. This would ofc. reduce gain of whole amp. That is why you also add an capacitor, which acts like "short" for AC signal. Anything with a higher frequency will have the full h
21e, but DC bias will have reduced h
21e.