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Common Emitter Audio Amplifier Question


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I'm tring to build an audio amplifier. I decided to use a basic common emitter amplifier circuit as a starting point and added a speaker to it.

62QI5.png

I have some questions about the circuit.

1-) Is 2n2222 ok for this circuit?

Results of DC analysis: Vce = 10.06V and Ic = 1.26mA (I guess, these values will be used for choosing the transistor.)

2-) What's the output voltage of a standart mp3 player? Can it be 300mVp as I read somewhere?

3-) When I assume ß = 150 and input = 300mVp , the output is -2,13Vp . I guess it gives 1w power to speaker. Is there something wrong?

4-) Is connecting speaker parellel to output R ok?

Thank you..

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  • 4 months later...

for building the audio amplifier u need to use a power BJT class b push pull mode for obtaining good amplification.

No.
A class-B amplifier produces horrible crossover distortion. Audio amplifiers use a class-AB output stage.

I simulated the circuit with an input of 1V peak.
With a 12k ohm load the output is pretty good (almost 5V peak).
But the 4 ohm speaker seriously overloads the simple circuit and reduces the output to almost nothing (4mV peak).

post-1706-14279144495637_thumb.png

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