Common Emitter Audio Amplifier Question

[kzriwoga1]

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.

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..

 

[Hero999]

The amplifier has too higher output impedance to power a 4R speaker. You need a power amplifier. The circuit you've posted is for a signal amplifier.

 

[Kevin Weddle]

The circuit is a basic amplifier. It may not produce the desired result, unless it engineered to the specification of the MP3 player. The gain looks very low. The capacitors are the wrong value and it may need inductors or additional circuitry for linear amplification.   

 

[avinashnr2]

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

 

[audioguru2]

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).View attachment 41766