anyone can give me audio amplifier circuit using transistor (Pnp or Npn), plz indicate the values of components as well

 

Hello,

We can not give you complete schematics at the homework section.
I can give you info on amplifiers:
http://www.educypedia.be/electronics/amplifiers.htm

Greetings,
Bertus

 

I don't need such info, plz help me I am very frustrated with this project

 

Hello,

Show us what you got.
That way we can help you.

Bertus

 

do you have workbench???

http://www.ziddu.com/download/9229376/4.rar.html

link contains the circuit diagram, download is in rar

 

Look at all PNP audio power amplifier.
And we don't use workbench here. Post your diagram in PNG or JPG.

 

here is the circuit

the problem is that the output signal is not amplifying, it has same amplitude as input signal

 

Look at all PNP audio power amplifier.
And we don't use workbench here. Post your diagram in PNG or JPG.

"And we don't use workbench here" What do you mean by that? Every member in this forum is free to use the tool he/she prefer. I use Altium Designer.

 

if you don't use workbench then make this circuit in altium and analyze it

 

Your extremely simple circuit is missing a speaker. So it has no power supply and has no load. Connect an 8 ohm speaker in parallel with the oscilloscope and see what happens.
The speaker and the second transistor will get hot.

 

I have used signal generator instead of microphone and oscilloscope instead of speaker

 

Hello,

An osciloscope has most times an input resistance of 1 M or higher.
You are testing the circuit with this resistance.
Try a resistor of 1K accross the inputs of the scope and see what happens.

Bertus

 

Hello,

An osciloscope has most times an input resistance of 1 M or higher.
You are testing the circuit with this resistance.
Try a resistor of 1K accross the inputs of the scope and see what happens.

Bertus

I think then OP say a scope he/she is refering to a virtual scope in the software
Edit: I also think the OP should apply some voltage to the transistor base bias network. Something is wrong with the schematics

 

According to your schematic.


Your osciloscope is being used as a series resistance from the positive battery terminal. So you have no positive supply to the circuit itself.

The osciloscope needs to be connected to ground and one terminal to the collector of the transistor stage,

You need to put a collector resistor in the collector loop, or you will not develop a voltage at the output with no collector resistor.

Essentialy what your reading is the signal itself coming through the top resistor from the signal generator. Bypassing the trasnsistors all together.

Here is how to hook up the oscilloscope for input and output readings with respect to a common signal ground.

With no load.

 

thank you soo much Hobbyist now the only problem left is that my signal at channel B is not amplifying, I mean its amplitude is same as the signal at channel A, how I should increase the amplitude of the output signal???

 

Here is your circuit, with the same values you used, note the 10 ohm collector resistor, and all the settings on the osciloscope, and functrion generator. As well as the circuit configuration.

 

hats off to you, im very happy from you.

 

Notice that the extremely simple class-A "amplifier" has a voltage gain of only 10.
If you use a microphone then you must add a preamp with a voltage gain of about 20.

 

ok one more question if you can see in the diagram the input signal and output signal are out of phase, what should i do to make the phase of both the signals same???

 

hey guru I have to show the waveform first to my professor and then my job will be to implement this circuit on bread board and I will have to use mic as input signal and speaker as output, so tell me how many ohms speaker I should select and which type of mic???