Audio Amplifier. Which class should I use?

[Jestin_cubetech]

of course i'm here to help . How can i help you ?

lm4702 stereo audio driver based class b amplifier is a good option.

 

[goldsmith]

Hi shayaan
Don't worry about it . i will tell you how to do it ! but at first step write AV . we will convert it to the S form . ok ?

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Hi jestin
Do you know how much power we are referring to ?

 

[Shayaan_Mustafa]

OK sir thank you sir.,

You have given me two circuits.

Voltage gain (Av)= Vo/Vi
For 1st circuit,
Av = C/Vi

For 2nd circuit,
Av = RL/Vi

 

[goldsmith]

No no no ! you are in wrong way . a guidance : as you probably know , xc=1/jwc ok ? and xl = jwl ok ? can you use the action like dividing voltage , from input to the out put ? ( are you familiar with : how to calculate impedance of a circuit ? if yes . a division between an impedance and another impedance . for example suppose that we have two resistor R1 and R2 . VR1=vout ( for instance ) .
Then vout = vin *( R1/R1+R2 ) . so you can use an action such as this , in this example . ok ?

 

[Shayaan_Mustafa]

OK so you mean I have to use voltage divider. OK I try.

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OK so you mean I have to use voltage divider. OK I try.

 

[goldsmith]

Yes , the method is the same ! but instead of R1 and R2 you will have Z1 and Z2 . ok ?

 

[Shayaan_Mustafa]

For first circuit we have two impedance, Zc(capacitor) and ZL(inductor)

Vo=(Zc)/(ZL+Zc) * Vi

Is it right sir?

If no just tell me. I want to try it myself you just guide. Don't post solution.

 

[goldsmith]

It is correct , but don't write ZC or ZL , use 1/jwc or jwl ok ? now improve it .

 

[Shayaan_Mustafa]

OK.

Vo = (1/jwC)/{(1/jwC)+jwL} * Vi

Vo = Vi/{(jwC)(1/jwC+jwL)}

Sir I don't know how to simplify it more. :S

 

[goldsmith]

Find (1/jwc ) + jwl and then multiply jwc on it !

 

[Shayaan_Mustafa]

So j and w can be squared? or can they also be cancelled out?

 

[goldsmith]

not at this time . it can be simpler but not removed simply !

 

[Shayaan_Mustafa]

Vo = {Vi}/{1/(jwL/jwC + 1/j2w2LC)}

Should it look like this?

 

[goldsmith]

see it : vi/jwc*((1+j^2*w^2*LC)/jwc ) ok ?

 

[Shayaan_Mustafa]

OK sir I got it.

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BTW: I have to go now sir. But you post what you want I will see it at morning and I will post answer. Good morning sir.

 

[goldsmith]

to simplify it ! think on J^2 ! what will be the result . and try to remove a common part ! good morning my friend ! see good dreams ! see you later .

 

[Shayaan_Mustafa]

Hello sir,

The final equation looks like,



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Hello sir,

The final equation looks like,

 

[goldsmith]

Hi shayaan
Sorry because of this delay . i came back again ! see below , please :

You understand ?

 

[Shayaan_Mustafa]

Hello sir.

I was waiting for your answer. I post my solution if you reply to my post#378. I also got the same answer in your above post. Yes I have done it.

 

[goldsmith]

But our answer are different together . see my post and your post and compare them together .