Hi all, I'm having trouble to solve an exercise about class A output stage.

This is my circuit

http://www.imagestoring.net/show.php/6472_classea.png.html

I need to calculate the VBB and I have to do it without the beta from the transistor.
My first idea was using beta with Ic / Ib = Beta and with the value of Rb I should know.
My second idea is none.. Can you give me some ideia to solve this?


All I know is :

I_CQ = Icmax/2
Icmax-> max collector current
I think I_CQ will be the current on the transistor ?!?

V_CEQ = Vcc/2
And I think V_CEQ will be the voltage between the collector and the emitter.


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Sorry about the english, I'm from Portugal

 

Your amp needs a resistor to bias it into class A operation. Our Ebook talks about the subject - http://www.allaboutcircuits.com/vol_3/chpt_4/9.html

 

What value are you using for Vbb? I see the connection and it gives the illusion that the Rb is connected to ground and not the Vbb source.

You can infer the maximum collector current as Vcc / Rc since that is the extremes of the collector current.

 

Thanks for the replies, after all this has to be done in lab by the adjustment of vbb to get the maximum simmetric excursion without distortion.

that link that you showed me, thanks