Hi,

I'm just looking to verify something

From a mathematical point of view:

Gain = -gm*Rc

gm = Ic1/Vt
Rc = 8k

When Vo = +15

AV = -((15/8*10^3)/25*10-3) * 8*10^3
= -600


When Vo = -10

AV = ((10/8*10^3)/25*10-3) * 8*10^3
= 400



Is this correct?


note to mods:

I posted this thread here: http://forum.allaboutcircuits.com/showthread.php?t=63201 however I think it belongs in Homework help.
If you could delete/merge the other one that would be great.

 

Your answer is wrong.

The voltage gain is equal to:

\(AV = Rc * \frac{ gm}{ gm * Re||R3 + 1 }\approx \frac{Rc}{Re||R3}\)

 

Note also that Vout swings up and down because Ic varies, not Rc. Correcting for this will lead to a completely different answer to your present one.