Hi,anyone know that how to find closed-loop gain(Vout/Vin) for this op amp?Thanks

 

Since I am too lazy for hand calculation, I have used a symbolic analyzer:

H(s)=N(s)/D(s) with

N(s)= R2*Z(s) + R1*Z(s) + R1*R2 + R*R1)
and
D(s)=R2*Z(s) + R1*Z(s) + R1*R2 + R*R2)

Note: Two resistors assumed to be equal (accorcing to the drawing). R1 and R2 are the pot resistances (left, right) with R1+R2=Rp.

 

Thanks.If I desire to get maximum gain 15db and minimum gain -15db, how can I calculate the values of R,R1,R2 and Rp? Can I set the value of R and Rp by myself?

 

What about Z(s)? Really frequency-dependent?

 

This circuit look like a part of a equalizer circuit. If so try read this
http://feucht.us/writings/graphic_equalizer.pdf
http://www.grix.it/UserFiles/diegobincoletto/Equalizer_OK.pdf