Costant time

[marcoo_]

Hi, i would like to know what are time constants of this circuit.
I mean the time constants of both capacitor.
I know this is an active band pass filter, but i'm not interested about the center frequency of the filter, i would like to know the formula of both cutoff frequencies.
Thanks (sorry for my english...)
**broken link removed**

 

[Hero999]

Are you talking about the time or frequency domain?

 

[marcoo_]

Hi, i'm interested about the cutoff frequiences introduced by capacitors.

 

[Hero999]

The gain of the amplifier is simply -R3/R1.

C1 and C2 determine the lower and upper cut-off frequencies respectively.
[latex]F_{C_{lower}} = \frac{1}{2\pi R1 C1}[/latex]
[latex]F_{C_{upper}} = \frac{1}{2\pi R1 C2}[/latex]

I don't know what R2 does, it will reduce the gain but not by much as it's at a vitual earth potential, I'd remove it if I were you. If you want add a resistor to limit the effect of the bias currents then it should be the same value as R3 and be inbetween the +input and 0V.