On Thu, 1 Jun 2006 17:55:47 +0100, M.Joshi
put finger to keyboard and composed:


Just to clarify a few points:

I have come across a capacitor on the input which is to block DC; and
also in the feedback loop which gives an Integrator function I believe
however, in this circuit, there was a resistor in the feedback loop and
another resistor and capacitor in series to ground from the inverting
input?

Thinking about it now, could it form some sort of filter (Low pass)?

Is this it?

+---- Rfb -+
| |\ |
C | | \ |
|---||-- Rin -+-|- \ |
_|_ | \____|__ Vout
= | /
Vin ---|+ /
| /
|/

Av = Vout / Vin
= 1 + Zfb / Zin
= 1 + Rfb / (Rin + 1/jwC)

At DC, C=0 and Av = 1.
At high frequencies, Av = 1 + Rfb / Rin

At high frequencies the circuit behaves like a normal non-inverting
amp, while at low frequencies the gain approaches unity.

- Franc Zabkar
--
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