Do 0.1 uf and 100 k ohm act as low-pass filter in here?
Answer
Do 0.1 uf and 100 k ohm act as low-pass filter in here?
No, since there is no current through the parallel RC network, there is zero volts across the network and so
Vout=V−=V+=Vin
thus, the circuit implements a unity gain buffer:
Vout=Vin
Another way to see this is to consider the canonical non-inverting configuration in the frequency domain:
The transfer function (frequency response) is:
VoutVin=1+Z2Z1
In the schematic you provide, $Z_1$ is an open circuit, i.e. $Z_1 = \infty $. Thus, the transfer function for your circuit is:
VoutVin=1+Z2∞=1
which is, as before, just a unity gain buffer. Now, if you place a resistor $R_1$ to ground from the inverting input, the transfer function is:
VoutVin=1+100kΩ||1jω(0.1μF)R1
which will provide some filtering - the details of which I will leave as an exercise for the reader.
:)
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