
Now, let us analyse the process that takes place in the system when the output was
momentarily disturbed by some kind of electromagnetic pickup from some neighbouring cir-
cuit. Assume that the output voltage increased from zero level. This increase is felt at the
inverting input of Opamp through the R
1
R
2
chain. The current drawn by the inverting the
input of Opamp loads this potential divider. However, the Opamp has a very large input
resistance, and hence, the R
1
R
2
potential divider may be considered unloaded. Therefore,
the potential that appears at the inverting input is
β
v
o
, where
β
is the feedback factor and is
equal to R
1
/(R
1
R
2
). Therefore, ...