The Wien bridge is a particular type of the Wheatstone bridge of which
two of the four arms are composed of a capacitor as well as a resistor
in parallel and series:
For this bridge to balance, the ratios of the left and right branches
should be the same:
(50)
For this equation to hold, the right-hand side needs to be real, i.e.,
(51)
and the equation above becomes
(52)
In particular, if
and
, we have:
(53)
and
(54)
Wien-Robinson Filter
-
(55)
-
(56)
where
, i.e.,
(57)
-
(58)
(59)
or
(60)
Substituting this into (2) we get
(61)
Substituting this into (1) we get
(62)
We rearrange to get
(63)
(64)
(65)
(66)
This is a band-stop filter with passband gain
,
stop-band
and
.
Further reading for