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Up: Chapter 6: Active Filter
Previous: The TwinT notch (bandstop)
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:
For this equation to hold, the righthand side needs to be real, i.e.,
and the equation above becomes
In particular, if and , we have:
and
WienRobinson Filter


where , i.e.,

or
Substituting this into (2) we get
Substituting this into (1) we get
We rearrange to get
This is a bandstop filter with passband gain
,
stopband
and
.
Further reading for
Next: Butterworth filters
Up: Chapter 6: Active Filter
Previous: The TwinT notch (bandstop)
Ruye Wang
20181211