[sdiy] Weird Serge Resonant Filter topology in upper bands

René Schmitz synth at schmitzbits.de
Tue Dec 13 10:39:54 CET 2022

On 13.12.2022 10:22, René Schmitz wrote:
> But if you swap + and -, and tap at the -input, then it works like I'd 
> expect.
Now it starts to look familiar. The opamp forms a negative impedance 

And of course one can as well tap at the + input. Forming a voltage 
divider between C2/R1 and the NIC reflected R4/C1 impedance.

synth at schmitzbits.de
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