How twin-t notch works
Two T networks operate in parallel. The resistor T uses R1 = R2 and C3 = 2C1. The capacitor T uses C1 = C2 and R3 = R1/2. Companion values follow the two editable controls so the ideal notch stays balanced. An output load or mismatch makes the notch shallower.
Ideal component values and no output load. Real tolerances and loading change the response.
Change the form inputs or click a component value on the schematic. Choose Try in CircuitSim to simulate the configured circuit.