Band Stop / Notch Filter Calculator

Band-stop and notch filters are essentially the same - they both attenuate a specific range of frequencies. The term 'notch' is often used when referring to a very narrow rejection band, while 'band-stop' is more general.

The Q factor determines the sharpness of the notch. Higher Q values create narrower rejection bands but may be more sensitive to component tolerances. For general applications, Q values between 5-20 work well.

RC filters use resistors and capacitors and are simpler but have limited performance. RLC filters include inductors and can achieve sharper cutoffs and better performance but are more complex and expensive.

The circuit impedance determines the absolute values of your components. Higher impedance circuits use larger resistor values and smaller capacitor values. Match your filter impedance to your source and load impedances.

Twin-T filters are popular because they can be built with resistors and capacitors only (no inductors needed), making them cost-effective and suitable for audio and low-frequency applications.

The calculated values are theoretical and assume ideal components. In practice, use the nearest standard component values and consider component tolerances, which may affect the exact center frequency and Q factor.

Yes, you can cascade multiple notch filters to reject multiple frequencies or to increase attenuation. However, each stage may interact with others, so proper buffering between stages is recommended.

RC filters work well from audio frequencies up to several MHz. RLC filters can work at higher frequencies but become impractical at very high frequencies due to parasitic effects in inductors and capacitors.