Sallen-Key Low-Pass Filter Calculator
Introduction & Importance
Sallen-Key low-pass filters are essential in audio and signal processing, enabling smooth transitions between frequencies. Our calculator simplifies the design process, ensuring accurate and efficient filtering.
How to Use This Calculator
- Enter the desired cutoff frequency (Hz).
- Enter the sample rate (Hz).
- Enter the quality factor (Q).
- Click “Calculate”.
Formula & Methodology
The Sallen-Key filter is a second-order filter with the transfer function:
H(s) = Vout(s) / Vin(s) = 2 * Q * (s / (s^2 + s * (1/Q) + 1))
Our calculator uses this formula to determine the component values (R1, R2, C1, C2) based on the given parameters.
Real-World Examples
Data & Statistics
| Filter Type | Order | Cutoff Frequency (Hz) | Attenuation (dB) |
|---|---|---|---|
| Sallen-Key | 2 | 1000 | -40 |
| Butterworth | 2 | 1000 | -39.8 |
Expert Tips
- Higher Q values result in sharper cutoff but may cause instability.
- Use a sample rate at least twice the highest frequency of interest (Nyquist-Shannon theorem).
Interactive FAQ
What is the difference between a low-pass and high-pass filter?
A low-pass filter allows frequencies below the cutoff frequency to pass, while a high-pass filter allows frequencies above the cutoff frequency to pass.