Lowpass Filter Calculator

Filter Parameters
Results
Cutoff Frequency (fc)

0 Hz

\( f_c = \frac{1}{2 \pi RC} \) for RC filters

Filter Gain (Av)

0

\( A_v = 1 + \frac{R_f}{R_{in}} \) for active filters

The cutoff frequency is where the signal is attenuated by 3dB (-3dB point).

Bandpass Filter Calculator

Filter Parameters
Results
Center Frequency (f0)

0 Hz

\( f_0 = \frac{1}{2 \pi \sqrt{LC}} \)

Bandwidth (BW)

0 Hz

\( BW = \frac{f_0}{Q} \)

Quality Factor (Q)

0

\( Q = \frac{f_0}{BW} \)

The center frequency is where the filter has maximum gain, and bandwidth is the range between -3dB points.

Circuit Diagram

Circuit Options
RC Lowpass Filter
Key Formulas:

\( f_c = \frac{1}{2 \pi RC} \)

Frequency Response

Graph Options
Key Points
  • Cutoff Frequency (-3dB point) 0 Hz
  • Center Frequency (Bandpass) 0 Hz
  • Bandwidth 0 Hz

Interactive Guide

Filter Types
Lowpass Filters Bandpass Filters Applications Design Tips
Quick Reference

RC Lowpass:

\( f_c = \frac{1}{2 \pi RC} \)

RL Lowpass:

\( f_c = \frac{R}{2 \pi L} \)

Center Frequency:

\( f_0 = \frac{1}{2 \pi \sqrt{LC}} \)

Bandwidth:

\( BW = \frac{f_0}{Q} \)

Quality Factor:

\( Q = \frac{f_0}{BW} \)

Lowpass Filters

A lowpass filter allows signals with a frequency lower than a certain cutoff frequency to pass through and attenuates signals with frequencies higher than the cutoff frequency.

Types of Lowpass Filters:
  • RC Lowpass Filter: Uses a resistor and capacitor in series.
  • RL Lowpass Filter: Uses a resistor and inductor in series.
  • Active Lowpass Filter: Uses an operational amplifier to provide gain and better performance.
Applications:
  • Audio systems to remove high-frequency noise
  • Anti-aliasing filters in analog-to-digital conversion
  • Power supply ripple filtering
  • Signal conditioning in sensor circuits
When designing filters, consider component tolerances as they can significantly affect the actual cutoff frequency.