Work out bandwidth of a filter instantly with clear inputs, formula shown and shareable results.
Bandwidth of a resonant filter is centre frequency divided by Q, and the two -3 dB points sit geometrically either side of f0. Rolloff outside the passband is about 6 dB per octave per order, so a higher-order filter rejects out-of-band signals far more steeply.
Filter bandwidth
BW = f0 / Q; the cutoffs are geometrically centred on f0; rolloff = 6 dB/octave per order
Electrical results are planning estimates only. Verify against the applicable wiring rules (IEC 60364, BS 7671, NEC or local code) and have all installation work designed and checked by a qualified electrician.
Geometrically, not arithmetically: f0 is the geometric mean of the two cutoffs, so on a log frequency axis they look symmetric.
Narrow bandwidth means longer settling time and greater sensitivity to component drift, so Q above a few hundred needs crystals or resonators.