Boucherot cell

A Boucherot cell (or Zobel network) is an electronic filter, used in audio amplifiers to damp high-frequency oscillations that might occur in the absence of loads at high frequencies.

The speaker coil inductance of a loudspeaker generates a rising impedance, which is worsened by the output inductor generally found in analog power amplifiers; the cell is used to limit this impedance.

[2] The documentation for some power operation amplifiers suggests the use of a "Boucherot cell between outputs and ground or across the load".

[3] Additionally, Boucherot cells are sometimes used across the bass driver (and mid-range) of a speaker system, in order to maintain a more constant driving point impedance as "seen" by a passive crossover.

[2] Some loudspeaker crossover designs aim to stabilize impedance at high frequencies by including Zobel networks.