Boucherot cell
Image:Zobel Zobel loudspeaker impedance correction.svg|thumb|right|300px|Boucherot cell correcting loudspeaker impedance
A Boucherot cell is an electronic filter, used in audio amplifiers to damp high-frequency oscillations that might occur in the absence of loads at high frequencies. Named after Paul Boucherot a Boucherot cell typically consists of a resistor and capacitor in series, usually placed across a load for stability.
It is commonly seen in analog power amplifiers at the output of the driver stage, just before the output inductor. 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.
The documentation for some power operation amplifiers suggests the use of a "Boucherot cell between outputs and ground or across the load".
Additionally, Boucherot cells are sometimes used across the bass driver of a speaker system, in order to maintain a more constant driving point impedance as "seen" by a passive crossover. In this specific arrangement, the Boucherot cell is part of a Zobel network.
Some loudspeaker crossover designs aim to stabilize impedance at high frequencies by including Zobel networks.