 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".