An electric motor, in particular a motor and gear box unit for activating functional equipment in a vehicle, includes a rotor shaft carrying a commutator co-operating with conductive brushes disposed in brush supports fixed to a printed circuit card ; the motor is provided with means for enabling brush supports to be fixed to the printed circuit card solely by surface mounting. A first electrode having a doping of a first conductivity type laterally abuts a doped semiconductor region having the first conductivity type, which laterally abuts a second electrode having a doping of a second conductivity type, which is the opposite of the first conductivity type. The bottom plate includes a locking portion forming a catch. Then, when a voltage of the pre-discharging pulse exceeds 350 V being a discharge initiating voltage between facing electrodes, since lots of activated particles produced by the surface discharge exist in the discharging space, a feeble discharge between facing electrodes occurs.