Abstract: An electronic device for regulating and controlling the delivery of yarn (18) coming from feed units of textile machines, which is designed to vary the r.p.m. of a d.c. brushless motor (23) so as to keep it as synchrronized as possible, according to an adjustable scale factor, with the speed of the textile machine served; the device comprises the d.c. brushless motor (23) and an electronic circuit based upon operation of a microcontroller (21) that is able to control the r.p.m. of the motor (23) and the currents (I1, I2, I3) in the phases of the aforesaid motor (23).