Electronic motor speed controllers first appeared during the 1980s and many were based on dedicated integrated circuits originally designed as a servo controllers. However, with suitable circuit modifications, these ICs could also be used as the basis for a simple electronic speed controller. Since that time a number of significant events have occurred:- ? The workhorses of many older electronic motor speed controller designs, the tried and tested ZN409 and ZN419 servo amplifier ICs, have been made obsolete. ? MOSFET technology has developed and devices are now available with performance improvements that can be used to good advantage in a speed controller for R/C models. ? The PIC range of microprocessors is readily available and offered at reasonable cost. Because of these changes it seemed the right time to re-examine the possibilities now available with a view to designing a simple low-cost speed controller using a microprocessor to increase the range of features that may be included and advanced MOSFETs to reduce the parts count.