A surface micromachined micro magnetic actuator(a1so called a magnetic flap) as an integrated part of an active a microelectronics compatible process also makes it an reasonable choice for MEMS. micro electro-mechanical fluid control system is described here. The flaps are fabricated by surface micromachinin$, technology and are capable of achieving large deflectio/ns(above 100pm) with magnetic forces in stationary aii. Special microfabrication issues involved in fabricatin magnetic flaps with large areas are discussed. Metripsic stresses of thin film materials and frequency respbnse, are presented. Thermal actuation is capable of prbducing large flap displacements and has been theoreticdlly and experimentally studied. ch { nical characterizations of the flaps, including the in-I