Micro machined transducers have been the focus of study for many groups over the past two decades and as such, a body of literature is dedicated to summarizing the field [57]. As the field has matured, a smaller group of micro transducers has been optimized to provide mechanical work into a micro system. Most notable to the authors are electrostatic, piezoelectric, electromagnetic, shape memory alloy, and thermal micro transducers. This introduction takes a brief look at these technologies and provides some metrics for evaluating a micro transducer technology, given some established requirements. The authors often find that for an application where the transducer is limited in size, powered electrically at limited voltage levels, confined to a limited micro fabrication process, and has relatively large desired mechanical output, the micro actuation technology of choice is electrothermal. These transducers convert electrical energy to mechanical work through localized Joule heating and thermal expansion. [ABSTRACT FROM AUTHOR]