This module provides students an introduction to physiological measurement using biosensors and transducers. This module deals primarily with gaining an understanding of the physical principles that govern the measurement of a biological variable or system using a transducer, which converts the variable into an electrical signal. By the end of the module, students will understand various measurement devices and approaches including the underlying biological process that generates the quantity to be measured or controlled. The basic biosensors and transducers used to measure pressure, fl ow, volume, and kinematics are examined, along with various aspects of electrical and imaging instrumentation. Current and future applications of biosensors and biomedical devices are also explored.