A dependent transducer is a device that measures a physical quantity and outputs an electrical signal that is dependent on the value of the measured quantity. This signal can be used for a variety of purposes such as ammeters, voltmeters, or even in medical devices such as EKG machines. There are a variety of synonyms that can be used to describe this type of transducer, including sensor, detector, converter, gauge, sensor system, and transducer system. Regardless of which term is used, the critical aspect of a dependent transducer is that it relies on the quantity being measured to output a signal that can be interpreted and used for other purposes.