Piezo/pyroelectric films are capable of generating electrical signals in response to mechanical stress or heat flow, making them the equivalent of a capacitor connected in parallel with a leakage resistor and current source. The piezo- and pyroelectric coefficients, and electrical and thermal time constants of such films can be useful in the design of medical sensors. The author describes three electronic interface circuits: a voltage follower, current-to-voltage converter, and charge-to-voltage converter. Applications for such transducers include a contact microphone, strain-gauge plethysmograph, respiration monitor, thermal imaging sensor, “instant” thermometer, and a thermal scanner.