The Transient Plane Source-Effusivity (TPS-EFF) is a portable meter that uses a 30 mm diameter single-sided TPS sensor with test times of 2 and 10 seconds to ensure one-dimensional heat flow. During the measurement, the sensor is heated using a constant current source while the temperature rise of the sample is simultaneously recorded with time by monitoring the change in electrical resistance of the wire spiral. The slope of temperature against a special function of time is used to calculate the material’s thermal effusivity.