A strong pyroelectric response can be induced in ferroelectric materials, both at and above their transition temperatures, by the application of an electric field. This can be understood in terms of a phenomenological model of transition. Lead scandium tantalate (PST) is a perovskite ferroelectric with a first order transition at 25–30°C. Its electrical properties have been measured against field and temperature, showing a strong induced pyroelectric response (peak value of 0 006Cm-2K-1) and a high peak FD(dielectric loss) figure of merit of 16 × 10-4Pa-½. These give it a particular advantage in applications requiring fine geometries for example large thermal imaging arrays.