The Olsen cycle is a pyroelectric cycle, which was developed between 1978 and 1986 by Olsen and Bruno, by Olsen and Brown, Olsen and Evans, as well as by Olsen et al. It has been called the Ericsson cycle. However, the Olsen cycle avoids the least confusion with its analogous process of the Ericsson cycle. The Olsen cycle can generate electricity directly from heat when applied to a pyroelectric material, and has been the most favorable method for the generation of electricity from heat using pyroelectric energy harvesting. It consists of two isothermal and two isoelectric field processes in the displacement versus electric field diagram.