[en] The dependence of the injection current on the sign of non-compensated electric charge of electret has been studied. Volt-ampere curves of the cathode currents through thin dielectric films of terylene and fluoroplastic have been considered. In ection currents have been observed in redox systems of Ce⁴⁺/Ce³⁺, I⁰/I^-, films serving as cathodes. From the anodic side the solution contained 1M KCl. An effect of the electret state of the film on a limiting injection current has been observed, when adsorption is accompanied by a charge transfer of one of the reagents