Monolayers of distearoyl phosphatidylcholine spread on the water \ 1,2-dichloroethane interface have been studied in a novel type of Langmuir trough. Isotherms of the lipid have been measured at controlled potential differences across the interface, and cyclic voltammetry has been applied at a controlled surface pressure. Electrocapillary curves derived from the isotherms agree with the ones measured at true thermodynamic equilibrium. At positive potentials the adsorption of the lipid appeared to be weak while at negative potentials rather stable monolayers were obtained.