a thermionic electric converter is disclosed wherein an externally located heat source causes electrons to be boiled off an electron emissive surface interiorly positioned on one end wall of an evacuated cylindrical chamber . the electrons are electrically focused and accelerated through the interior of an air core induction coil located within a transverse magnetic field , and subsequently are collected on the other end wall of the chamber functioning as a collecting plate . the emf generated in the induction coil by action of the transiting electron stream interacting with the transverse magnetic field is applied to an external circuit to perform work , thereby implementing a direct heat energy to electrical energy conversion .