Properties of a Thermoelectric Cell

A gas-filled diode is proposed as a useful device for the direct conversion of heat energy into electrical energy. A vacuum diode operated with no applied voltage developed an electromotive force between the two electrodes, which was dependent, among other things, on the temperature difference of the electrodes. The hot electrode was electrically positive with respect to the cold collector. When an external load resistor was joined to the electrodes, the characteristic cell currents were of the order of one mu a per cm/sup 2/ of emitting surface for electrode spacing of the order of one cm. The addition of a very small amount of easily ionized gas such as cesium vapor iuto the cell coutainer changed the cell characteristics drastically. The cesium vapor had little effect on the developed emf. The cell impedance was lowered by many orders of magnitude. A rough colorimetric determination indicates an efficiency of about 5% at peak power output. The results of the investigation are shown graphically. (A.C.)