On the Mechanism of Electron Oscillations in a Triode

Abstract

This paper deals with the different types of electron oscillations which occur in the Barkhausen and Kurz retarding field of a triode having a high positive potential applied to its grid, and zero or small negative potential applied to its anode. Four different frequency ranges were found as follows: (1) In the retarding field between the electrodes there occur electron oscillations whose frequency in general increases with increasing field strength. The wavelengths can be calculated from the potentials and the tube dimensions under the assumption that the electrons vibrate about the grid: Barkhausen-Kurz oscillations. (2) If there is an oscillation system connected to the tube electrodes, alternating fields are superposed on the steady fields produced by the d.c. voltages. As is theoretically shown in a simplified case, these tend to increase the frequency of the electrons and a building up process takes place, the final state of which is the natural frequency of the oscillation system: Gill and Morrell oscillations. Between both types of oscillations there is a constant transition region where the frequency follows neither the natural wave of the oscillation system nor the Barkhausen-Kurz laws. (3) If in Barkhausen-Kurz oscillation the electrons vibrate about the grid (1), oscillations of higher frequency can appear with a grid of close mesh, which no longer occupy the whole anode-cathode space, but are confined to the anode-grid space. The frequency of a hypothetical oscillation in the grid-cathode space can be determined experimentally from the difference of the "longer" and "shorter" waves.