Abstract
This is the supplementary note for the paper "On the characteristics of the arc of Tungar Rectifier" published before by the same author.
Oscillographic studies of the oscillating currents produced by means of a tungar rectifier are performed, namely on a direct current arc and a rectifying arc.
This report treats of the relation between the oscillation and the heating condition of the filament, which forms the cathode of the arc.
When the filament current is of comparatively small value, being less than several amperes, oscillating currents of relatively high audio-frequency are produced traversing the condenser connected across the terminals of the tungar bulb. This oscillation may be considered to be due to an ionic oscillation of negative ions in the arc, as was stated in the previous paper.
When, however, the filament current is increased up to more than fourteen amperes, an intermittent current is suddenly produced in the condenser circuit, which is of low frequency at several hundred cycles per second and is of effective value as high as one ampere.
The reason that such an intermittent current is produced may be explained from the dynamic characteristic curve of the oscillating arc, which can be constructed from the wave form of the intermittent current in, the condenser circuit.
In order to oscillographically observe the oscillations produced by the rectifying arc, the well-known Hull's circuital arrangement for the rectification with kenotron is used.
Considering the relation between the currents flowing in differents parts of the circuits, we can distinctly observe that an oscillating current of audio-frequency is superposed on the current flowing through the rectifier, and that the more the filament current is increased, the less is the frequency of the oscillation reduced, exactly as was the case for a direct current arc.
