OXIDE CATHODE AND PRIMARY GRID EMISSION STUDIES.
Monthly rept. no. 10 for Feb 48,
WESTINGHOUSE ELECTRIC CORP BLOOMFIELD NJ LAMP DIV
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Efforts have been continued towards the determination of the cause of electrical breakdown in the 715 type tube by developing the technique of photographing oscilloscope traces of control grid current vs cathode current. Appreciable variations in control grid current and voltage were traced to 120 cycle ripple in the keyer supply voltage and eliminated by addition of filter condensers. The 715B tested displayed a very definite type of reproducible arcing apparently between the end of the cathode sleeve and the support insulator. The special tube for x-ray analysis of the material evaporated from an oxide cathode has been reassembled with a platinum anode and exhausted. Further measurements have been made on the thermionic emission from carbonized Grade A nickel contaminated by evaporation from an oxide cathode. Author