The Measurement of Internal Electro-static Capacities of Triode Vacuum Tubes

Abstract

This is the report of measurements of the internal electroslatic capacities of some homemade & foreign-made triode vacuum tubes. The method of determ ning of these very small capaities of a few μ.μ.F. consists in measuring the charging current by means of ana.c. current meter.(2)
Since no appreciable change of internal capacity is observed between the hot state andthe cold state of the filament, the measurement is carried out at the latter condition.
The results are tabulated in the present report, showing C₁C₂ and C₃, whigh representsthe internal capacity between the grid and the filament, the grid and the plate, the plateand the filament respectively.
These values are greatly different with various kinds of valves, and reviewing theresults, it may le raid that they depends greatly upon the design at the leading and thesapporting wires of electrodes in the bulbs. (Sendni, nov. 1925)