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Radio Record, Volume II, Issue 6, 24 August 1928, Page 32

HE life of a radio valve is governed by the filament, which is the wire that is heated to red heat by the curreut from the A battery, or, in the case of alternating current:type tubes, by the low voltage current from the filament heating transformer. The fila ‘ment is couted with a substance which when heated produces a copious flow of electrons that travel from the filament through the grid to the plate. Excessive filament current will, of course, burn out the filament and abruptly terminate the usefulness of the tube; but if ihe tube is normally used, its useful life will be governed by the flow of the electrons from the filament. After somewhat over a thousand hours of use, the electron flow from the filament will gradually cease, and when it has fallen below a certain critical point the life of the valve is ended, and it should be replaced with a new valve. The fact that the filament still glows when the A battery current is turned on means nothing except that the filament is not burned out. BUS line operating between Birmingham and. Montgomery, Ala., U.S.A., has recently equipped all of its -yehicles with receiving sets that are proving popular with passengers. They give the travellers news of.the day, the latest weather reports, and seasonal sports. iF {RENCH radio manufacturers are christening their sets with tonguetivisting, jaw-breaking names. The Elgedyne, the Strobodyne, Zutterodyne, Supermoduladyne, Tubeheteredyne, Strazodyne, and Supertrias are a few of the names. ve,