| 摘要 |
639,794. Thermionic valves. PHILIPS LAMPS, Ltd. Aug. 1, 1947, No. 20927. Convention date, Aug. 6, 1946. [Class 39 (i)] In a valve as disclosed in Specification 611,381, comprising a shielding plate 2 and a trimming condenser, one electrode of which is constituted by a part of the shielding plate, and is separated from the semi-circular plate 4 which is secured to a contact pin 3 and forms the other electrode, by a dielectric in the form of an insulating plate 5 which is rotatable about the contact pin 3 and has an aperture 6 which varies the capacity of the condenser when rotation is effected through the slot 7, said shielding plate 2 is provided with incisions 8 and 9 so that the portion which functions as an electrode of the trimming condenser is resilient and engages the insulating plate 5 with a definite pressure, thus preventing movement of the latter during transport or due to thermal strains in the shielding plate 2. The latter is embossed at several points, thus forming elevations 10 which bear against the bottom of the valve and prevent the shielding plate from being slightly pressed in when the valve is inserted in a holder, with consequent possibility of movement of the insulating plate 5. |
