| 摘要 |
484,633. Two-part couplings. GENERAL ELECTRIC CO., Ltd. (Patent-Treuhand-Ges. fur Elektrische Gl³hlampen) May 10, 1937, No. 13285. Drawings to Specification. [Class 38 (i)] [Also in Groups XI and XXXV] A protective device is enclosed within an adapter for an electric incandescent lamp of the type which, when in operation, is filled with mercury vapour at a pressure preferably greater than one atmosphere, to prevent evaporation of the filament or the formation of a discharge between its ends. The device comprises a protective resistor of negligible or positive temperature-resistance coefficient in series with the filament, and a shunting resistor of large negative coefficient connected across the protective resistor. The shunting resistor is heated up by the shunt current through it, until its resistance becomes so low that it shortcircuits the protective resistor. |
