| 摘要 |
The light yield, which is relatively low in the case of known arrangements, is to be increased without leading to a significant reduction in the r.m.s. current through the lamp (8). The output terminals of a rectifier bridge (3, 4, 5, 6) are connected to one another, on the one hand, by a series circuit composed of a resistor (7) and a low-pressure sodium-vapour discharge lamp (8) and, on the other hand, by a capacitor (9). The lamp (8) has a U-shaped discharge tube (10) surrounded by an outer bulb (11). The discharge tube (10) contains sodium and 5.5 torrs of neon with an admixture of 1% argon. The inside of the outer bulb (11) is provided with a layer, composed of indium oxide, which reflects infrared radiation. The maximum instantaneous current density through the discharge tube (10) is below the value of S = 165 + 1.3 . (T-245)<2> mA/cm<2>. The r.m.s. current density in the discharge tube (10) is above the value of 0.8 SmA/cm<2>. <IMAGE> |
