| 摘要 |
1. A circuit arrangement for starting and operating a low-pressure discharge lamp from a direct current source, this lamp being provided with two electrodes, of which at least one is preheatable, in which an electronic switching element arranged in parallel with the lamp and in series with the preheatable electrode (cathode) is switched to its non-conducting state after the starting temperature of the preheated electrode has been reached, as a result of which the heating current circuit is interrupted and the full direct voltage is applied to the lamp, characterized in that the direct current source (1 to 3) produces a pulsatory direct current and the electronic switching element (8) is switched by a Schmitt trigger (13) controlled in dependence upon the temperature of the preheated electrode (6), wherein the Schmitt trigger derives from the voltage drop across the preheated electrode a supply voltage via a peak voltage store arranged in parallel with the preheatable electrode and comprising the series arrangement of a diode (14) and of a charging capacitor (15). |
