| 摘要 |
The present invention relates to an arrangement comprising a triac 3 with toothed circuits 9 for controlling the current through an AC current-powered load, preferably a projection lamp 4. The arrangement comprises a comparator 7, one input of which is connected to a grid-synchronous saw tooth generator 6 and the other input of which is connected to an open circuit reference voltage source 8, which has such voltage that the potential of the second input of the comparator 7 without any load other than the comparator 7 itself lies between but close to one of the extreme values of the saw tooth voltage. The reference voltage source 8 has a relatively large internal resistance, so that the potential at the second input of the comparator 7 can be adjusted by means of an external load to at least essentially the other extreme value of the saw tooth voltage. <IMAGE> |
