| 摘要 |
PURPOSE: To make possible a double spot system in DC lighting, and the reduction in electric power and the increase in light output by using two systems of a DC lighting circuit, and connecting one circuit to electric power supply through an insulating transformer. CONSTITUTION: A double spot system is provided with two sets of a circuit composed of a capacitor 1-1, a diode bridge 1-2, a smoothing coil 1-3 and a smoothing capacitor 1-4 and a circuit composed of a capacitor 2-1, a diode bridge 2-2, a smoothing coil 2-3 and a smoothing capacitor 2-4. One of the circuits is directly connected to electric power supply 7, and the other is connected to the electric power supply 7 through an insulating transformer 6, and they are formed as independent two electric power supplies by restraining a circulating current. When a switch of the electric power supply 7 is turned on, a starter 4 contacts with it by glow discharge of the starter 4, and an electric current 11 preheats an electrode of a lamp. Next, when contact of the starter 4 separates from it, kick voltage is simultaneously generated in the coils 1-3 and 2-3, and two cathode spots appear in a filament of the lamp. |
