Lighting system for TV studios and theatres - uses rectangular wave which is of same frequency as AC mains to supply discharge lamps

摘要

The lighting system, for television studios and theatres etc., has its gas discharge lamps supplied from a rectangular wave a.c. current. The rectangular waveform is obtained by converting the normal a.c. supply. The supply circuitry consists of a rectifier (2) to rectify the supply, a setting circuit (3) to draw d.c. in pulses from the rectifier, a smoothing circuit (4) to generate a pure d.c. current from the d.c. pulses, a regulating circuit (9, 10) to control the lamp, a static inverter (5) to produce the rectangular wave (same frequency as the a.c. supply), and a sync. circuit (6).