Abstract
Fluorescent lamps offer a wide range of colour and high efficiency but have not been used for theatre lighting due to the lack of means of controlling brightness. The development of circuits for this purpose is traced from the quick start circuit used for general lighting purposes. The importance of heating the filaments to full thermionic emission and the need for a separate impedance for each lamp circuit is stressed. A range of dimming of over 300 to 1 can be obtained with 2ft. 40-watt lamps. It is shown that relative efficiency of the fluorescent lamp compared with the incandescent lamp is considerably increased when coloured effects are required due to the use of additive light mixtures instead of subtractive filters, the ratios of efficiencies being increased from 2 or 3 to 1 to as high as 40 to 1. Reference is also made to the new lighting effects obtainable.
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