Abstract
An 85 W high pressure sodium discharge lamp ballast for indoor 100 V a. c. source is described. The ballast is composed of a series choke coil with two coils and a switching circuit connected to a junction of the coils. choke coil impedance, turn-ratio between the two coils, blocking voltage of the switching circuit and cut-off current are examined for a suitable operation of the ballast. The ballast consumes 14% less energy and is 50% lighter, than conventional ballast.
