Fluorescent lamp ballast that has no transformer is obtained by use of a transistor inverter. The inverter has two small inductors, two capacitors, a power transistor and control circuit. The control circuit drives the power transistor with appropriate duty factor, and high frequency power of 15-25 kHz is generated to operate the lamp. The control circuit has a function that keeps the lamp power or light output at a preset value. Hence, the ballast has a good regulation against the supply voltage fluctuation. The function of the control circuit is also useful for dimming or light controls. The ballasts for 40-80 W lamps with 100 V supply are obtained with light weight and high efficacy.
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References
1.
Hehenkamp, T. and Wilting. J.J., Philips Tech. Rep., 20, 362 (1959).
2.
Davies, 1. F. and Dunthorne, D., Proc. IEE, 107A, 273 (1960 ).
