Abstract
In high frequency (HF) operation of a fluorescent lamp (FL) with an aid of ripples caused by full wave rectifier circuit without filter capacitor, the luminous efficacy would be reduced in considerable order because of the dark angle to HF lamp current.
To improve the efficacy, it is proposed to use a switching element and smoothing condenser in the redtifier circuit.
Using this circuit, high efficacy and high power factor for the HF operation of the FL can be achieved.
This switching element is composed of a semiconductor diode, a thyrister and a trigger unit for driving the thyrister.
In the rectifier circuit, with a smoothing condenser of 15 μF, 3, 330 lm of luminous flux is obtained, which exceeds 10% in luminous efficacy compared with the ordinaly AC operation and, also, a power factor more than 85% can be achieved.
