Rapid starter switch for a fluorescent lamp

Abstract

An improved starter switch which provides a rapid firing of a fluorescent lamp within 0.8 second has been found. An external appearance and the size of the present starter switch are almost the same as those of a prior glow switch which is slow to fire a fluorescent lamp, therefore, the present starter switch is replaceable to a prior glow switch by merely inserting the present starter switch to a socket of a prior glow switch. The present starter switch has a connector cap which is to be able to be engaged with a socket for a glow switch, a printed circuit board mounting circuit components and connected to said connector cap by lead lines, and a housing fixed to said cap and covering said printed circuit board. The circuit elements mounted on the printed circuit board include at least a non-linear capacitor which has a saturation characteristics between a voltage applied to the capacitor and the charge stored in the same, and a semiconductor switch which conducts upon the application of the voltage higher than a predetermined threshold voltage and holds the conductive status until the current in the same reaches almost zero. Following to the switching OFF of the semiconductor switch when the source current is almost zero but the source voltage is almost maximum due to the presence of an inductive ballast, the non-linear capacitor is charged but is saturated in a short time, then, the charge current of the capacitor is interrupted. The interruption of the charge current of the non-linear capacitor induces the high firing pulse voltage in a ballast inductor which is connected in series with a fluorescent lamp, and said pulse voltage fires a lamp.