Abstract: An electronic ballasting circuit provides high efficiency ballasting for most common types of fluorescent lamps. The circuit consists of a half-bridge inverter providing a substantially squarewave voltage across a series-combination of an inductor and a capacitor. The fluorescent lamp is connected in parallel circuit with the capacitor in such a way that the current flowing through the capacitor also flows through the lamp cathodes, thereby providing continuous low voltage heating therefor. The values of inductance and capacitance are so chosen that the series-combination has a natural resonance frequency that is substantially equal to or lower than the lowest frequency component present in the squarewave voltage.

Abstract: A self-oscillating half-bridge inverter is powered from a power-line-operated rectifier means providing a DC voltage with a relatively high ripple content. The inverter is loaded by way of a series-tuned high-Q LC cirucit connected across this DC voltage. A pair of fluorescenet lamps is series-connected across the tank-capacitor of the LC circuit. Also connected across the DC voltage is an arrangement of three energy-storing capacitors charged in series and discharged in parallel; which arrangement results in the current drawn from the power line being of relatively high power factor and low harmonic distortion. Charging current for the energy-storing capacitors is derived from the high frequency current flowing through the LC circuit; and charging occurs only during periods near the peak of the power line voltage.

Abstract: A thin disc-like device for attachment to the base end of an incandescent light bulb to provide an auxiliary voltage reducing circuit interfaced between the central base contacts of the light bulb and its cooperating lampholder for purposes of extending the rated life of the light bulb. The device is made up of a generally annular insulator base, which protectively houses, locates and mounts a laminated contact assembly made up of a pair of registeringly disposed brass or copper foil electrical conductor contact plates separated by an intervening sheet insulator; the conductor plates having interfacial soldered connections with an interposed flat leaderless silicon rectifier chip. A compressible annular mounting gasket is adhesively secured to the upper side of the contact assembly, its base housing and the base of the light bulb.