Abstract: A lighting apparatus which provides high voltage pulses for starting a high pressure sodium lamp. The apparatus includes two capacitors, two blocking diodes, a voltage sensitive symmetrical switch, and multiple resistances across which pulses are distributed. The aforementioned elements are electrically connected together and with a tapped ballast reactor so that one of the capacitors charges through an impedance in the negative half-cycle, and thereafter, when line voltage goes positive, the other capacitor charges through an impedance equal to the sum of the multiple resistances. When the voltage of the capacitors reaches a predetermined voltage exceeding the breakdown voltage of the voltage sensitive symmetrical switch, the capacitors discharge. This discharge, because of an autotransformer relationship within the reactor, produces a high voltage pulse of predetermined height and width once per each cycle of the source voltage.

Abstract: Lighting apparatus provides high-voltage pulses for starting high-pressure sodium discharge lamps and thereafter provides operating ballasting. The apparatus uses a voltage amplification circuit the output of which is applied across a ballast reactor which is connected thereto in autotransformer relationship. This provides a sufficiently high-voltage starting pulse, even when ballast reactors of low open circuit voltage are used, to initiate the operation of high-pressure sodium discharge lamps.