Abstract: Starting and operating method and apparatus for discharge lamps comprises a current-limiting and rectifying means which provides at its output a low-ripple current-limited direct current. To effect lamp starting, a series-connected inductor and capacitor form a high "Q" resonant circuit with the capacitor connected across the lamp to be operated. This starting circuit connects through a blocking capacitor and charging resistor across the low-ripple source of DC. A pair of transistors which comprise an oscillator are connected emitter-to-collector across the source of DC, with the common-connected emitter and collector connected to the blocking capacitor. A drive air-core transformer has separate feedback windings in the starting and operating circuits and drive windings are associated with the transistors. A trigger diode is used to initially pulse one of the transistors which initially oscillate to generate square waves having a frequency corresponding to the resonant frequency of the starting circuit.

Abstract: Unitary light source comprises compact HID lamp and starting and operating circuit therefor operable from household AC energizing potential. The HID lamp is ballasted by incandescent filament means which also provides the major portion of developed light during HID warm up and after power interruption. The ballast filament and input terminals of a full-wave rectifier connect in series across the light source input terminals and the HID lamp connects across the rectifier output. A low-impedance path means and high-voltage pulse generator, which includes a high-voltage electrode operatively associated with the HID lamp, connect across the rectifier input. Initially, the voltage developed across the rectifier input is relatively high and the pulse generator and low-impedance path means are responsive thereto to devleop high voltage pulses and also provide a low impedance path in series with the ballast filament to cause it to incandesce brightly.

Abstract: A pair of pancake-like coils have a coil axis substantially colinear with one coil mounted to a framework and the other coil mounted on a movable member. The coils are wound such that when electrically energized simultaneously the resulting magnetic fields are in opposition, thereby producing a repelling force therebetween. A spring is disposed between the framework and the movable member to urge the movable member in a sense opposite to the repelling force. A power supply is connected to the coil pair providing for a high initial energy transfer and a lower sustaining energy transfer. A shock absorber is mounted on the framework to arrest the moving member which is set in motion by the repelling force. An armature is attached to the moving member which enters the field of a holding coil as the moving member is displaced by the repelling force. When the holding coil is energized with the armature situated therein, the moving member is held against the spring force.