Abstract: A fluorescent lampholder fitting has a preheat type circular fluorescent lamp with its ends in proximity and having a first end provided with a starting filament with a first and second filament terminal wire, and a second end provided with a second starting filament with a first and second filament terminal wire. A male screw base electrical connector extends axially along the lamp circle centerline from a housing which supports the lamp in a plane normal to the axis of the screw base. The screw base is provided with three electrical input connections which are adapted to be used in a three-way lampholder of a portable lamp or light fixture. A lamp starter is connected between the first lamp filament and the second lamp filament.

Abstract: A combination lamp comprises a miniature arc tube, a standby filament and a thermal switch in a sealed vitreous envelope. The switch is connected in series with the filament, and the arc tube and the filament have separate inleads for external connections. The switch is closed at room temperature, allowing the filament to light up immediately at a cold start and providing an instant-on feature. During normal operation, heat and light radiated by the arc tube cause the switch to open and turn off the filament. The small size of the arc tube favors a heat balance which allows the thermal switch to cool and reclose quickly in the event of a current interruption, thereby assuring lighting after an acceptably brief delay in the event of a hot restart.

Abstract: A starter circuit for a hot cathode discharge lamp which has a switching element which is connected across the lamp to permit a cathode heating current to flow and then opens to permit the lamp to strike. The starter circuit has a thyristor as the switch element, and a control circuit for rendering the thyristor conductive at a desired point during each cycle of the applied voltage. The control circuit includes means for increasing the instantaneous applied voltage which is required to trigger the thyristor with successive cycles of the applied voltage after switch-on of the circuit. This means preferably includes a capacitor which is progressively charged to provide an increasing bias which must be overcome by the applied voltage. If the lamp fails to strike, the required voltage for triggering goes on increasing until it is too high for the thyristor to trigger at all. No damage can then occur to the starter circuit or the lamp ballast.

Abstract: Protection against potentially destructive arcs which may occur within a gas-filled incandescent lamp when the energized filament fails is achieved by partly embedding separate inner and outer lead-in conductors in an hermetic seal that is formed on one end of the lamp envelope and electrically connecting the conductors by a short uncoiled fuse element that is located entirely within the confines of the envelope. In the case of a halogen-cycle type lamp having a press-sealed envelope, the fuse element comprises a tungsten wire which is preferably from about 1% to 10% larger in diameter than the filament wire and is fastened to the inner lead-in conductor at a point located inside the envelope, and to the outer lead-in conductor at a point which is located within the press seal. Reliable arc-suppression is thus achieved in a practical inexpensive manner with rugged components that are readily made integral parts of the finished lamp.

Abstract: An integral self-contained fluorescent lamp unit comprising an elongated lamp and an elongated ballast resistor adjacent to and alongside the lamp. Metal strip heat radiators are positioned adjacent to and alongside the ballast resistor for dissipating its heat when operating.

Abstract: An improved thermal switch permitting large temperature excursions beyond the design closure temperature without stressing the switch material beyond its elastic limits. It combines a bimetal portion with a spring portion through which movement is transmitted, the former providing sufficient deformation for closure at design temperature, and the latter accommodating excess deformation beyond closure caused by high temperature. It is particularly useful in metal halide lamps having gas filled outer envelopes and requiring shorting of an auxiliary starting electrode to the adjacent main electrode during operation.

Abstract: A circuit for the repetitively pulsed operation of a xenon arc discharge lamp. A first SCR is responsive to a first control circuit when fired to allow the charging of a capacitor through a first inductor from a DC energy source. A second SCR is responsive to a second control circuit, and when fired connects the capacitor through a second inductor to a lamp to provide an operating current pulse for the lamp. Also, upon firing of the second SCR, the capacitor supplies a voltage pulse to a pulse transformer which in turn generates a high voltage pulse for ionizing the lamp. The first SCR is responsive to its control circuit to be conductive only when the capacitor is discharged and the second SCR is responsive to its respective control circuit to be conductive only when the capacitor is fully charged. In actual operation, one SCR must have been non-conducting for a predetermined time before the other SCR is allowed to become conductive thereby to prevent shoot-through.