Abstract: A multiple fluorescent lamp ballast circuit of the rapid start type in which heating current is supplied to the lamp cathodes. A time delay switch is connected in series with a starting capacitor across one or more of the lamps, to delay lamp starting until the cathodes are sufficiently heated.

Abstract: An output configuration for an electronic ballast system includes means for effecting independent selection of both pre- and post-ignition lamp filament voltages. The primary of a filament voltage control transformer is coupled to lamp filaments so as to induce a voltage in the transformer secondary windings in relation to the lamp filament current. The secondary windings are arranged so that the voltage induced therein adds to the voltage provided to the lamp filaments by filament drive windings on the ballast output transformer.

Abstract: Energy-saving circuitry for a rapid-start fluorescent lighting system includes a reactance-modifying capacitor coupled in series with first and second fluorescent lamps and includes a filament switch which is operative to conduct filament heating current during starting of the first lamp. The filament switch is coupled between filaments at opposite ends of the first fluorescent lamp and triggers to a low impedance state in response to the lamp starting voltage. A capacitor bypass switch can be coupled in parallel with the reactance-modifying capacitor to reduce the impedance of the series circuit during lamp starting.

Abstract: A safe "phantom" lamp structure for replacing a fluorescent lamp in a two-lamp series circuit connected fluorescent fixture which permits the remaining lamp of the two-lamp fixture to operate. The structure includes, in different embodiments, one or more magnetically or thermally actuated switches which must be closed for completion of the phantom lamp circuit and the switches are closed only after connection of both ends of the phantom lamp to the appropriate fixture sockets.

Abstract: An improved arrangement for providing cathode heating current in a visual display wherein pulses of heating current are sequentially applied at brief intervals, the magnitude of the current and the intervals being coordinated with the cathode thermal inertia so as to maintain cathode temperature within an operative range during the off periods, and wherein potentials for activating the display are applied during such off periods.

Abstract: An illumination control system for gas discharge lamps which can be dimmed is provided in which a central inverter produces sinusoidal output voltage at about 23 kHz. The amplitude of the inverter output is adjustable to dim the lamps. A transmission line consisting of spaced wires having respective thick insulation sheaths distributes the high frequency power to remotely located assemblies of ballasts and lamps. A high power factor rectifier network is disclosed for providing a d-c input to the inverter from the 50/60 Hz mains. Several ballasts are disclosed, which consist principally of circuits using passive linear components. Some of the ballasts disclosed are conjugate ballasts which are those made of complex conjugate impedances which resonate with or near the input power frequency. Some ballasts disclosed are non-linear when the lamp is out in order to limit the open circuit voltage. The ballasts disclosed all have the following characteristics:(a) good power factor (above 0.

Abstract: An illumination control system for gas discharge lamps which can be dimmed is provided in which a central inverter produces an output voltage at a high frequency which can be about 23 kHz. The amplitude of the inverter output is adjustable to dim the lamps. A transmission line consisting of spaced wires having respective thick insulation sheaths distributes the high frequency power to remotely located assemblies of ballasts and lamps. The ballasts consist of passive linear components. A high power factor rectifier network is disclosed for providing a d-c input to the inverter from the 50/60 Hz mains.

Abstract: Electrical lamp ballast system for starting and operating fluorescent lamps with improved efficiency and safety. System includes high leakage reactance autotransformer having primary and secondary windings, and a ballast capacitor connected in series with the secondary winding and two serially connected fluorescent lamps of low starting and operating voltage, the secondary circuit being connected to a tap on the primary winding for reducing the ratio of the ballast power input to the lamp light output. A starting capacitor connected across one of the lamps has a resistor of predetermined resistance connected in shunt therewith to reduce the peak voltage to ground resulting from removal of that lamp from the circuit, so that electrical shock hazard to service personnel is minimized.

Abstract: High efficiency push-pull inverters minimize undesirable energy losses usually resulting from simultaneous conduction and imperfect switching of the transistor switching means. In each of the disclosed circuits, a saturable inductor and a diode are connected in parallel and across the base-emitter junction of each transistor. Voltage on the base of each transistor causes its associated saturable inductor to saturate, and the saturated inductor then terminates the flow of base current and provides a path for rapid evacuation of the charge carriers stored in the transistor base-emitter junction in order to render the transistor rapidly non-conductive. Each diode provides a drain path for current continuing to flow through its associated saturable inductor after junction evacuation. A novel triggering means initiates oscillation of the inverters.

Abstract: The present discharge lamp system comprises two or more serially connected discharge lamps connected across a pair of power input supply terminals through a ballast circuit and two or more serially connected semiconductor starter circuits. The starters are connected in parallel with their respective discharge lamps and have inherent breakdown voltages, whereby the total value of the breakdown voltages for each starter is higher than the source voltage at the power supply terminals. The system further comprises voltage dividing circuit elements enabling the conduction of one of the starters before the conduction of the other starter or starters in response to the source voltage, whereby the starters operate sequentially. At least one of the starters employs a backswing booster including a series circuit of a nonlinear inductor and a switching semiconductor and a capacitor connected in parallel with the series circuit to provide a sufficient starting voltage for the associated discharge lamp.

Abstract: A device which is designed to save electrical energy expended by a regular rapid start fluorescent lighting fixture having a plurality of lamps, or tubes, and a conventional ballast. The device comprises the combination of a step-up transformer, a resistor and two capacitors, all of which are mounted externally of the ballast. The device is wired in series with the ballast and one of the lamps to allow normal ballast voltages to be delivered to the lamp circuit, thereby eliminating any detrimental effects to the lamps or ballast. At the same time, the current to the lamps and consequent consumption of power by the lamps is substantially reduced to save electrical energy while providing a reduced, but uniform level of illumination.

Abstract: There is provided in combination with a rapid-start series-sequence type ballast for two low-pressure mercury discharge lamps, apparatus for reducing the power consumption of both lamps. The apparatus utilizes switch means in conjunction with a capacitor to limit the current supply to the lamps after the lamps are energized. The switch means has two members in series circuit arrangement with one of the electrodes of one of the lamps. Each member is connected on opposite sides of the electrode. The capacitor is connected in parallel circuit arrangement with one of the members. Initially upon energization the switch means has a low impedance state to permit current flow and then switches to a high impedance state. The switch means permits preheating of the electrode and thereafter upon response to current flow switches and causes the lamp current to pass through the capacitor and thereby decrease by a predetermined amount the current through the normally operating lamps.

Abstract: A sinusoidal wave oscillator ballast circuit includes a tuned oscillator coupled to a DC rectifier means coupled by a power factor correction circuit to an AC potential source. The oscillator is coupled to an inductor means including a first and second transformer means with the secondary winding of the first transformer means coupled to the oscillator, the primary of the first transformer means in series connection with a capacitor and the primary winding of the second transformer means to form a resonant circuit, a first secondary winding of the second transformer means coupled to a lamp circuit to form a load circuit shunting the capacitor of the resonant circuit and a second secondary winding of the second transformer means having opposite ends connected by clamping diodes to the DC rectifier means. Means for compensating for "storage time" of the transistor of the oscillator and for conditioning the line to transients and radio frequency interference (RFI) are also provided.

Abstract: A high frequency power supply with inductive coupling and a SCR starter to light two fluorescent lamps is described. It supplies high frequency square waves to the fluorescent lamp for improved light output, efficiency and stability of operation. The rectified line voltage from a full wave rectifier is fed via a SCR starter to two transistors that form an inverter circuit. The inverter circuit is coupled to a ferrite core autotransformer. The secondary windings of the autotransformer are used to heat the filaments of the electrodes of the fluorescent lamp, and to form a reactive coupling along with inductors for stabilizing the arc discharge of the fluorescent lamp.

Abstract: A ballast for a rapid start fluorescent lamp with heated filaments has a secondary winding supplying lamp current, tertiary windings for supplying heater current to the filaments, and solid state switching circuits in secondary circuits through the filaments. Each switching circuit, which may be integrated with the ballast circuit or connected to a filament within the lamp envelope, comprises two voltage divider resistors having a common junction coupled to the gate of a triac whose primary electrodes are connected in parallel with the voltage divider. The triac is in series with the filament and supplies heating current to the filaments prior to lamp starting. When the lamp starts and conducts rated operating current the voltage divider reduces the voltage at its junction and at the triac gate below triac breakdown level thereby substantially eliminating heater current.

Abstract: A circuit employing an oscillator having a feedback loop for supplying operating current at a frequency in the range 20-25 kilohertz to a pair of fluorescent lamps connected in series. The heater filament of the first lamp is made a series element in the feedback loop of the oscillator, so that removal of that lamp disables the oscillator. Switching means is provided to bypass the open socket terminals of the second lamp when it is removed from its sockets, permitting power to continue to be supplied to the first lamp.

Abstract: A fluorescent lamp installation for very high intensity illumination uses standard rapid start filament type lamps with standard ballast remote from the lamp pairs to reduce cooling requirements. The heavy wiring harnesses previously required of six leads between each ballast and a lamp pair are reduced to one with a common lead for all the lamp pairs.

Abstract: An attachment is provided for inclusion in a two-lamp rapid-start type fluorescent lamp and encapsulated ballast transformer combination to reduce the electrical power consumption thereof, comprising an isolation transformer and a capacitor. The isolation transformer is connected in circuit between the secondary heater winding at the electrical leads that extend from the encapsulated ballast and the first heater terminals of the first lamp, and the capacitor is connected in circuit between the primary and secondary of the isolation transformer.

Abstract: There is provided in combination with a rapid-start series-sequence type ballast for two low-pressure mercury discharge lamps, apparatus for reducing the power consumption of both lamps. The apparatus utilizes switch means in conjunction with a capacitor to limit the current supply to the lamps after the lamps are energized. The switch means has two members in series circuit arrangement with one of the electrodes of one of the lamps. Each member is connected on opposite sides of the electrode. The capacitor is connected in parallel circuit arrangement with one of the members. Initially upon energization the switch means has a low impedance state to permit current flow and then switches to a high impedance state. The switch means permits preheating of the electrode and thereafter upon response to current flow switches and causes the lamp current to pass through the capacitor and thereby decrease by a predetermined amount the current through the normally operating lamps.

Abstract: High efficiency push-pull inverters minimize undesirable energy losses usually resulting from simultaneous conduction and imperfect switching of the transistor switching means. In each of the disclosed circuits, a saturable inductor and a diode are connected in parallel and across the base-emitter junction of each transistor. Voltage on the base of each transistor causes its associated saturable inductor to saturate, and the saturated inductor then terminates the flow of base current and provides a path for rapid evacuation of the charge carriers stored in the transistor base-emitter junction in order to render the transistor rapidly non-conductive. Each diode provides a drain path for current continuing to flow through its associated saturable inductor after junction evacuation. A novel triggering means initiates oscillation of the inverters.