Abstract: A ballast apparatus for series-sequenced gaseous discharge devices includes at least one pair of series-sequenced discharge devices having series-connected filaments with a first rectifier means coupling a filament of one discharge device to the transformer and a second rectifier means coupling the series-connected filaments to the transformer whereby current flow is inhibited until both discharge devices are secured in the fixtures and dangerous socket-to-ground voltages are prevented during discharge device installation.

Abstract: A thermionic fault current limiter utilizes either a vacuum or plasma environment for a plurality of spaced conduction electrodes. The electrode can be supported by insulative spacers with the electrode providing shadow shields for the supporting spacers. Electrode spacing, power density, temperature gradients, and control grids can be utilized for optimum operation and in establishing self-absorption of energy for a desired operating environment. Cesium desorption from the electrode surfaces can be utilized to enhance current termination.

Abstract: A lamp circuit is provided having a constant current-type AC power source and a plurality of isolation transformers coupled in series with the AC power source. The secondary circuit of each isolation transformer is connected to an electric lamp. The output voltage of the constant current-type AC power source is detected to determine the times when the output voltage crosses the zero voltage level. A disconnected lamp in the circuit results in a distortion of the output voltage waveform due to the magnetic-saturation characteristics of the isolation transformer coupled to the disconnected lamp. The output voltage waveform is integrated over time between the time periods when the output voltage signal crosses the zero axis. The result of the integration is compared with a reference value. When the integrated value exceeds the reference value, an alarm signal is generated. The number of disconnected lamps may also be determined and displayed.

Abstract: A non-light producing substitute apparatus for use as a replacement for a phosphor energizable lamp in an arrangement where a plurality of such lamps are connected in a series electrical circuit. Typically, two or more phosphor energizable lamps, such as fluorescent lamps, are connected to pairs of spaced apart sockets in a fixture and if one of the lamps is burned out or is removed, there is ineffective operation of the remaining lamp. The substitute apparatus permits one of the series connected lamps to be removed with the other to operate without substantially affecting lumen output of the remaining lamp and power factor loss. The substitute apparatus of the present invention is effective in that it does not necessarily create a connection between the two terminals in the pair of spaced apart sockets from which the lamp was removed.

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: An electronic ballast-inverter for multiple fluorescent lamps employs a push-pull inverter and a series resonant circuit for driving the lamps. The inverter operates at the resonant frequency of the series resonant circuit. Current in the resonant circuit is limited, for low-load conditions, in response to a sensing voltage which is used to lower the frequency of operation of the inverter, to make the load more reactive.

Abstract: A ballast circuit for driving a sodium vapor lamp includes a ballast transformer having a primary winding connected to a constant current power source. A secondary winding of the transformer is connected across the lamp. A high voltage oscillator responsive to the voltage across the lamp superimposes high voltage pulses across the lamp when the voltage across the lamp is above a predetermined level. A time delay circuit, triggered by the initial voltage across the primary winding when the power from the power source is turned on, opens a normally closed switch connected across the primary winding a predetermined time interval after the time delay circuit is triggered.

Abstract: A lamp simulator for use as a replacement for a phosphor excitable lamp, such as a fluorescent lamp in a plural lamp fixture. The fixture is typically one with socket-type connectors adapted to have at least two or more phosphor excitable lamps mounted therein. The lamp simulator replaces one or more of the illuminatable lamps in the fixture. The simulator comprises a lamp body or housing having end caps on each of the transverse ends and generally has a size approximately equal to a lamp it replaces. In one embodiment, a capacitor may be physically mounted on one of the end caps and is electrically connected to one of the terminals on the end cap and electrically connected to a terminal on the other of the end caps. Further, the caps may have a diametral size at least slightly greater than the lamp tube such that a plurality of lamps can be packed in a single container without a separate jacket for each lamp.

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: Electrical lamp ballast system for starting and operating fluorescent lamps with improved efficiency. 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. The system provides for reduced lamp current crest factor, thereby improving life and operating characteristics of the lamps.

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: 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 circuit for efficiently operating two arc discharge flashlamps. The lamps are series connected and directly coupled through series circuitry across an alternating current (AC) source. A storage capacitor is connected between the junction of the lamps and one terminal of the source. Trigger pulses are alternately applied to the lamps so that the storage capacitor is charged when one lamp flashes and discharged when the other lamp flashes. RC timing circuits energized by the AC source control the time of pulsed ignition of respective lamps with respect to the phase of the AC waveform of the source.

Abstract: A non-light emitting insert for a fluorescent lighting fixture is used in place of a fluorescent lamp to complete a plural lamp ballast circuit so that the ballast is effective to illuminate properly any remaining fluorescent lamp coupled therein. The insert appears externally as a conventional fluorescent lamp including end electrical terminations that fit in the sockets of a fluorescent lighting fixture, and to an extent the insert duplicates the electrical effect of a lamp in a two lamp ballast circuit. Using the insert a reduction in the light output and a substantially corresponding reduction in consumed electrical power are achieved for a plural lamp fluorescent lighting fixture arrangement while at the same time the components of the ballast circuit are operated at reasonably normal electrical and temperature levels.

Abstract: A compact integral permanently assembled lamp unit comprising a fluorescent lamp, resistor ballast, starter means, and end connectors for connecting a plurality of lamps together.

Abstract: A circuit arrangement for igniting at least one gas discharge flash tube having two main electrodes includes a chargeable flash capacitor connected in parallel with the flash tube and an electronic switch. These elements are connected to a voltage generator which supplies ignition voltage pulses and the electronic switch constitutes a gas discharge path for the flash tube. The voltage generator has such a low impedance, in particular a low inductance, that the ignition voltage pulses supplied thereby at least approximately adiabatically heat the gas discharge paths.

Abstract: A circuit arrangement for igniting flash tubes, without using an ignition electrode, and having two main electrodes which are supplied with an ignition pulse parallel to a flash capacitor and an electronic switch, employs an electronic switch which also constitutes a gas discharge path. In particular the electronic switch may be realized as a flash tube.

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.