Abstract: A series-resonant ballast for powering at least one gas discharge lamp (16) having heatable filaments (12,15) includes: DC voltage input terminals (B+,B-); an oscillating resonant converter (55,26,51,52,53) for producing high frequency voltage for application to the gas discharge lamp; a control circuit (58) able to receive a control signal from the DC input terminals and from the resonant converter and operable to initiate and stop the oscillations; and direct current blocking circuits (57,50) coupled across the filaments (12,15) and operable to stop flow of the control signal from the DC input terminals, thereby the ballast will not oscillate and will not draw any power from the DC input terminals, whenever the gas discharge lamp is: (i) removed from the output terminals, (ii) is defective, or (iv) is inoperative.

Abstract: In a fluorescent lamp ballast, a high-frequency AC voltage is applied directly across a tuned L-C circuit. The fluorescent lamp is connected in parallel with the capacitor of the L-C circuit and a voltage-limiting means prevents the series-resonating L-C circuit from overloading the source of AC voltage during any period when the lamp is not effective in providing circuit loading. When power is initially applied to the L-C circuit, a control means provides a short circuit across the capacitor; and, by way of a first current transformer, the resulting short circuit current is used for pre-heating the fluorescent lamp cathodes. After about 1.5 second, the control means provides for removal of the short circuit for a period of about 25 milli-seconds, thereby permitting the voltage across the capacitor to grow to a magnitude sufficient to ignite and operate the lamp, while at the same time removing the cathode voltage.

Abstract: A high intensity discharge ballast having an ignitor which shuts off after a predetermined time period has elapsed. The ballast is sensitive to voltage dips in power line voltage and resets a timer whenever the power line voltage drops below a level sufficient for lighting a lamp load. Restart of the lamp load immediately following restoration of power line voltage is achieved without requiring that the power line voltage be removed from the ballast or otherwise reduced to approximately 0 volts before restart can be initiated.

Abstract: An embodiment of the present invention is a ballast for a high intensity discharge lamp that includes a non-automatically resetting thermal protector thermally coupled to a coil wound on a core and insulation between the coil and the core. Only one cycle is allowed into what may be a range of temperatures capable of destroying the insulation within the ballast.

Abstract: A dual mode high intensity aircraft approach lighting system includes a plurality of lights interconnected by means of power wiring. An improved subsystem for detecting lamp failures is disclosed which permits a positive identification of individual failed lamps at a remote location, such as the control tower of an airport, for instance. The subsystem hardware consists of an operational monitor processor, three lamp controllers, one for each of three lighting loops, one remote lamp transceiver module per lamp, and existing ac loop wiring. The operational monitor processor board initiates a reset of the lamp controller and remotely installed transceiver units by sending a SAMPLE ALL signal to each lamp controller. A comprehensive test of all lamps in each of the three lighting loops is performed. The first lamp controller board sequentially polls each lamp for operational status in the first loop.

Abstract: A power source device includes a voltage converting means to input side of which a DC voltage source is connected and to output side of which a capacitance element and a load circuit are connected, while a control circuit is connected to the voltage converting means and the load circuit, the latter circuit having a load impedance made lower upon starting of a load in the load circuit than that in stable lighting of the load, wherein such control constant as oscillation frequency and duty are made to be substantially constant at the time of the starting and stable lighting of the load, and a switching means in the voltage converting means is turned OFF when the capacitance element has a voltage below a predetermined value.

Abstract: An embodiment of the present invention is a lighting system including a sense transformer with two primaries and a secondary for receiving alternating current (AC) from a power source, a low ohmage resistor placed across the sense transformer secondary winding for preventing saturation of the core of the sense transformer, an analog comparator for detecting when ground-fault signals in the sense transformer secondary winding exceed a threshold voltage and digital counters for testing whether or not a ground-fault condition persists longer than three consecutive half-cycles of the received alternating current from the power source.

Abstract: A power supply circuit for a neon tube includes a step-up power transformer having a primary winding connectable to a power source, a secondary winding to which the neon tube is connected, and an auxiliary winding which is used to sense if the secondary winding is loaded or not and develops a control voltage proportional to current flowing through the neon tube, the control voltage maintaining a relay operated so that the primary winding of the transformer is connected to the power source in the absence of load fault conditions, a load fault condition causing the control voltage to decrease below the level required to maintain the relay operated, so that the primary winding of the transformer is disconnected from the power source, interrupting high voltage in the secondary winding of the transformer.

Abstract: The present invention is directed to an electronic ballast device for the control of gas discharge lamps. The device is comprised of a housing unit with electronic circuitry and related components. The device accepts a.c. power and rectifies it into various low d.c. voltages to power the electronic circuitry, and to one or more high d.c. voltages to supply power for the lamps. Both the low d.c. voltages and the high d.c. voltages can be supplied directly, eliminating the need to rectify a.c. power. The device switches a d.c. voltage such that a high frequency signal is generated. Because of the choice of output transformers matched to the high frequency (about 38 kHz) and the ability to change frequency slightly to achieve proper current, the device can accept various lamp sizes without modification. The ballast can also dim the lamps by increasing the frequency. The device can be remotely controlled.

Abstract: The method of igniting a gas-discharge lamp includes the steps of generating an exciting signal T in an operating circuit having an AC voltage generator on receipt of a lamp switch-on signal E by the operating circuit; exciting an ignition resonant circuit connected to a gas-discharge lamp with the exciting signal T to produce a decaying oscillating process, advantageously a decaying oscillating voltage, in the ignition resonant circuit; determining a resonant frequency of the ignition resonant circuit from the decaying oscillating voltage or process with a signal processing circuit, advantageously a microprocessor, connected to the ignition resonant circuit and operating the AC voltage generator at the determined resonant frequency by controlling the AC voltage generator with the signal processing circuit. The apparatus can be shut off or a warning signal generated when a predetermined parameter of the decaying oscillating process is exceeded.

Abstract: Apparatus for operating a discharge lamp comprising a high frequency circuit, sensing means for sensing the absence of an electrical connection between the circuit and the lamp and control means for receiving a non-connection signal and for sending a decrease control signal to the high frequency circuit for decreasing the high frequency power supplied to the lamp in response to the non-connection signal. The sensing means senses the absence of an electrical connection between the circuit terminal to which an electric potential is applied which is less than that applied to the other circuit terminal. By sensing the electrical non-connection between the circuit terminal having the lower potential, it is not necessary to sense the absence of a connection at the other end of the lamp.

Abstract: An anti-cycling device for high pressure sodium lamps detects an abnormal cycling condition by using a fiber-optic cable that extends between an anti-cycling controller board and the lamp itself. An outer end of the cable is arranged so that light emitted by the lamp will be transmitted to the controller board. A photocell mounted on the controller board, at the other end of the cable, transmits a variable magnitude electrical signal to the circuitry on the controller board. The signal varies in accordance with light being transmitted or not transmitted through the cable, as the case may be, corresponding to a cycling condition. In this manner, the controller board is able to detect a cycling condition, and thereby cause the power supply to the lamp to be cut off.

Abstract: A circuit for starting and operating a discharge lamp, such as a compact fluorescent lamp, at high frequency from an 60 Hz AC supply. The circuit includes a DC power supply coupled to a pair of AC input terminals for generating a DC voltage. An oscillator coupled to the DC power supply includes a drive transformers having a primary winding. A load coupled to the output of the oscillator comprises a series combination of the primary winding of the drive transformer and a tank circuit including a tank inductor and a tank capacitor. Suitable means for connecting a discharge lamp in parallel with the tank capacitor is provided. A voltage sensing circuit responsive to failure of the lamp, is coupled to an oscillator controlling circuit which reduces the output of the oscillator after a predetermined time delay by shunting the drive transformer. Upon replacement of the failed lamp, normal operation of the oscillator is resumed without having to disconnect the AC supply.

Abstract: The invention disclosed here is an anti-cycling device for high-pressure sodium lamps. A current sensor continually monitors lamp current and outputs a low voltage signal to an amplifier. When lamp current increases, indicating a starting or recycling condition, the sensor's voltage output correspondingly increases, and the amplifier responds by amplifying such output and transmitting it to a second amplifier. The latter acts as a voltage comparator and compares the first amplifier's output with a threshold level. Each time the first amplifier's output exceeds the threshold, the second amplifier outputs a trigger signal. Such signal is counted over time, and if the number of counts reaches a certain number, the counter outputs a malfunction signal to a relay that cuts off power to the lamp. An easy-to-see LED simultaneously illuminates to indicate the cycling condition and the need for lamp maintenance.

Abstract: An electronic ballast which will repeatedly try to ignite gas discharge lamps should they fail to ignite under conditions in which they should have ignited together with means rendering said electronic ballast incapable of trying to ignite said lamps after a predetermined period and said electronic ballast being rendered capable of again trying to ignite said lamps under prescribed conditions.

Abstract: An ignitor circuit for a discharge lamp is controlled by a timer to shut-off ignition pulses after a predetermined time if the lamp does not ignite. The timer is controlled by the application of power to the input line. Means in the lamp housing allow the timer to be manually reset during a hot relamping operation.

Abstract: A lighting circuit for a metallic halide lamp for vehicular headlight applications is disclosed. Included are a pair of input terminals between which a battery is connected for feeding the lamp via a normally open relay switch which is closed upon energization of an associated relay coil. The relay coil is connected in series with an operator actuated lamp switch and a protection switch, so that both lamp switch and protection switch must be closed to energize the relay coil and hence to close the relay switch. The protection switch is automatically opened to deenergize the relay coil when the battery develops overvoltage or when the lamp will not glow upon closure of the lamp switch. In an alternate embodiment, the protection switch is also opened in response to the development of overcurrent or overvoltage by a d.c. voltage booster circuit included in the lighting circuit.

Abstract: A torch particularly for use in hazardous conditions has safety and battery power warning features. The supply from a power source (34) to a light source (12) includes a frangible conductive element (132) in the conductive path to the light source (12). The conductive element (132) is provided on a torch glass (128), so that if the glass (128) breaks, the power supply to the lamp (12) will be cut off, thereby eliminating the risk of sparks, and exposure of the hot lamp element to the atmosphere. The torch also has a switch (22) and relays (38, 40) enabling batteries of the power source (34) to be switched between series and parallel arrays, enabling the torch to operate at full or low power. The torch also has a battery voltage sensing and indicating means, which cause the light source (12) to flash when battery voltage reaches a first predetermined level, and for the light source (12) to be switched off permanently when battery voltage reaches a second predetermined level.

Abstract: A disabling circuit for deactivating a high pressure sodium lamp starting and operating circuit when the lamp exhibits end-of-life cycling includes a normally closed thermal switch connected to the starting and operating circuit is inoperative, the switch having contacts which open in response to an elevated temperature. A heating element is connected in parallel with the lamp so that the voltage across the lamp is applied to the heating element. The heating element is supported in a selected heat conducting relationship with the thermal switch so that a predetermined elevated temperature is reached and the contacts are opened only after the dissipation of an amount of energy resulting from repeatedly high lamp open-circuit voltage accompanying end-of-life cycling.

Abstract: An indicator lamp indicates the status of an electrically-powered load control system by providing dim light when the load power is off and a brighter light when the load power is on. In another embodiment, the lamp not only provides two levels of light to indicate whether or not power is on, but also provides a repetitive flash when power to the system is being controlled by remote control. The indicator lamp can also indicate a break in the load circuit. Depending on the embodiment, the break can cause the lamp to be either off or flashing, regardless of the position of the load power switch. Alternatively, a break in the load circuit can cause the lamp to provide substantially no light if the load power switch is in the "off" position, with full light in the "on" position.

Abstract: An electronic ballast provides a high-frequency current-limited voltage between a first socket terminal and a second socket terminal. These socket terminals are adapted to receive and hold a rapid-start fluorescent lamp. The first terminal has a relatively low-magnitude potential with respect to ground; the second terminal has a relatively high-magnitude potential with respect to ground. A person causing in direct or indirect contact with the second terminal is apt to receive a hazardous electric shock. A self-oscillating electronic inverter is operable to provide the high-frequency voltage. To provide an output, this inverter has to be triggered into oscillation. However, if no current flows from the first terminal, the inverter will automatically become disabled within 25 milli-seconds; whereafter it will not be re-triggered for about 1.5 seconds.

Abstract: An electric lamp is provided having an outer envelope or jacket with a lamp base attached thereto, the lamp base having an aperture extending therethrough. A sealed inner capsule is supported within the outer envelope and electrically connected to the lamp base and to an electrically conductive elongated member one end of which engages an inner wall of the outer envelope and an opposite end of which extends through the aperture in the lamp base. A spring is provided which urges the one end of the elongated member against the inner wall and which will urge the opposite end of the elongated member out of the aperture if the envelope is broken thereby disconnecting voltage to a lead of the inner capsule.

Abstract: A starter controller for a multiple parallel ballast for high pressure sodium lamps detects lamp "drop-out" or 'cycling" and enables restarting of the lamp if the drop-out was causded by line transients of a level sufficent to cause normally operating lamps to drop-out. If the detected lamp drop-out was caused by normal end-of-life conditions, the controller does not allow restarting of the lamp. In one embodiment, the starter controller constantly monitors the voltage across the lamp terminals. When lamp drop-out occurs, this voltage rises rapidly to the ballast open-circuit secondary voltage. This voltage is detected by a level detector and rate detector which then processes lamp voltage level and rate of change of voltage after the initial drop-out is sensed.

Abstract: Circuitry for limiting a high frequency current through a load including a DC voltage source connected to a circuit ground; an inverter for converting the DC voltage to the high frequency current, the inverter being connected to circuit ground; a chassis containing the voltage source and the inverter where the chassis is connected to earth ground and where earth ground and circuit ground are at different electric potentials; sensing circuitry connected between earth ground and one of the output terminals of the voltage source to establish a current path from earth ground to the one output terminal of the voltage source to thus monitor any high frequency current which may flow through a person, for example, connected between one of the output terminals of the inverter and earth ground; and limiting circuitry for limiting the high frequency current through the person in response to the current through the person exceeding a predetermined limit.

Abstract: A ballast circuit for a fluorescent light bulb of the type having an elongated envelope with an electrode at each end. The ballast circuit includes a square wave generator which generates a square wave in excess of 10,000 hertz. The output from the square wave generator is used to modulate a voltage from a power source having a voltage in the range of 400-800 volts so that the modulated voltage has a frequency equal to the square wave frequency. The resulting modulated voltage is then electrically connected to the electrodes of the fluorescent lamp which illuminates the lamp.

Abstract: Apparatus for inactivating the source of microwaves for an electrodeless lamp to prevent accidental release of microwaves into the environment as a result of failure to assemble the lamp with a conductive mesh. An electrodeless lamp which is provided with a gas manifold for directing a stream of cooling gas against a lamp envelope is provided with a gas leak passageway which is blocked when the conductive mesh assembly is in place. A pressure switch in fluid communication with the gas manifold is activated and prevents operation of the microwave source when pressure is reduced as a result of gas leaking through the gas leak passageway.

Abstract: Subject invention relates to a fluorescent lamp ballast that is intended for safe and cost-effective use in lighting systems wherein the power to the various lighting fixtures is provided from a central source of relatively high frequency (Ex: 30 kHz) AC voltage. The ballast consists of a resonant series-circuit of an inductor and a capacitor--with the fluorescent lamp connected in parallel with the capacitor. Due to series-resonant action, if the lamp should happen to be non-connected or non-functional, and if proper precautions are not taken, the magnitude of the voltage developed across the capacitor may become so large as to cause damage to the circuit components and/or even to the source. To prevent such circuit damage, yet providing for a lamp starting voltage of suitably large magnitude and for an adequately long time, a Varistor voltage-limiting means is connected in parallel with the capacitor and a thermally actuated circuit breaker is connected in thermal contact with the Varistor.

Abstract: A dimmer control circuit having time constant regulating means provided in a multivibrator for regulating the load time ratio of the output pulse signal of the multivibrator to control ON, OFF the voltage of a battery applied to a lamp by the output pulse signal to thereby regulate the luminous intensity of the lamp comprising stopping means provided in the multivibrator for operating near the end of the regulation in a direction for increasing the luminous intensity of the lamp by the time constant regulating means and stopping the operation of the multivibrator. Thus, the dimmer control circuit can stop the operation of the multivibrator near the end of regulation in a direction for increasing the luminous intensity of a lamp to control the connection of a battery directly to the lamp with a fine current.

Abstract: A neon sign circuit is disclosed having a neon tube forming the lighted portion of the sign, a source of electrical power, and a high voltage transformer between the electrical power source and the neon tube. The circuit also includes a neon sign circuit malfunction detector circuit. This circuit includes a ground fault detector connected in the circuit between the source of power and the transformer, to ground, and to the neutral load side of the primary windings of the transformer. A pair of adjustable spark gaps are each connected to one of the secondary windings of the transformer between the transformer and the neon tube. A light source is connected between each spark gap and ground and light sensitive resistors are positioned adjacent to each light source.

Abstract: A switching arrangement for ignitio of a high-pressure discharge lamp, The switching arrangement is provided with means for suppressing the production of ignition pulses in case the lamp has ignited or in cast it fails. The switching arrangement comprises a pushpull circuit which is supplied on the one hand by the supply voltage and on the other hand by the voltage across the lamp. An output terminal of the push-pull circuit is connected to the means for suppressing the production of ignition pulses. Thus, it is achieved in a simple manner that the lamp voltage influences the blocking and activation of the production of ignition pulses.

Abstract: For use with apparatus of the type including a power supply, means operated by the power from the power supply and means operably connected between the power supply and the means operated thereby for applying power of a predetermined magnitude for operating said operated means circuitry and method wherein a resistor is connected to the apparatus and cycling limiting circuitry is connected across the resistor and is responsive to the voltage drop thereacross when the operated means cycles, i.e. turns off and then on. The cycling limiting circuitry counts the number of cycles and after a predetermined number of cycles occurs provides an output which is effective for interrupting power from the power supply, whereby the operating means is removed from the circuit to protect the latter from damage due to unlimited cycling.

Abstract: A two-filament incandescent lamp and operating circuit well suited to lighting applications requiring high service reliability. In the lamp, the rated operating voltage of the second filament is greater than that of the first filament. In the operating circuit, there is an inductive reactance in series with the lamp and, in one aspect of the invention, an electrical connection across the lamp terminals for measuring the operating voltage of the lamp. After the power and rated wattage of both lamp filaments have been selected, matched values of inductive reactance and open circuit voltage of the operating circuit can be uniquely determined such that the following advantages are obtained. When the first lamp filament fails, the second filament comes into full brilliance. In a preferred embodiment of the invention, there will be no significant change in the luminous output of the lamp before and after failure of the first filament.

Abstract: A discharge lamp monitoring and deactivating circuit includes a normally closed switch in series with the discharge lamp and its ballast and a detector circuit connected across the lamp to monitor lamp operating voltage. The detector circuit includes a capacitor which is charged and discharged through separate paths so that a lamp electrical waveform change waveform can be detected, resulting in a net charge. The charge is used to open the switch after a time delay which is only manually resetable.

Abstract: An improved dimmer apparatus which can protect an output power transistor for a lamp of a load when the lamp is short-circuited and which can eliminate manual operation for restarting the apparatus after recovery of the short-circuiting of the lamp. The apparatus comprises a detecting circuit which detects short-circuiting of the lamp to turn the transistor off. After lapse of a predetermined interval of time given by a timer circuit, the transistor is turned on to detect whether or not the lamp is still short-circuited. If the lamp is still short-circuited, the transistor is again turned off and then a same sequence of operations will be repeated until it is detected that the short-circuiting of the lamp has been recovered and thus a normal operation of the apparatus is restarted.

Abstract: A starting, hot restarting and operating circuit includes a pulse circuit for applying high voltage pulses to an HID lamp for starting or hot restarting. After a set interval of pulses if the lamp has not ignited, the pulse circuit is turned off for a selected inactive interval after which pulses are applied to the lamp again. If ignition does not occur after several active/inactive cycles, the circuit is deactivated until reset by turning the power off and on.

Abstract: A thermal protection device for a dual input voltage lighting fixture apparatus which includes a reversible connector for coupling either of two possible input voltages to the appropriate terminal of a winding of a transformer/ballast apparatus via a normally closed contact of a heat responsive thermal switch having a heating element electrically coupled to the reversible connector and thermally coupled to the closed contact. The latter contact opens in response to a level of heat above a given value. The transformer winding has two connection terminals, one of which is a tap point, connected to the reversible connector. The connection scheme provides the same energizing voltage to the heating element for each of the two different possible levels of the input voltage. The apparatus will automatically indicate if the connector is reverse connected for either of the two input voltages.

Abstract: A metal vapor discharge lamp has a burner for sealing xenon gas, mercury and a light-emitting additive in a translucent ceramic tube, a starting device of a thermal switch type which has a series circuit of a thermal switch and a coil filament and which is connected in parallel with the burner, and an outer envelope for sealing the burner and the starting device therein. In the lamp, the following inequalities must be satisfied:13.3.ltoreq.P.multidot.(B/A).ltoreq.6650.05.ltoreq.d.ltoreq.0.122,200.ltoreq.T.ltoreq.2,800where A is the volume (cm.sup.3) of the outer envelope, B is the volume (cm.sup.3) of the burner, P is a gas pressure (Pa) at room temperature of xenon sealed in the burner, d is a diameter (mm) of the coil filament, and T is a temperature (K) of the coil filament during operation.

Abstract: A circular fluorescent lamp assembly having the entire ballasting circuit, along with a thermal protector, contained within the assembly's lamp holder. The thermal protector serves the dual function of preventing permanent damage to the assembly's ballast means and for extending lamp starting switch means operating life under normal end of lamp life cycling conditions. The thermal protector is responsive to the coil temperature of the ballast means and is electrically coupled in series with the ballast means, starting switch, capacitor and the lamp. One example of the thermal protector is a bimetal bottle switch.

Abstract: Subject invention constitutes a low-voltage limited-power (Class 2) fluorescent lighting system consisting of the following principal component parts: (a) a power-line-operated inverter power supply that provides a power-line-isolated voltage output of relatively low but substantially constant magnitude (30 Volt RMS) and relatively high frequency (30 kHz); (b) electronic means for preventing the power supply current output from exceeding a pre-determined relatively modest magnitude (8 Amp RMS); (c) a number of fluorescent lighting units, each unit consisting of one or more fluorescent lamps and a corresponding high-frequency ballasting means being adapted to be operated at a high power factor from the voltage output of said power supply; and (d) a pair of conductor wires connected with the output of said power supply and adapted to permit a number of said fluorescent lighting units to be connected in parallel across said voltage output at various points along said pair of wires.

Abstract: The invention is directed to a method of preventing cathode damage when switching on an electron gun having a field emission cathode assembly including a cathode, a first electrode and a ground electrode. During normal operation of the electron gun, an extraction voltage is applied across the cathode and the first electrode and an accelerating voltage is applied across the cathode and the ground electrode. A direct galvanic connection is established between the cathode and the first electrode prior to normal operation of the electron gun. During a burn-in period, only the accelerating voltage is applied. This accelerating voltage may include an overvoltage of up to twenty percent. Then the galvanic connection between the cathode and the first electrode is interrupted and the extraction voltage is applied. An arrangement for carrying out the invention is also disclosed.

Abstract: A power distribution system consists of an inverter means providing power to a plurality of separate outputs, with each separate output being protected by its own individual overload protection means. In case more than a pre-determined rate of power has been drawn from one of these separate outputs for longer than a pre-determined time, the associated individual overload protection means acts to remove the power from this particular output--without affecting the other outputs. However, if for some reason the individual overload protection means for that particular output fails to operate within the pre-determined time, a second overload protection means operates to disable the inverter, thereby to remove power from all the separate outputs.

Abstract: An irradiation device including a series arrangement of an ultraviolet radiation source (5), a first switch (3) and a second switch (4). Under normal conditions the radiation source (5) is switched on and off by the first switch (3). The second switch (4) is operative only if the first switch (3) fails. By means of a simple circuit (7, 20, 17, 6; R), the defective device cannot be switched on again.

Abstract: A rapid start fluorescent lamp having a glass envelope with a phosphor coated inner surface, a low pressure gas fill and an electrode at each end includes at least one electrode disconnected switch having a bimetal switch normally closed at room temperature and open at a predetermined temperature higher than room temperature with the bimetal switch connected to the electrode and to an electrical lead extending from the lamp to an energization source.

Abstract: With many fluorescent lighting fixtures, the voltages required at the sockets to start and operate the fluorescent lamps are so high as potentially to constitute a substantial electric shock hazard to persons having to service such fixtures. To mitigate this hazard, whenever socket voltages exceed certain levels, protective measures have to be provided.Subject invention constitutes an electronic means for removing the socket voltages from a fluorescent lighting fixture in cases where a lamp is removed from one of its sockets.The invention relates to situations wherein inverter-type ballasting is being used, and involves the use of an electronic means for disabling the inverter whenever the ballast has provided the relatively high output voltage required for lamp starting for a period longer than that normally required for the lamps to start. However, if the lamps do start within the normally required time period, thereby causing a reduction in the output voltage, the disabling of the inverter will not occur.

Abstract: An energy-saving instant-start series-sequence fluorescent lamp system includes power-reducing capacitor means connected in series circuit arrangement with one or both lamps in a two-lamp system. A protective device is connected in circuit with a first lamp of the system so that in the event the second lamp fails to operate and causes a high current to flow through the first lamp, the protective device reacts to prevent the system from being damaged. A lamp incorporating the power-reducing capacitor and protective device is also disclosed.

Abstract: A cycling cut-off arrangement protects a ballast-starter circuit of a luminaire of the type having a high pressure sodium lamp from damage in the event of a cycling malfunction by sensing the change in power factor across the lamp during cycling, and disabling the ballast-starter circuit from its power source once cycling has been reliably detected. The method of sensing the power factor change, and of disabling the ballast-starter circuit is also disclosed, as well as a method of installing the arrangement on the luminaire with minimum retro-fitting required.

Abstract: An incandescent lamp possessing a ballast circuit comprising a resistor and capacitor in parallel further includes means for interrupting the connection between the ballast and external contacts provided on the base of the lamp. This interruption occurs upon removal of the lamp from its matching socket to prevent the occurrence of capacitor voltage across the external lamp contacts. The circuit is again closed upon reinsertion of the lamp in the matching socket to permit normal lamp operation.

Abstract: For protection against potentially serious electric shock hazard to a person removing and/or replacing a fluorescent lamp in a fluorescent lighting fixture having an inverter-type electronic ballast, a special protection circuit is provided as part of this ballast.This protection circuit operates to disable the ballast inverter within about one second after a fluorescent lamp is removed from at least one of its sockets, thereby removing the potentially hazardous voltage present at the fixture's lamp sockets.

Abstract: An intrinsically safe lighting system for energizing fluorescent lamps and the like in potentially flammable or explosive atmospheres is disclosed wherein one or more intrinsically safe power supply modules embody current monitoring and diverter circuitry, operable, upon the occurrence of abnormal circuit conditions such as a short or open circuit, to interrupt the lamp power supply and divert energy therefrom so rapidly that non-intrinsically safe sparking and ignition of the flammable atmosphere is avoided.

Abstract: A compact electronic assembly operable to control the energization of an electrical appliance is adapted for convenient mounting in an existing, standard electrical wall-switch box. A disconnectable electronic control means is mounted on the outside of the switch face plate and communicates with circuitry inside the wall-switch box by means of a plug-in connection through the aperture of the switch face plate. According to one aspect of the invention, a programmable electronic timer-switcher comprises a mounting plate which is secured to the opening of the wall switch box. A multiple-conductor receptacle is secured to the mounting plate, which also preferably serves as a heat sink for a switching means such as a triac. The receptacle is aligned behind the rectangular aperture of a standard switch face plate to permit plug-in connection to a programmable electronic timer disposed exteriorly of the face plate.