Abstract: A constant-current power source unit has a variable power source which can adjust an output voltage. To detect a voltage applied to the gas discharge tube, a voltage detection unit is provided. A power source controlling unit configured to control the voltage by adding a predetermined voltage to the voltage taken in from the voltage detection unit after the electric discharge is started in the gas discharge tube.

Abstract: A uniform voltage is applied to loads even to other than a multiple of three loads made of heating lamps connected in parallel to each other, without causing any burden on a primary side. The number of loads is divided into a multiple of three and a multiple of two. A three-phase AC voltage is applied to three primary windings, which are connected as a Y-connection or a ?-connection. Secondary windings, which are each magnetically coupled to a primary winding of a plurality of three-phase transformers and have the same number of turns, are connected with the multiple of three loads.

Abstract: The present application relates to a lighting applications. In particular, the present application describes examples of lighting fixtures and light bulbs containing a light transmissive optic. The orientation of the solid state emitters together with the contoured output surface of the light transmissive optic produce a tailored light output distribution over a designated planar surface. The light generated by the solid state light emitters is of a sufficient intensity to illuminate the designated planar surface.

Abstract: A high efficiency light bulb has an outer globe with a base and a detachable bulb portion. The base has a base connection portion with a screw base and a control circuit with transformer for controlling and conveying electric power from the screw base to a quartz tungsten filament. The detachable bulb portion has an outer globe and an inner globe. At least the inner globe has a transparent infrared heat reflecting coating to improve efficiency by retaining heat within and reflecting the heat back on the filament. In another embodiment, the bulb and base are not detachable and the whole bulb is replaced when it reaches the end of its usefulness. A non-reactive gas such as krypton, bromine or xenon, for example, is used to fill the bulbs.

Abstract: By monitoring the temperature of an LED and the temperature of a controller chip for the LED, a thermal foldback control is employed to gradually decrease the driving current of the LED before the LED or the controller chip is over heated, so as to prevent an over temperature protection from being triggered to shutdown the controller chip to cause the LED to undesirably flicker.

Abstract: A ballast circuit includes a control loop to reduce a filament heating voltage below after the lamp filaments have been pre-heated. A filament cutback circuit includes a filament cut-back inductive component magnetically coupled to the resonant inductive component in the inverter to receive a filament cutback control voltage associated with an AC voltage for powering the lamps. During the pre-heating period, the filament cutback control voltage is not high enough to charge a chargeable component to a switch threshold level. However, during lamp ignition, the filament cutback control voltage is increased and charges the chargeable component to the switch threshold level. This causes a switch device to operate in a conductive switch state and the filament cutback circuit suppresses the pre-heat voltage.

Abstract: A multi-output electronic ballast is disclosed. The multi-output electronic ballast is used to drive a plurality of lamp assemblies and includes an AC/DC converter, a first inverter, a second inverter, an auxiliary voltage generator, and a control circuit. The AC/DC converter converts an AC input voltage to a high DC voltage. The first inverter converts the high DC input voltage to a first AC voltage selectively. The second inverter converts the high DC voltage to a second AC voltage. The auxiliary voltage generator generates an auxiliary voltage. The control circuit receives the auxiliary voltage generating circuit and outputs a control signal to the first inverter according to the switching operation of a first external switch. When the control signal is transmitted to the first inverter, the first inverter comes into operation and converts the high DC voltage to the first AC voltage.

Abstract: An electronic ballast circuit includes a filament drive circuit that can adjust the pulse width of a pulsed heating signal in accordance with the lamp current to a gas-discharge lamp. A logic device, such as an SR flip-flop, is used to control a switch that is coupled to the primary winding of a filament drive transformer coupled to the lamp filaments. The logic device opens and closes the switch device to generate the pulses of the pulsed heating signal and thus controls the pulse width of the pulses. A clock signal triggers logic device to start a pulse while the end of the pulse is determined by a signal level across a resistor in series with the primary winding of filament drive transformer. Once this signal level is at or above a threshold level, logic device switches the switch device to end the pulse.

Abstract: A system for operating a fluorescent light is provided. The system comprises: a fluorescent lamp with at least one electrode having at least one corresponding heating filament; a filament signal power supply for providing a filament current signal having a filament current frequency, the filament signal power supply connected to create a filament current through the at least one filament; and a plasma signal power supply for providing a plasma power signal having a plasma power frequency, the plasma signal power supply connected to create a plasma current between the at least one electrode and a gas contained in the fluorescent lamp. The plasma power frequency is greater than the filament current frequency.

Abstract: There is provided a method that can detect the lamp type of fluorescent lamps and operate the lamp at the appropriate lamp power. The proposed method involves the classification of lamp characteristics of existing fluorescent lamps and the use of logic detection method such as a fuzzy logic detection and control technique to zoom into the right type of lamp. The information used in the lamp detection includes (1) lamp filament/electrode resistance, (2) lamp voltage and (3) lamp current. These three pieces of information can be used to select the appropriate fluorescent lamp type so that the control gear can operate the lamp at the right rated power. The importance of this invention can lead to a universal electronic ballast that can detect and operate all fluorescent lamps commonly available. It can also be used in a limited capacity to control a limited range of lamps.

Abstract: A ballast module regulates power output to a fluorescent light. The ballast module includes a component. A temperature sensor senses temperature of the component. A control module adjusts power output to the fluorescent light based on the temperature of the component sensed by the temperature sensor. The control module adjusts power to the fluorescent light by reducing the power output to the fluorescent light or increasing the power output to the fluorescent light.

Abstract: The high-pressure discharge lamp lighting device of the invention includes a lighting circuit for supplying an alternating current to a high-pressure discharge lamp to cause lighting, the high-pressure discharge lamp having an arc tube in which a halogen material is enclosed and a pair of electrodes is disposed, and each electrode having a protuberance at a tip thereof. A frequency of the alternating current varies without dependency on operating data that varies as a lighting time of the high-pressure discharge lamp elapses.

Abstract: In accordance with one embodiment of the present invention, there is provided a switch-mode power supply to generate the heating current for a hot-filament electron-emitting cathode. The power supply directly couples, without an output power transformer, the output from a full-bridge converter that operates at an output frequency in the range from ten Hz to tens of Khz to the output terminals of the power supply. A connection to a reference potential that minimizes the potential fluctuation of the cathode is provided by the center tap on an autotransformer connected across the output terminals, where the conductors in the autotransformer are sized for half of the emission current from the cathode rather than the much larger heating current.

Abstract: The present invention relates to glow-switch starters 1, lighting devices therewith and use thereof. The glow-switch starter 1 is suitable for use with three phase supply voltages substantially higher than the common 230V supply voltage 26. This allows more efficient gas discharges in e.g. fluorescent lamps 20, and/or more lamp power, and/or less energy losses in ballasts 22 and lamp electrodes. To make the glow-switch starter suited for such use, according to the invention, the gas filling 5 of the starter 1 is adapted. An important criterion is that the glow current in the steady state operation of the fluorescent lamp that is started by the starter is small enough to prevent closing of the (bimetallic) switch.

Abstract: Methods and apparatus are provided for increasing the life of a fluorescent lamp suitable for use as a backlight in an avionics or other liquid crystal display (LCD). The apparatus includes a channel configured confine a vaporous material that produces an ultra-violet light when electrically excited. A layer of light-emitting material is disposed within at least a portion of the channel is responsive to the ultra-violet light to produce the visible light emitted from the lamp. An electrode assembly that electrically excites the vaporous material includes a first post, a second post, a conductive filament suspended between the first post and the second post and having a tail portion extending therebeyond, and a benign insulating material such as glass frit substantially covering the tail portion to prevent radio frequency (RF) emissions from the tail portion of the filament.

Abstract: An ultra-high pressure mercury lamp in which the tungsten comprising the electrodes is prevented from spraying during starting and operation, and blackening on the inside wall of the arc tube is prevented is achieved in that at least one of the electrodes has an axial part which is made essentially of tungsten and a starting part which is made essentially of tungsten, at least one of the axial part and of the starting part containing an electron emission material with a smaller work function than tungsten such that the value of S/A in mm2/% by weight is in the range 1?S/A?1×104, S in mm2 designating the surface area of the part of the electrode projecting into the arc tube containing the electron emission material and A in % by weight indicating the concentration of the electron emission material in this part.

Abstract: An exemplary electron emission device includes an electron emitter, an anode opposite to and spaced apart from the electron emitter, a first power supply circuit, and a second power supply circuit. The first power supply circuit is configured for electrically connecting the electron emitter and the anode with a power supply to generate an electric field between the electron emitter and the anode. The second power supply circuit is configured for electrically connecting the electron emitter with a power supply to supply a heating current for heating the electron emitter whereby electrons emit therefrom. Methods for generating an emission current with a relatively higher stability also are provided.

Abstract: An inductively powered gas discharge lamp including both a power coil and a heating coils associated with each filament. The heating coils enable the filaments to be preheated before the starting voltage is applied through the power coils. The inductive power coils and the inductive heater coils are contained within the lamp envelope, allowing the lamp to be entirely sealed. A method of dimming the lamp also is disclosed. The lamp is dimmed by both decreasing the power applied to the power coils and increasing the power applied to the heating coils so as to prevent the arc from extinguishing under lower voltage conditions.

Abstract: An inductively powered gas discharge lamp assembly having a secondary circuit with starter circuitry that provides pre-heating when power is supplied to the secondary circuit at a pre-heat frequency and that provides normal operation when power is supplied to the secondary circuit at an operating frequency. In one embodiment, the starter circuitry includes a pre-heat capacitor connected between the lamp electrodes and an operating capacitor located between the secondary coil and the lamp. The pre-heat capacitor is selected so that the electrical flow path through the pre-heat capacitor has a lesser impedance than the electrical flow path through the gas of the lamp when power is applied to the secondary circuit at the pre-heat frequency, and so that the electrical flow path through the pre-heat capacitor has a greater impedance than the electrical flow path through the gas when power is applied the operating frequency.

Abstract: A metal halide lamp includes a ceramic arc tube that is composed of a main body and two narrow tube parts provided at respective ends of the main body; a pair of electrodes provided inside the main body; two feeders, each being connected at one end thereof to a different one of the electrodes inside the main body, and extending through a different one of the narrow tube parts, so as to be external to the arc tube at another end; a starting wire that is connected to one of the feeders, and that is in a vicinity of or contacts an outer surface of the arc tube; and a current suppressing unit that is on a current path of the starting wire, and suppresses or cuts off current on the path.

Abstract: The object of the present invention is to provide a flash lamp unit with a long service life which allows a high radiant efficiency to be obtained and a flash radiation device demonstrating excellent flash radiant performance despite a small size, and the flash lamp unit comprises a flash lamp having mercury sealed in a discharge container, wherein preheating means is provided for preheating the flash lamp, the quantity of contained mercury in the flash lamp is in the range of 0.2 to 55 mg/cm3, and the flash lamp is ignited under the specified conditions, and the flash radiation device comprises the above-described flash lamp as a light source.

Abstract: An improved electron multiplier bias network that limits the response of the multiplier when the multiplier is faced with very large input signals, but then permits the multiplier to recover quickly following the large input signal.

Abstract: Herein described is a driver circuit of a fluorescent lamp having a first and a second electrode and igniting when the voltage between the first and second Electrode exceeds a given threshold voltage. The driver circuit comprises an inductance coupled to a supply voltage and to a terminal of the first electrode a first condenser coupled to the other terminal of the first electrode and to a terminal of the second electrode, a control device comprising a first and a second system of switches capable of guaranteeing oscillations of a voltage signal on the inductance and on the first condenser up to the ignition of the lamp. The driver circuit comprises a device associated to the control device and capable of acting on the first system of switches so as to regulate the frequency of the oscillations from a frequency greater than the resonance frequency of the inductance and of the first condenser to the same resonance frequency so as to guarantee a preheating of the first and second electrodes.

Abstract: A fluorescent lamp lighting apparatus includes a fluorescent light emitting tube; and an electronic lighting circuit for applying an electric current to the fluorescent light emitting tube. The electronic lighting circuit includes a pair of electrode filaments provided in the fluorescent light emitting tube, a pair of capacitors each connected in series to a respective one of the pair of electrode filaments and connected parallel to the fluorescent light emitting tube, and an inductor connected in series to one of the pair of electrode filaments.

Abstract: An electric lightbulb is provided for use with lightbulb sockets in either 110V or 220V screw type or bayonet circuits. The lightbulb includes a lamp portion and a cap portion, with the cap portion preferably containing circuitry. When the switch is on a high setting the lightbulb of this invention will last approximately twice as long as conventional incandescent bulbs, but at a low setting the bulb of this invention will last at least ten times as long as a conventional incandescent bulb. The lamp portion includes a filament attached to wires which are secured to the base of the lamp as well as to wires which are secured to an insulative sheath which is also held adjacent the base of the lamp. A metallic disk is maintained in contact with the sheath as well.

Abstract: A high-voltage discharge lamp has a bulb made of quartz glass, a pair of electrodes and molybdenum foils, wherein the pair of electrodes are arranged so as to oppose each other and are joined to respective ones of the molybdenum foils, and the bulb and molybdenum foils are hermetically sealed at seal portions of the bulb. The joints between the pair of electrodes and the respective molybdenum foils are covered by cylindrical members having slits on an outer surface and/or an inner surface thereof.

Abstract: Fluorescent tube type discharge lamp has end sealed in base with terminal pins connected to lead wires passing through stem press and supporting an electrode in the form of a coil having an emitter. Bimetal strip has a first end welded to one of the leads and a second end proximate to a thin walled portion of the stem. When electrode fails and an arc discharge operates directly off the leads, the bimetal strip heats up so that second end contacts thin walled portion and arcs through to admit air for passive failure of lamp.

Abstract: A planar fluorescent lamp having a resistive trace and optically transmissive cover electrodes is described. In one embodiment, the lamp includes an insulative lamp body with the transparent cover electrodes supported by the lamp cover. The resistive trace is supported by the base, either as an exterior resistive trace or within the lamp. The resistive trace acts as a heating element by producing heat in response to an electric current passed through the resistive trace. Because the resistive trace is in thermal contact with the lamp body, heat produced by the resistive trace heats the lamp, improving cold starting. The cover electrodes and, in some embodiments, the resistive trace, are used to control electric fields within the lamp body by applying voltage potentials between discrete cover electrodes or between the cover electrodes and the resistive trace. The controllable electric fields improve cold starting and uniformity of light during low light operation.

Abstract: A fluorescent light source includes a fluorescent lamp, lamp bases attached to opposite ends of the fluorescent lamp, and an electrically insulating substrate connected to the fluorescent lamp. A heating element is positioned on the fluorescent lamp, and a first and second pair of power traces are formed on the electrically insulating substrate. The first pair of power traces are connected to the heating element to provide power thereto. The second pair of power traces are connected to a pair of electrical conductors that provide power to the fluorescent lamp. This fluorescent lamp can be used in a replaceable fluorescent light source unit for a document scanner. The replaceable fluorescent light source unit includes a housing, lamp base receiving members attached to the housing, and registration notches to properly align the fluorescent lamp. Lastly, the fluorescent lamp source includes light blocking material to provide a uniform illumination profile along the length of the lamp.

Abstract: Operation of a vapor lamp light source for instrumentation utilizes a lamp manager controller for instant-on and precise temperature control to enhance and control output at specified wavelengths by monitoring and discriminating the spectral output of the lamp, and adjusting lamp current and temperature to maintain specific wavelength and light flux. Specific wavelengths can be selected and the wavelength automatically monitored for output level by control of a cold spot by an electrothermal device and a monitor. Lamp temperature, current and flux level at a selected wavelength are controlled.

Abstract: A fluorescent light source includes a fluorescent lamp, lamp bases attached to opposite ends of the fluorescent lamp, and an electrically insulating substrate connected to the fluorescent lamp. A heating element is positioned on the fluorescent lamp, and a first and second pair of power traces are formed on the electrically insulating substrate. The first pair of power traces are connected to the heating element to provide power thereto. The second pair of power traces are connected to a pair of electrical conductors that provide power to the fluorescent lamp. This fluorescent lamp can be used in a replaceable fluorescent light source unit for a document scanner. The replaceable fluorescent light source unit includes a housing, lamp base receiving members attached to the housing, and registration notches to properly align the fluorescent lamp.

Abstract: The method of conducting a lighting operation of a metallic vapour discharge lamp, to maintain a suitable arc tube temperature, even if the lamp is operated at an input power higher than 160 W/cm of lighting length. A metallic vapour discharge lamp, in which mercury, rare gas, iron and halogen are encapsulated wherein an arc tube is used and which is operated with an internal pressure of 0.5 to 10 psi, an input power of higher than 160 W/cm of lighting length and within a heater having an air injection cooling system. The lamp characteristics are D.ltoreq.28 and simultaneously P/D.ltoreq.14, where the arc tube external diameter is designated D (mm) and the input power/cm of lighting length is designated P (W/m).

Abstract: A light source device having a controlled current source that maintains a constant intensity of light from the source during changes in light source temperature, particularly at warm-up. The light source is heated to speed up warm-up and to maintain constant temperature of the source during operation under varying ambient temperatures. Control of the current to the light source is determined by the temperature profile circuit with signals via a temperature signal conditioner from a temperature sensor proximate to the light source. Control of the heater is ultimately dictated by temperature sensor signals.

Abstract: A CAM cell array for storing a logical address is divided into first to third CAM sections. A first partition switch circuit intervenes between a zeroth piece of sense line connected to a sense circuit and a first piece of sense line for the first CAM section. The sense circuit is a circuit for selecting a RAM cell array in which a physical address to be read out is stored. A second partition switch circuit intervenes between the first piece of sense line and a second piece of sense line for the second CAM section. A third partition switch circuit intervenes between the second piece of sense line and a third piece of sense line for the third CAM section. By controlling switching operation of respective partition switch circuits according to page size, optimum length of the sense line is utilized, thus achieving a high-speed address translation.

Abstract: A ballastless high pressure discharge lamp includes an arc tube, electrodes disposed in the arc tube, a column of mercury disposed in the arc tube and having a volume less than the volume of the arc tube, and cushion material disposed in the arc tube adjacent at least one of the electrodes. The cushion material comprises an inert gas impinging upon at least one end of the column of mercury. At least one of the electrodes extends into the column of mercury. The discharge lamp also includes a heating member disposed adjacent the arc tube to separate the column of mercury into two sub-columns by the vaporization of a portion of the mercury column to thereby form a space between the two sub-columns and compress the cushion material and allow one of the mercury sub-columns to engage one of the electrodes whereby to form an arc in the space between the two sub-columns of mercury.

Abstract: An electric lamp assembly includes a sealed outer envelope, an arc discharge tube mounted within the outer envelope, a safety filament connected in series with the arc discharge tube for extinguishing the arc tube within a predetermined time after the outer envelope is broken, and an electrically-insulating sleeve disposed around the safety filament. The insulating sleeve suppresses emission of electrons from the safety filament and thereby prevents a reduction in frame potential which would increase sodium loss from the arc tube. The insulating sleeve includes openings which permit air to reach the safety filament when the outer envelope is broken. A mounting arrangement includes a pair of mounting tabs which provide electrical connections for the safety filament and which approximately centers the safety filament in the insulating sleeve.

Abstract: A gas discharge tube comprises an indirectly heated cathode structure including a hot cathode into which a heater is incorporated. During discharging, the heater is supplied with a discharge current so as to generate Joule heat which is used as a heat source for the hot cathode. To this end, in a drive circuit in which the heater is preheated with a heater power source to initiate the discharging and to light up the discharge tube, followed by supply of discharging power from a discharging maintaining power source, a preheating switch is inserted between the heater and heater power source, and is opened at a start of the discharging and kept opened thereafter.

Abstract: A negative glow discharge lamp including an anode and an indirectly-heated cathode disposed within a phosphor-coated envelope. The cathode includes a heater filament surrounded by a metallic cylinder which is coated with an emissive material. The differential resistance of the heater filament is sufficient to internally ballast the flow discharge lamp.

Abstract: A modified impedance rapid start fluorescent lamp system is provided with interrupted cathode heating. This structure includes a circuit in parallel with one of the bimetal switches at each side of a cathode. The circuit includes a current limiting capacitor and bleeder resistor connected in parallel with each other and a third normally closed thermal bimetal switch.

Abstract: An AC polarity-reversing bridge ballast for an arc discharge lamp using an incandescent filament for resistive ballasting and standby illumination powers the filament during hot restart without modifying the low duty cycle operation of the starting oscillator and without introducing additional power switches. The switching elements of the polarity-reversing bridge serve the dual functions of reversing the polarity of the voltage supplied to the arc lamp during normal running conditions and energizing the filament during a restart condition.

Abstract: A fluorescent lamp electrode heat cutout switch is provided for placement within a fluorescent lamp stem and outside the discharge envelope and is configured such that a resistive heater wire is connected to one electrode lead-in and a bimetallic switch element is connected to the other electrode lead-in and configured upon an insulating support in such fashion that the heat cutout switch receives heat from the resistive heater to activate the switch so that the electrode heat is cut off when the lamp starts and is kept off during normal lamp operation.

Abstract: A three (3)-way lamp having a tungsten halogen-cycle inner envelope and an operating circuit for the inner envelope is disclosed. The operating circuit comprises a ballast element and two diodes lodged within the confines of the base of the lamp. The operating circuit allows the inner envelope to provide three different levels of illumination for the lamp while still maintaining the desired operation of the halogen additive within the inner envelope.

Abstract: A ballast circuit arrangement for providing a predetermined desired A.C. voltage to enhance the operation of the gas discharge tube serving as the main light source in a lighting unit of the type which also comprises an incandescent filament serving as a resistive element and a supplementary light source is disclosed. The circuit arrangement operates directly from an applied 220 volt, 50 Hz or 120 volt, 60 Hz alternating current (A.C.) voltage source. The circuit arrangement comprises a capacitor connected serially with both the incandescent filament and the gas discharge tube. If desired, the incandescent filament may be replaced with a resistive element. The value of the capacitor is selected so as to reduce the applied 220 volt, 50 Hz or 120 volt, 60 Hz A.C. source to a desired range for operating the circuit in a manner to develop a desired reduced voltage for operation of the gas discharge tube.

Abstract: A lighting unit having a filament serving as a supplementary light source, an improved gas discharge tube serving as a main light source having improved electrodes and an improved ballast circuit operating in cooperation with the improved electrodes is disclosed. Various embodiments of the improved electrodes and various embodiments of the improved ballast circuits are disclosed. The improved ballast circuit operating in cooperation with the improved electrodes provides for thermionic arc conditions in the operation of the gas discharge tube substantially immediately after the application of voltage applied to the unit.

Abstract: A discharge lamp is provided with a resistive ballast together with means for sensing lamp voltage conditions. If the lamp voltage exceeds a predetermined threshold then a control circuit operates to apply the output of a relatively high frequency oscillator to the lamp to achieve lamp re-ignition which must be accomplished twice during each alternating current cycle. Lamp re-ignition is necessitated by lamp current zero-crossing which occurs as a result of powering the lamp from an alternating current energy source.

Abstract: Apparatus for use with a fluorescent lamp having a longitudinal axis and a filament winding at each end includes a pair of terminals formed for connection to a potential source with means for connecting one of the terminals to a filament winding, an incandescent lamp coupling the other terminal to the filament winding at the other end of the fluorescent lamp, a starting aid extending along the longitudinal axis of the fluorescent lamp and an impedance coupling the starting aid to the junction of the incandescent lamp and a filament winding of the fluorescent lamp.

Abstract: In a metal vapor discharge lamp for operating it by high voltage generated in the actuation of a heat sensitive switch means in an outer bulb, a relatively low pressure of a sealed gas or mercury is sealed in the outer bulb to operate the heat sensitive switch means in the gas atmosphere to control the surge voltage to a desired degree whereby the discharge lamp is operated without failure and the insulation breakdown of a ballast and an operation circuit is prevented.

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: The present invention relates to a lighting unit having low and high light levels and employing an efficient arc lamp as the source of light during the high level setting. The unit employs a filamentary light source for the production of light during low light level operation, the filament acting as a resistive ballast for the arc lamp during high level operation. Practical embodiments operate in a conventional three-way light socket with the sequences being off, low, high and low, and off, low, high, and high.

Abstract: A high efficiency controlled direct current source for operating high pressure mercury or metal halide lamps for use as substitutes for ordinary incandescent lamps. The circuit includes a voltage sensitive circuit for pulsed starting of the arc discharge lamp as well as for the activation of an auxiliary incandescent filament during the warm-up or hot restart of the arc.