Abstract: A negative glow fluorescent lamp includes a light-transmissive envelope enclosing a fill material which emits ultraviolet radiation upon excitation, a phosphor coating on an inner surface of the envelope, the phosphor coating emitting visible light upon absorption of ultraviolet radiation, a cathode located within the envelope for emitting electrons, first and second cathode leads extending through the envelope, an anode located in the envelope and spaced from the cathode for collecting electrons and first and second diodes coupled between opposite ends of the anode and the first and second cathode leads, respectively. The glow lamp can include one or more insulating discharge barriers which surround the cathode and block electron bombardment of the cathode during positive half cycles of the AC voltage. The discharge barriers are preferably as large in area as is practical and can be coated with an ultraviolet-reflecting material or with a phosphor layer.

Abstract: A tester simulates high energy pulses typically present at the inputs to an avionics device after an aircraft carrying the avionics device has been struck by lightning. The tester is used to assist in determining whether the avionics device is sufficiently protected against the effects of a lightning strike on the aircraft. The tester includes a trigger circuit for generating trigger signals at fixed or random intervals so that the pulses which make up each burst as well as the bursts themselves are generated at fixed or random intervals. A number of individual pulse generating circuits are provided to generate high energy pulses which are output to the avionics device under test. A sequencing circuit feeds the trigger signals to the pulse generating circuits so as to generate the high energy pulses and bursts at the selected fixed or random intervals.

Abstract: A negative glow discharge lamp of small size comprising a cylindrical discharge container enclosing at least rare gas, a hot cathode disposed in the discharge container and coated with a thermion radiation matter, and an anode disposed in a negative glow domain formed between the anode and the hot cathode in the discharge container. In the discharge lamp, the outer diameter D (mm) of the discharge container is selected to satisfy the relation3 W.sub.L <D<10 W.sub.Lwhere W.sub.L the electric power consumption (W) of the discharge lamp when the length L (mm) of the discharge container lies within the range of L=25 to 100 mm.

Abstract: An inverter-type fluorescent lamp ballast is powered from the power line by way of a common and either of two (or more) different power leads. When powering the ballast by way of the common and the first one of these two power leads, the power provided to the fluorescent lamp load is relatively high; when powering the ballast by way of the common and the second one of these two power leads, the power provided to the fluorescent lamp load is relatively low. The ballast itself is a self-oscillating half-bridge inverter loaded by way of a series-tuned high-Q LC circuit connected across its output. A pair of fluorescent lamps is series-connected across the tank-capacitor of the LC circuit. The inverter has two bipolar transistors, each driven by an associated saturable current transformer that provides for a transistor ON-time dependent upon the magnitude of an associated bias voltage.

Abstract: To ensure synchronous operation of push-pull connected oscillator transistors (T1, T2), receiving rectified power via a rectifier (GL) from a power network (U), in which the circuit includes an elevated voltage maintenance or step-up converter circuit having a choke (L2), a switching transistor (T3) and a diode - capacitor circuit (D5, C2), the switching transistor (T3) is controlled from the same source of control voltage as the push-pull connected oscillator transistors (T1, T2), for example by coupling the base of the switching transistor (T3) to receive control energy from a feedback coil (RK3) of a feedback transformer (RK1, RK2, RK3) also supplying feedback energy to the push-pull oscillator transistors (T1, T2). The switching transistor (T3) can be controlled by a controllable resistor (R2) connected to its base, which may receive a control voltage through a control amplifier (FIG. 3: RV) representative of voltage levels in the circuit.

Abstract: A fluorescent lamp is connected in parallel with a resonant L-C circuit powered by a series-applied high frequency voltage from a self-oscillating inverter power supply. The frequency of the series-applied voltage is about 33 kHz during the brief initial period before the lamp ignites, but falls to about 30 kHz after the lamp has ignited. As a result, the detuning taking place in the L-C resonant circuit due to changing parallel-loading is compensated-for by correspondingly changing the frequency of the series-applied voltage. This detuning effect is particularly pronounced in situations where there is a large magnitude-ratio between the lamp's ignition voltage and its operating voltage.

Abstract: An electronic capacitive ballast circuit for operating a DC discharge lamp, such as a negative glow lamp. The circuit includes a rectifier bridge intercoupling a ballast capacitor and the electrodes of the discharge lamp. The rectifier bridge is separated into two halves allowing the discharge current to flow to opposite ends of the filament of the lamp during alternating half-cycles so that the filament (i.e., cathode) is operated in a double hot spot regime. As a result, lamp maintenance and performance are improved.

Abstract: A circuit for cutting a "notch" in an alternating current supply waveform with the minimization of dissipated power comprising a pair of GTO's so poled to conduct current therethrough and also through a pair of power consuming diodes when the switches are "on" during alternate half cycles, the switches being turned "off" at the start of the "notches", and the current is resumed thereafter by a pair of oppositely poled SCR's which are turned "on" and which bypass power diodes so as to conserve power.

Abstract: Disclosed is a novel lamp-lighting device, comprising a full-wave rectifier composed partially or entirely of thyristor(s), said full-wave rectifier having both an input terminal connected with an ac source and an output terminal connected with a lamp; a smoothing means connected in parallel with the lamp; means to detect a voltage across the lamp that exceeds a prescribed level; and means to control the conduction angle of the thyristor(s) dependently on the magnitude of the voltage, said controlling means being operable in association with said detecting means.

Abstract: Disclosed is a novel lamp-lighting device, comprising a full-wave rectifier having both an input terminal connected with an ac source and an output terminal connected with a lamp, a smoothing means connected in parallel with the lamp, means to detect a voltage across the lamp that exceeds a prescribed level, means to switch the operation of said rectifier to half-wave rectification mode, and means to connect said switching means with said detecting means.

Abstract: An electronic ballast circuit is provided for starting, operating and controlling the brightness of one or more fluorescent lamps. The brightness of the lamps is controlled over the full range of brightness from zero to full-rated power. The circuit power factor is controllable, and is preferably operated at a relatively high leading power factor. The circuit includes a capacitive ballast working in conjunction with a gapped transformer so as to provide the high leading power factor while, at the same time, maintaining stable and uniform brightness of the lamps. A power field effect transistor is utilized to function as a current stabilizer in conjunction with the capacitive ballast and gapped transformer. The system incorporates a dimming control circuit for increasing and decreasing the brightness of the lamps.

Abstract: The discharge lamp energizing arrangement of this invention comprises a starter and a generator adapted to maintain a discharge current in the lamp. The generator includes a first circuit arranged to couple in series a D.C. voltage source, a first switch and a second switch. When the first switch is closed the second is open and vice versa. A second circuit arranged to couple an inductance and the lamp in series is connected in parallel with the second switch. The switches are operated by a control means which combines signals received from an oscillator and a comparator so as to regulate the current flow in the lamp. The generator appears as a source of stabilized current for any load which is applied thereto and may just as well be employed for a lighting fixture as for energizing the luminous points of a matrix display board.

Abstract: A self-oscillating inverter-type fluorescent lamp ballast has two modes of operation: (a) a first mode in which the inversion frequency is about 70 kHz and is resonant with a first tuned circuit by which power is supplied to the cathodes of the fluorescent lamp; and (b) a second mode in which the inversion frequency is about 30 kHz and is resonant with a second tuned circuit by which main lamp power is supplied. When the ballast is initially powered-up, it starts operation in its first mode, thereby providing cathode heating power without yet providing main lamp power. About one second later, after the cathodes have reached full incandescence, the inverter automatically changes into its second mode, thereby providing main lamp power while at the same time removing cathode heating power. If for some reason the lamp were not to ignite within about 10 milli-seconds, the inverter reverts back into its first mode; thereafter cycling between its two modes until the lamp does ignite.

Abstract: Appliances such as fluorescent lamps and low-voltage DC motors can be operated from household AC without a transformer by employing a current-limiting circuit which is compact, lightweight, reliable, draws less energy, and has fewer power consuming components than do prior devices for driving those applicances. The current-limiting circuit has 4 rectifiers in a bridge circuit and a current-limiting capacitor which should be selected to match the load, a larger capacitor being necessary to supply a larger current. When used to drive a discharge lamp, the current-limiting circuit should also contain an inductive coil in series with the current-limiting capacitor. Otherwise there may be undue flicker. The inductive coil and capacitor together improve the power factor and therefore reduce the current drawn from the line without reducing the lamp output.

Abstract: A fail safe feature for long life reduced voltage lamps including diodes id disclosed. As known, a low wattage lamp may designed for longer life by using a lower root mean square design voltage. The root means square voltage of the alternating source current may be lowered by including a rectifying element, and a fuse may be included in series with the lamp to safely interrupt the circuit. By further including a one-way shunt oriented oppositely to the rectifier, in parallel with the lamp, and intermediate the rectifier and fuse, on failure of rectifier, unrectified current blows the fuse. If the rectifying diode fails, substantially all of the current is shunted to the fuse during the failed half of the current cycle, thereby blowing the fuse, and safely failing the lamp.

Abstract: A discharge lamp energizing arrangement comprises a starter and a generator adapted to maintain a discharge current in the lamp. The generator includes a first circuit arranged to couple in series a D.C. voltage source, a first switch and a second switch. When the first switch is closed the second is open and vice versa. A second circuit, arranged to couple an inductance and the lamp in series, is connected in parallel with the second switch. The switches are operated by a first control means which employs the signals received from an oscillator. The starter includes a third switch connected in parallel with the lamp terminals. The third switch is operated by a second control means itself operated by the first control means. When the energizing arrangement is turned on the third switch is closed and it subsequently reopens on the first occasion that the first switch passes from the closed to the open state.

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: There is disclosed a device and process for starting up a fluorescent discharge lamp in which a high-frequency pulse is generated having narrow voltage peaks above the voltage required to start electric discharge and broad valleys, applied to the elements of the lamp to effect start up of fluorescence and, after start-up, the voltage automatically goes back to maintenance voltage having broad peaks at the maintenance voltage and relatively narrow valleys. The automatic cutback is effected by the load introduced by the electric discharge and the feedback from the emitter of the transistor used to generate the pulse. A capacitor is serially-connected in the lamp circuit to inhibit the flow of DC current therein.

Abstract: A system and associated method for operating a gas discharge lamp so as to provide a positive voltage-current characteristic. An AC or DC source is used to provide electron heating, without in itself providing ionization, of the lamp gas. Superimposed on this signal is a pulsed source of power having an average output power substantially less than the AC or DC source power for providing ionization of the lamp gas.

Abstract: A circuit arrangement for A.C. operation of gas discharge lamps comprises a full-wave rectifier (1) connected to an alternating voltage source. The direct voltage is supplied to a combinatorial circuit part (3 to 8) in the form of a direct voltage converter, to which is connected a bridge circuit (9) which comprises four thyristors. The transverse branch of the bridge circuit includes the lamp (5). The full-wave rectifier (1) is followed by a smoothing capacitor (2) and an electronic switching element (14) is connected parallel to the bridge circuit (9). The switching element is switched to the conducting state in the vicinity of the zero passages of the input alternating voltage. As a result shortcircuits in the bridge circuit are avoided.

Abstract: A converter of electric power at a first value of voltage and frequency produces a voltage at a second value and at a higher value of frequency by means of an inverter oscillator circuit having two serially connected transistors. An output power transformer is coupled to the transistors for receiving current excitation from alternate ones of the transistors during alternate half-cycles of the output voltage. Incoming voltage is converted by a diode bridge circuit to a DC voltage which drives the transistors. Serially connected capacitors bypass the bridge circuit to couple high frequency current from a primary winding of the transformer through the transistors. Additional windings of the transformer are coupled in the base-emitter circuit of each transistor for inducing states of saturation during conduction phases of each transistor so as to minimize power dissipation within each of the transistors.

Abstract: An improved power supply system of smaller size and lower cost than prior art supplies is described for starting and maintaining the running of a deuterium arc lamp at a constant current level; by use of switching circuitry with solid-state components the necessity of transformers, relays and timing circuits has been obviated with a resultant major reduction in size, cost and cooling requirements of the supply; an improved starting sequence lengthens lamp cathode life.

Abstract: A load is provided, at all times when in operation, with a D.C. voltage having at least a minimum holding magnitude by: providing a source voltage having a peak magnitude greater than the holding magnitude; connecting the source voltage to the load only while the source voltage magnitude is greater than a preselected magnitude; charging from the peak source voltage magnitude an energy storage element while the load is connnected to the source voltage; energizing the load from the charged energy storage element whenever the source voltage magnitude is less than the preselected magnitude; increasing the effective impedance of the load whenever the load is energized by the storage element; and selecting the energy storage element to provide at least the holding voltage to the load during each time interval when the energy storage element is connected to the load.

Abstract: A circuit for operating a discharge lamp at a low frequency AC voltage while repetitively interrupting at a high frequency the voltage component to be applied to the lamp. The circuit includes at least one switching transistor for repetitively interrupting the voltage to be applied to the lamp at the high frequency, for example, 40 KHz so as to allow the use of a light and less bulky inductor as the current limiting conductor to be connected in series with the lamp. A bridge inverter is provided to have at least one pair of switching transistors for alternately reversing a DC voltage to apply the resulting AC voltage to the lamp at the low frequency, for example, 100 Hz low enough to stably operate the lamp without suffering from acoustic resonance. The high frequency component is bypassed through a bypass capacitor connected in parallel with the lamp.

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 touch operated electronic switch for alternating current including a full wave rectifying bridge and two unidirectional current electronic switches one being mounted in parallel with said bridge input and the other being mounted in parallel with said bridge output, each unidirectional current electronic switch being such a silicon controlled rectifier which can be triggered by a touch plate. Said bridge input poles are the two external connections of said A.C. switch. Said unidirectional current electronic switch inserted between said bridge output poles is combined with a low inertia accumulator of electrical energy such as a capacitor mounted in parallel or an inductance mounted in series therewith. A device comprising a neon indicator and its dropping resistor is mounted in parallel with said bridge input so as to faintly light in transparency the touch operated electronic switch for A.C. when it is turned off.

Abstract: A flourescent lamp lighting circuit comprising a rectifying circuit and an oscillatory circuit. The rectifying circuit comprises a rectifier bridge, capacitors and coils to rectify the local alternating power supply to direct power supply and provide rectified electrical power to the oscillatory circuit. The oscillatory circuit comprises two transistors and an L-C circuit which, taken together, form an astable circuit which generates and maintains oscillations. The frequency of the oscillations is determined by the nature of L-C circuits. The ON's and OFF's of the transistors are controlled by induction coils within which currents are induced by the variation of magnetic flux in the inductor coil of the L-C circuit. The high frequency oscillations in the oscillatory circuit induce high frequency electrical signals on a secondary coil which then lights the fluorescent lamp.

Abstract: A variable frequency current control circuit for one or more discharge lamps comprises a push-pull oscillator inverter having an inductance in the DC supply, a non-resonant coupling circuit for coupling the output of the oscillator inverter to the lamp (or lamps) and cycle-by-cycle frequency control of the oscillator in response to a lamp current sensor thereby to automatically control the impedance of the lamp ballast in a sense to regulate the lamp current.

Abstract: A switched AC ballast is operated synchronously with the AC line during normal running of a gas discharge lamp to limit EMI and is locked in a single phase during start-up (i.e. ignition, glow mode and warm-up) to protect the bridge switches from high voltage starting signals. Devices having a high impedance control input, such as FETs, are employed in the switching bridge thus allowing control of the upper devices in the bridge without a floating power supply. A control circuit insures proper operation of the bridge switches during all operating modes of the discharge lamp.

Abstract: An energizing circuit for an incandescent light bulb includes two rectifiers with their outputs connected in parallel across the bulb. One rectifier has a low voltage output to keep the bulb filament warm while the other rectifier, which is energized by closing a switch, has a higher voltage which causes the bulb to emit high intensity light.

Abstract: A ballast circuit for a fluorescent lamp including a rectifier-filter for coupling to an AC power supply to generate a DC voltage, an oscillator circuit coupled to said DC voltage for developing an RF oscillator signal, and switching signal means for developing concurrent oppositely phased switching signals at the frequency of said oscillator signal to drive series connected power transistors. The common output of the power transistors is coupled to energize a fluorescent lamp coil and regenerative feedback means for generating a signal to aid in switching the power transistors.

Abstract: A starter circuit for metal halide discharge lamps in which a diode resistor rectifier network is provided between a conventional ballast and a spiral line generator to superimpose a D.C. voltage on the A.C. ballast voltage thereby to increase the peak instantaneous voltage to the spiral line generators and thus provide a larger breakdown voltage to the discharge lamp.

Abstract: The switches of an AC to AC converter are switched synchronously with the AC supply voltage. EMI conducted to the AC power line is greatly reduced since the rectifier diodes are off at the time of switching, thus avoiding undesirable effects on nearby electrical apparatus. The converter is useful in a ballast for a discharge lamp.

Abstract: A dimming system for fluorescent lamps is disclosed which includes a first switching means connected to said source terminals and to said load terminals for controlling the supply of power to said load terminals, a switch control connected to switching means for modulating said load terminals to modulate the sinusoidal power on a time ratio variable basis in order to supply a variable amount of power to said load terminals; and an inverting reducing transformer connected to said source terminals between said source terminals and a second switch means.

Abstract: A lamp control circuit particularly suited for scale illumination in cathode-ray tube display devices provides stabilized lamp control impervious to temperature fluctuations for either constant or pulsed operating modes.

Abstract: A low-pressure mercury vapor discharge lamp comprises a tubular bulb having an inside diameter of from 22 mm to 35 mm, an electrode-to-electrode distance of from 400 mm to 1,200 mm, and an inner surface coated with a phosphor. A rare gas including Kr and a mercury vapor source are sealed in the bulb, which is energized by an igniting device having a high-frequency power supply connected to a DC power supply for generating a substantially sinusoidal high-frequency output voltage, and a quiescent period generator connected to the high-frequency power supply and including a switch 17 turned on and off at least once during each half cycle to provide a quiescent period and thereby produce a substantially square wave high-frequency output voltage having rise and fall times of 2 .mu.s or less.

Abstract: An electronic transformer system for illuminating neon lamps includes a counterphase oscillator coupled to a leakage reactance power transference transformer. The power transference transformer has a secondary wound on a multiple section bobbin in which adjacent sections are separated from each other by a dielectric material. The leakage reactance power transference transformer has a feedback winding which is coupled in series to the primary winding of a pulse generator base driving transformer. The pulse generator base driving transformer in turn provides periodic pulses to the counterphase oscillator to reverse current flow in the primary of the leakage reactance power transference transformer. The electronic transformer system may be powered by commercial alternating current through a full wave rectifier, or by a direct current power supply.

Abstract: The present invention provides a device for regulating an ac current circuit using a magnetic relay which is suitable for use in an incandescent lamp circuit or electric motor circuit to eliminate or reduce inrush-current. The present device comprises connecting power switch, diodes, series resistance and relay such that, after closing the power switch, an ac current first flows to a load through the series resistance for a brief time, then to the load through the contacts of the relay after a lapse of the brief time by bypassing the series resistance.

Abstract: Various circuit embodiments for reducing the electromagnetic interference (EMI) typically created by a ballast circuit for an improved lighting unit is disclosed. The EMI reducing circuit adapts the operation of the source of the EMI of the ballast circuit to the conductive states of the rectifier means of the improved lighting unit.

Abstract: An electrical control circuit includes a first energy storage means adapted to store electrical energy in response to a potential source of a first polarity relative to a reference point in said circuit, thereby providing a first voltage of a first magnitude; a second energy storage means adapted to store electrical energy, without affecting said first energy storage means, in response to a potential source of a second polarity relative to said reference point, thereby providing a second voltage of a second magnitude; and means for electrically connecting said first and second energy storage means so as to provide an output voltage related to the sum of said first and second magnitudes. Four embodiments are presented with two embodiments arranged so that substantial voltage is supplied to a load only when said first and second energy storage means are connected by an electrical connecting means.

Abstract: A D.C. to A.C. inverter using switching transistors driving a multiple-core transformer which includes a high-permeability saturable core upon which both the primary and secondary windings are wound and one or more lower permeability non-saturating cores upon which the primary and/or secondary windings are wound to provide additional self-inductance. The inverter switching transistors drive the two halves of the transformer's center-tapped primary winding on alternate half-cycles under the control of a feedback winding which is wound on the saturable core. A non-saturating core about which the primary winding is wound, and a capacitor connected in parallel with both halves of the primary winding, protects the switching transistors against transients, prevents the saturating core from going into hard saturation, and efficiently transfers energy stored in the leakage inductance of the primary winding from half-cycle to half-cycle.

Abstract: An electronic ballast for a discharge lamp (8) for restricting and stabilizing the lamps current. The ballast comprises a high frequency oscillator for connection to a D.C. supply which consists of two transistors (1,2) connected in series, with a base drive transformer (3) coupled between them to bring the transistors (1,2) into alternating phase operation. A resonance circuit connected in series with the primary winding (4) of the transformer (3), comprises an inductor (7), resonance capacitors (10 and 11) and a capacitor (9) coupled in parallel with the lamp (8). The lamp (8) is, in turn, connected in series with the resonance circuit. In addition, a filter capacitor (c) having a high charging ability is coupled between the terminals of the D.C. supply. The resonance capacitors (10 and 11) are connected in series between the terminals of the D.C.

Abstract: There is disclosed an operating circuit for an electric discharge lamp in which a first DC operating circuit for starting an electric discharge lamp, a second DC operating circuit for making the electric discharge lamp operative by a voltage near a rated lamp voltage and by a current near a rated lamp current, and a third DC operating circuit for supplying a relatively large current to the electric discharge lamp immediately after the electric discharge lamp is started and for stabilizing the lamp luminous flux in a short time, are connected in parallel. A switching circuit for cutting off the first DC operating circuit after the electric discharge lamp is started is provided at the output terminal of the first DC operating circuit. In addition, reverse current preventing circuits for preventing the currents from reversely flowing from the operating circuits at higher voltages are provided at the output terminals of the second and third DC operating circuits.

Abstract: An arrangement for starting and supplying a discharge lamp (14) equipped with preheatable electrodes (15, 16). An electric coil (13) is arranged in series with the lamp and a capacitor (17) is arranged in parallel with the lamp. A voltage of a high frequency is first applied between the ends (A, B) of the series arrangement formed by the coil (13) and the lamp (14) whereafter approximately 1 second later said frequency is reduced until a series resonant condition is obtained and thereafter still further reduced to the operating frequency of the lamp. This starts the lamp (14) with the electrodes preheated to a sufficient extent.

Abstract: A laser apparatus using a DC-DC converter type pulse power source generates a pulse laser output of a high peak value by utilizing the negative resistance characteristic of a laser discharge tube. The peak value, pulse width, period of the pulse output are adjustable. The apparatus is capable of producing a continuously oscillating laser light; capable of operating always with approximately maximum efficiency for any value of the laser output. The power source device for the laser apparatus permits adjustment of the pulse width and period of the pulse laser output without any adverse effect on the efficiency of the laser apparatus.

Abstract: A drive circuit is disclosed which includes a converter that provides current pulses that charge a capacitive electroluminescent lamp to produce light and a switching circuit that switches a predetermined number of successive current pulses at high frequency for progressively charging the electroluminescent lamp. The switching circuit also reverses the polarity of the electroluminescent lamp at low frequency when the electroluminescent lamp discharges at the end of a predetermined number of successive current pulses and before the electroluminescent lamp charges again by current pulses produced by the converter. The switching circuit is connected to and is responsive to signals provided by the timepiece frequency divider circuit and the converter is connected to the timepiece battery for stepping up the battery voltage to provide for the charging current pulses. The EL lamp is used as its own storage capacitor and receives substantially all of the energy provided by the converter.

Abstract: A gas discharge lamp control circuit for an inductive ballast includes anti-parallel connected controlled rectifiers connected in series with the a.c. source and the ballast and anti-parallel connected controlled rectifiers which are connected in series with a current limiting and energy diversion capacitor and in shunt with the ballast. The controlled rectifiers of the series and shunt switching assemblies are controlled so that, in any given half wave, the related controlled rectifier of the shunt switching means turns on to discharge a capacitor into the normally conducting controlled rectifier of the series switching means to produce a notch in the voltage wave form applied to the inductive ballast. The capacitor acts as a current limiting impedance and acts to permit reversal of the voltage during the notch interval in the input voltage to the ballast, thereby to increase the RMS content of the voltage wave form.

Abstract: A heat-sensitive variable-resistance insert device for use with a light bulb and socket including: a thin, heat-sensitive variable-resistance wafer and a perimetrical insulation member surrounding the edge of the wafer and electrically insulating it from the wall of the socket. The wafer has a contact area on one side for engaging the central contact of the socket and on the other side thereof for engaging the central contact of the light bulb, and an adhesive paste on that other side within the perimetrical member for adhering the device to the base of a light bulb.

Abstract: Ballast apparatus operates a HID lamp at high frequency and high power factor. Series-connected current-limiting input inductor and input capacitor connect across apparatus input and are tuned off resonance to pass predetermined lagging current. An additional input capacitor is connected across input terminals to that input power factor approaches unity. Full-wave diode bridge has input connected across series-connected input capacitor and filter capacitor connects across bridge rectifier output. During normal operation, the filter capacitor develops a DC potential which is current limited by series-connected inductor and capacitor. Inverter has input connected across filter capacitor and inverter an output that drives the HID lamp through a high-voltage generating and variable impedance resonant circuit.

Abstract: A frequency stabilized automatic gain controlled ballast system (10) which is coupled to a power source (12) in order to operate at least one of a pair of gas discharge tubes (40 and 40'). Each of the gas discharge tubes (40, 40') include respective filaments (42, 44 and 42', 44'). A frequency control circuit (11) is coupled to the power source (12) and includes a frequency control transformer (43) and a frequency control capacitor (50) for establishing a constant oscillation signal at a predetermined frequency. A switching network (13) is connected to the frequency control circuit (11) for establishing a pulsating current responsive to the constant oscillation signal of predetermined frequency. Induction circuitry (15) is coupled to the switching network (13) and the frequency control circuit (11) and includes an inverter transformer (78) as well as coupling capacitors (86 and 88) for generating a voltage across the gas discharge tubes (40 and 40').