Abstract: A two-lamp rapid start fluorescent lamp circuit in which the lamps are ignited in sequence and then operated in series. The circuit being energized from a low voltage a.c. source through the use of a substantially conventional ballast which utilizes a transformer having a primary winding and a secondary winding connected in autotransformer relationship. The circuit includes a disconnect socket and a conventional two contact socket for mounting each lamp. The disconnect sockets in one circuit are arranged in one example to open the connections between the filament windings and a filament of each lamp. In another circuit one disconnect socket is arranged to open a connection to a filament winding and the other disconnect socket is arranged to open one of the connections to the line.

Abstract: A rapid start circuit for starting and step dimming a fluorescent lamp includes a voltage step up auto transformer and lamp filaments for starting, ballast and a pair of capacitors having different values variously connected in series with the lamp and ballast by a rotary switch; first in parallel, then individually and then in series to achieve a progressively stepped dimming of the lamp. A second form of the invention includes a first capacitor in series with the lamp and ballast for reducing the maximum light output of the lamp and a plurality of capacitors each having a different value selectively connected in parallel with the first capacitor by a slide switch to selectively dim the lamp; and a resistor in series with the first capacitor to diminish arcing and noise when switching. Both forms of the invention include a pair of secondary windings for maintaining filament voltage.

Abstract: A lighting circuit for an electric discharge lamp according to the present invention is constructed in such a way that a switching device is provided at an output terminal of a high frequency inverter which produces a substantially sinusoidal output voltage, and that, by controlling this switching device, an output to the low pressure electric discharge lamp is stopped at the rising part of the abovementioned output voltage in its half cycle, while the output is supplied to the low pressure electric discharge lamp at the voltage level in the vicinity of the maximum instantaneous value thereof. By use of the high frequency inverter of a smaller capacity and less radio noise than those in the conventional device, the operating efficiency of the low pressure electric discharge lamp can be increased.

Abstract: The above and other objects, advantages and capabilities are achieved in one aspect of this invention by a drive scheme for a plurality, that is, for N, where N-2, flourescent lamps. The drive circuit comprises (N+1) pairs of output terminals, each comprising associated first and second individual terminals. An output transformer is coupled at one end to the (0,1).sup.1 terminal and at another end to the (0,1).sup.N+1 terminal. N impedance elements, typically capacitors, are coupled across associated pairs of lamp filaments in a fashion whereby each impedance element is coupled at one end to the second terminal of one pair and at another end to the second terminal of the succeeding pair. To wit: The first impedance element is coupled between the second terminal of the first pair, and the N.sup.th element is coupled between the second terminal of the N.sup.th pair and the second terminal of the (N+1).sup.th pair.

Abstract: A mode detector for microwave oven magnetrons is disclosed including means for sensing interruption of anode current and providing a discrete indication thereof. An alternative embodiment discloses means to count the number of such interruptions. A method of detecting incipient failure of the magnetron is disclosed wherein the discrete output of a mode detector is observed and a determination is made that an incipient failure exists when the mode detector output frequency exceeds a predetermined limit.

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').

Abstract: Disclosed is a discharge lamp lighting device which comprises a series closed-loop circuit including an AC power supply, a ballast having an inductance, and a discharge lamp, and a switch circuit in parallel to the discharge lamp. The switch circuit is turned on when the voltage across the discharge lamp is reduced to zero, and then turned off when the current flowing in the switch reaches a predetermined value. The switch circuit thus repeats its on-off operation every half cycle of the voltage across the discharge lamp. The electromagnetic energy is stored in the inductance of the ballast when the switch circuit is on, and the stored electromagnetic energy is superimposed on the source voltage and applied to the discharge lamp when the switch circuit is turned off, thus reigniting the discharge lamp every half cycle. This makes it possible to light directly a discharge lamp having a lamp voltage approximate to the source voltage.

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: A high frequency oscillator-inverter ballast-ignition system for a discharge lamp includes a leakage reactance transformer that forms a part of the oscillator-inverter and also couples same to the discharge lamp. An impedance element electrically couples the primary and secondary windings of the transformer in additive phase to provide more reliable lamp ignition over a wider range of voltage and temperature than was heretofore possible. The preheat time period of the lamp cathodes can be better controlled by a proper choice of the transformer heater winding turns.

Abstract: A method of controlling the power output of a magnetron tube, and an electric power supply for supplying power to the tube. According to the method, power is continuously supplied to the magnetron heater. At the same time, a voltage is continuously applied across the anode and the cathode of the tube. This voltage across the anode and the cathode varies in cycles between a first value, which is substantially at or below the threshold voltage of the magnetron tube, and a second value, which is above the threshold voltage. The average magnetron power output is determined by the proportion of each cycle during which the voltage across the anode and the cathode is above the threshold voltage.

Abstract: In conventional fluorescent signaling devices the filament is fed with 50 Hz alternating current and the multiplex frequency of the signal ranges similarly in the area of 50 Hz, so that brightness variations occur with the difference in frequencies. A simple means for avoiding disturbing effect is the circuit of the present invention which divides the heating alternating current voltage into several stages and connects the negative terminal of the supply voltage of the fluorescent signaling device to one of the intermediate stages of the heating alternating current voltage depending on the signaling point that at the instant concerned happens to be lighted.

Abstract: A lightweight, transistorized, inverter circuit is particularly adapted for starting and operating a screw-in compact fluorescent lamp intended for incandescent lamp replacement. Household-type AC is converted to DC with one terminal connected to the center tap of a transformer primary through a choke which constitutes a high impedance at the operating frequency. A tuned circuit capacitor is connected across the transformer primary and a current-limiting capacitor and the lamp to be operated are connected in series across the transformer primary. A pair of transistors are connected in push-pull arrangement between the end portions of the transformer primary and the other terminal of the DC source, with the base electrodes of the transistors connected to the transformer secondary winding so that the push-pull connected transistors oscillate at the tuned circuit resonant frequency which is determined by the inductance of the transformer primary winding and the total capacitance of the connected capacitor means.

Abstract: A method and circuit for operating an incandescent lamp are disclosed in which the operating voltage applied to the lamp alternates in a regular and abrupt manner between forward and reverse polarities. The magnitude of the voltage is substantially the same for the two polarities and, therefore, the luminosity of the lamp is substantially constant. However, lamp life is increased as compared to standard DC operation since the alternating polarity of the operating voltage reduces the rate at which the lamp fails due to lamp filament breakage.

Abstract: A circuit for starting and operating fluorescent lamps from an a-c power source, comprising reactive ballast means connected to ballast the lamps and having a non-linear characteristic for producing harmonics of the power source frequency, and a capacitor and a cathode heating transformer connected in series and connected to receive power from said ballast means and resonant in a frequency range including two or more of said harmonics. A switch may be connected in series with the capacitor and cathode heating transformer for opening the cathode heating circuit when the lamps are operating, to conserve electrical energy.

Abstract: An energy conserving lighting system is provided wherein a plurality of fluorescent lamps are powered by a poorly regulated voltage source power supply which provides a decreasing supply voltage with increasing arc current so as to generally match the volt-ampere characteristics of the lamps. A transistor ballast and control circuit connected in the arc current path controls the arc current, and hence the light output, in accordance with the total ambient light, i.e., the light produced by the lamps together with whatever further light is produced by other sources such as daylight. In another embodiment, a transistor ballast is utilized in combination with an inductive ballast. The transistor ballast provides current control over a wide dynamic range up to a design current maximum at which maximum the transistor is saturated and the inductive ballast takes over the current limiting function.

Abstract: An apparatus for a gaseous discharge lamp includes a power controlling device for converting an AC voltage into a phase control output, a high frequency generating device for converting the output of the high frequency generating device into an high frequency output and a discharge lamp which is lighted by the output of the high frequency generating device and whose filament is heated. The high frequency generating device includes a DC power source for supplying a DC voltage to the power controlling device whenever the power controlling device remains to generate the phase control output. The output of the DC power source heats the filament of the discharge lamp for a period during which no phase control output is produced.

Abstract: Microwave oven with a self-regulating circuit operated from a low voltage a.c. source based upon a substantially constant current transformer and condenser series combination and having a return path for current on alternate half cycles. For defrosting food the magnetron is operated at partial power which is achieved by decreasing the voltage applied to the magnetron. This is done either by increasing the capacitive reactance in series with the secondary of the transformer or by decreasing the secondary voltage. Switching problems are solved by providing the arrangement of the invention at the grounded end of the transformer secondary. The self-regulating circuit is required to be of the type which has one end of the secondary winding grounded.

Abstract: An improved drive scheme for a pair of push-pull inverter transistors in an electronic ballast circuit. The inverter output is coupled through a series resonant circuit comprising a capacitor and the primary winding of an output transformer. The resonant circuit is coupled to the inverter output through an additional winding on the primary of an interstage so that a component of the loop current is fed back to the bases of the push-pull transistors, thereby compensating for phase errors in the drive signal applied at the inverter input.

Abstract: A dimmer circuit for an inverter-driven electronic ballast system. The ballast includes an output transformer having a primary winding coupled to the inverter output and a secondary winding adapted to be coupled to a lamp filament winding for supplying power to the filament. An interstage transformer has a primary winding adapted to be coupled to a lamp filament and a secondary winding coupled to an inverter input for applying a feedback signal derived from the filament current at that input. The dimmer circuit is in the form of a feedback loop that includes a winding on the primary of the output transformer, a winding on the primary of the interstage transformer, and a variable impedance coupling those windings. Varying the impedance necessarily varies the total feedback loop impedance and therefore the amount of feedback applied at the inverter output and, inversely, the power supplied to the lamp filament.

Abstract: A fluorescent lighting device which includes a preheating type fluorescent discharge tube and as the ballast thereof an incandescent bulb. The fluorescent lighting device is ignited by the use of a pulse transformer and a neon tube. A semiconductor element may be used in place of the neon tube.

Abstract: A method for starting and operating a preheat type fluorescent lamp includes a source of alternating current, a fluorescent lamp having a low impedance starting mode wherein current passes through one or more starting filaments and a high impedance operating mode wherein current passes through the length of the lamp, a starting switch directing current through the starting filaments in the lamp starting mode, and an inductor ballast having a magnetically permeable core operating in a saturated condition when the lamp is in the low impedance starting mode and in a non-saturated condition when the lamp is in the high impedance operating mode.

Abstract: In a cathode-ray tube provided with a direct-heating type cathode, a transformer through which the cathode is heated is disposed within the bulb of the cathode-ray tube. This improvement eliminates the instability of heating due to the contact resistance caused between the base pins of the cathode-ray tube to which the terminals of the cathode are connected and the socket pins to which the base pins are fitted.

Abstract: A low pressure gas discharge lamp is provided with a pair of high power incandescent electrodes to increase output illumination at the lamp ends. In an alternate construction, the electrodes are of high power, low emissivity and are electrically connected to a second pair of high emissivity electrodes which provide the means for enabling the mercury discharge. With this second construction, the low emissivity electrodes can act as ballast for the circuit.

Abstract: A simplified power source for fluorescent lamps is characterized as that the filaments of the fluorescent lamps are connected in series with the primary winding of a transformer, an oscillator circuit and the power source so that the oscillating current will exert high voltage across the primary winding to start and drive the fluorescent lamps and when the fluorescent lamps are removed from their sockets, the oscillator circuit will be opened to prevent from occurring high tension for safety measure.

Abstract: A circuit for starting and operating a low-voltage fluorescent lamp from a 120 volt AC supply. The circuit includes a choke type ballast connected in series with the lamp and inductively coupled to a pulse train generator comprising an RC energy storage circuit connected across the line and a voltage sensitive transistorized relaxation oscillator having a divider network for sensing lamp voltage. In a preferred embodiment the circuit is employed in a preheat mode of operation in combination with an electronic starter circuit comprising a PTC resistor, silicon diode and SCR series connected across the lamp.

Abstract: Described is a circuit to invert DC to AC for the operation of electroluminescent lamps. A primary winding of a transformer is in series with a power source and the input or output of the switching device. The output of the switching device is connected back to the power source. The secondary winding of the transformer is in series with an electroluminescent lamp and the controller side of the switching device. The secondary winding doubles as both the output to the electroluminescent lamp and the feedback winding to the controller side of the switching device. The electroluminescent lamp doubles both as the load and limiting impedance to the controller side of the switching device. Also described is a unique device for dimming the electroluminescent lamp.

Abstract: A power supply for controlling the duty-cycle of a microwave oven magnetron and the like power-energizing load, includes a parallel combination of a non-linear resistance element, such as a varistor and the like, and a gateable semiconductor switching device, such as a triac and the like, in series with a power supply voltage-doubler diode, connected in parallel across the magnetron. The flow of current through the magnetron is substantially reduced or prevented when the semiconductor switching device is gated to an "off" condition and is substantially enabled to a normal current flow value when the semiconductor switching device is gated to an "on" condition, typically by high frequency squarewaves provided at the gate electrode.

Abstract: A circuit for controlling power consumption of a load, by controlling the flow of current thereto, utilizes at least one parallel combination of non-linear resistance elements, such as a varistor and the like, and a gateable semiconductor switching device, such as a triac and the like, to substantially reduce or prevent current flow when the semiconductor switching device is gated to an "off" condition and to enable normal current flow to a load when the semiconductor switching device is gated to an "on" condition. Embodiments of the power circuits for control of magnetron power, in a microwave oven, are illustrated.

Abstract: An arrangement for starting and operating a low-pressure mercury vapor discharge lamp provided with preheatable electrodes. The lamp is supplied from a battery via two direct-to-alternating current converters connected between the battery and the lamp. One converter is a voltage-controlled converter which exclusively effects the preheating of the electrodes, whereas the other converter supplies the lamp current only. This arrangement provides reliable ignition and operation of the lamp even in the case of a large variation in the battery voltage.

Abstract: An apparatus for heating the cathode of an electronic power tube, having a supply for delivering a heating current to the cathode, an interrupter circuit for periodically interrupting the flow of heating current to the cathode, and controls for controlling the duration of these periodic interruptions and for regulating the net amount of heating current. To achieve this, the controls include a voltage control that varies in such a way so as to bring the heating current from a value of O to Io (where Io is the correct heating current at which the tube will be in a pre-heated condition) during a first, predetermined time period, and then from a current Io to a current Im (where Im is the optimum value for the heating current when the tube is normally operating), during a second predetermined time period.

Abstract: This invention is a circuit to invert DC to AC for the operation of electroluminescent lamps. A primary winding of a transformer is in series with a power source and the input or output of the switching device. The output of the switching device is connected back to the power source. The secondary winding of the transformer is in series with an electroluminescent lamp and the controller side of the switching device. The secondary winding doubles as both the output to the electroluminescent lamp and the feedback winding to the controller side of the switching device. The electroluminescent lamp doubles both as the load and limiting impedance to the controller side of the switching device.

Abstract: The invention relates to an electric arrangement comprising two series-arranged discharge tubes which are provided with preheatable electrodes and which are stabilized by means of a relatively small ballast. The tubes are shunted by a semi-conductor switching element which operates in the operating condition of the tubes.According to the invention a control circuit of the semi-conductor switching element includes a non-linear circuit element which ensures that the discharge tubes do not ignite before the electrodes are in the warm state.

Abstract: A gas discharge lamp is connected across a step down auto transformer and in series with a solid state switching device and a resistor, and this combination is connected across a rectified AC voltage source. This switching device is controlled by a monostable multivibrator, the input of which is connected to the output of a comparator amplifier sensing the difference between the voltage drop across the above-mentioned resistor and a voltage which may be selected to vary light intensity. A starter aid conductor is placed adjacent the lamp and connected to the grounded side of the voltage source. This results in an efficient, high frequency operation of the lamp wherein the voltage gradient inside the lamp during starting ignition of the lamp is greatly increased to facilitate ignition despite the presence of the step down auto transformer, thereby permitting a decrease in the minimum fly back voltage necessary to start the lamp. As a result, reliability is increased.

Abstract: A voltage multiplier device is disclosed which includes a circuit and a means for coupling the circuit between a television filament transformer and the heater filament leads of a C.R.T. picture tube of a television set. The device is operative to develop a voltage across the two leads of the C.R.T. heater filament that is greater than the voltage developed across the two secondary leads of the transformer.

Abstract: A discharge lamp is ignited in every half cycle in its operating system including a discharge lamp operating circuit provided with a low frequency alternating current power source, a single winding type current limiter. The discharge lamp is connected to the power source through the current limiter and a series circuit including a high voltage output generator is connected in parallel to the discharge lamp. The high voltage output generator operates during the lamp operation for reigniting the discharge lamp. The voltage of the low frequency alternating current power source is set to less than the required reignition voltage of the discharge lamp during its operation, whereby the lamp current stabilizer size is minimized. Further, a filament preheating circuit is arranged to use current derived from the high voltage generator. The filament preheating circuit is combined with this operating circuit and so is a time delay for assuring a stable operation.

Abstract: Electrical power is converted into rectangular waves, which are loosely coupled to a fluorescent lamp. A parallel tank circuit resonant near the fundamental or a harmonic of the square wave frequency is connected between the electrodes of the lamp. The electrodes of the lamp each have a pair of terminals across which an electrical potential is applied to heat the electrodes while starting the lamp. Power is applied across the first and second electrodes while starting the lamp and after starting the lamp. Power is also applied and/or the pair of terminals of the second electrode while starting the lamp and after starting the lamp. The ratio of voltage across the first and second electrodes to the voltage across the pair of terminals is such as to properly preheat the electrodes and prevent arcing between each pair of terminals, and arcing between the first and second electrodes while starting.

Abstract: An electric discharge lamp circuit arrangement wherein rapid starting of the lamp is obtained by charging a ballast impedance capacitance via a unidirectional current conducting path in a sense such as to breakdown a voltage breakdown device in the control electrode lead of a controllable switching device connected with the lamp to provide a current path between the supply terminals comprising, in series, the capacitance, heating means for the lamp main electrodes and the switching device. On breakdown, the switching device temporarily conducts to complete the series path and cause a pulse of current to flow through the heating means, whereafter the capacitor recharges and a further current pulse is produced. The unidirectional current path may extend through the breakdown device or by-pass the breakdown device via a rectifier.

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

Abstract: Direct current ballasting and starting circuitry for efficiently operating a gaseous discharge lamp on direct current. Series-pass switching means in one of a pair of input lines alternatively switches between on and off states to periodically supply pulses of energy from a source of direct current voltage. During steady-state operation, current sensing means limits the maximum current conductable by said switching means such that the output of the circuitry is current regulated. Starting means, in series connection between the filter means and an output terminal, senses the nonionized state of the lamp and provides a voltage pulse of sufficient magnitude and duration to initiate ionization in the lamp. Various forms of control means or drive means for controlling the conductive state of the switching means are disclosed.An A.C. to D.C.

Abstract: A magnetron energizing circuit preferably uses two transformers of the high leakage reactance type having isolated secondaries with an end terminal of each secondary connected to a common point which is at ground potential. The secondaries are connected to series condensers in two loops which provide leading current flowing in the secondaries at all times while both are connected in the circuit to produce saturation in the respective cores of the secondaries whereby to achieve substantially constant current and good regulation for variations in the primary voltage. A single magnetron is served by the circuit and variations in the loading of the magnetron are also compensated for by virtue of the substantially constant current circuit. The secondaries are connected in opposite phase with respect to the respective capacitors which they serve to charge to obtain a full wave doubler operation when the transformers are both in circuit but with low peak current.

Abstract: A radar system having automatic compensation to the heater power applied to the final output tube for changes in the peak tube power output. Substantially constant peak power is attained for radar pulses of varying widths and over a plurality of range scales. A controlled voltage is derived in accordance with the peak of the anode power or current coupled to the final transmitter tube. The control voltage is amplified to operate a free-running bistable multivibrator the output of which is transformer coupled to the heater of the output tube.

Abstract: A series of discrete heating current pulses are passed through a line cathode so as to cause the cathode to emit electrons therefrom. Between each consecutive pair of pulses is a cooling period during which no heating current flows through the cathode. Current is extracted from the cathode during this cooling period. In a preferred embodiment for an image display device, the heating pulse duration is about 10 .mu.sec and the cooling period is about 50.mu.sec. In this scheme, the heating period corresponds roughly to the horizontal retrace time between line times of 50.mu.sec.

Abstract: A magnetron device emits through the filament terminals electromagnetic waves of a broad frequency band which act as noises to other electronic devices. The magnetron device comprises a filament or heater circuit for supplying heater voltage to the filament to emit thermal electrons from the cathode and an anode circuit for applying a required voltage across the filament and anode. The filament circuit is connected to one secondary winding of a power supply transformer and the anode circuit to the other secondary winding thereof. Connected to the anode power supply line is a filter device comprising a capacitor and a choking element having a sufficient inductance to reduce a relatively low frequency of the broad frequency band. This filter device is intended to reduce or suppress a large amount of the noise transmitted to the anode circuit out of a magnetron through filament terminals.

Abstract: A vacuum fluorescent display system for displaying a plurality of illuminable characters includes a plurality of segmented anodes, at least one cathode filament, a plurality of control grids interposed between the anodes and the cathode filament and circuitry for controllably powering the cathode filament and for sequentially driving the control grids whereby selected segments of the anodes are sequentially illuminated and the luminous intensity of the segments of each of the anodes is substantially the same. The cathode filament is controllably powered by removing and applying heating power in response to driven and undriven states respectively of the control grids. By controlling when heating power is applied to the cathode filament the voltage along the cathode filament is the same for each anode when the selected anode segments are sequentially illuminated thereby substantially eliminating variation in luminous intensity.

Abstract: An energizing circuit for gas discharge lamps for room or street lighting or for lights used in document copying machines and the like comprises means for continuously energizing the same at a low non-useful light producing level when such lamps are not needed by a voltage which strikes an arc and maintains a low level of ionization with an infinitesimally small current and very little energy drain. This voltage may be an AC voltage or a DC voltage supplied by a unique circuit including a number of DC voltage sources, rectifiers, voltage adjusting and current-limiting impedances and electronic switches. The lamps are energized by AC or pulsating DC supplied by the aforesaid or other electronic switches operated at a high frequency of at least about 20-30 kilo-Hertz.

Abstract: The magnetron apparatus comprises a magnetron tube and a driving circuit including a transformer having a primary winding, a low voltage secondary winding for energizing the cathode filament of the magnetron tube and a high voltage secondary winding for applying an anode voltage upon the anode electrode of the tube. The high and low secondary windings and the terminals of the cathode filament are contained in a shield casing for preventing leakage of the wave.

Abstract: There is disclosed an oscillator circuit for driving a fluorescent lamp, which comprises a power transistor having an emitter electrode connected to one terminal of a D.C. power source and a collector electrode connected to the other terminal of the D.C. power source through a primary winding of a transformer. A first secondary winding of the transformer is connected at its one end to the other terminal of the D.C. power source and at its other end to a base electrode of the transistor through one of a pair of filaments of the fluorescent lamp. A second secondary winding of the transformer is connected at its one end to the one filament of the fluorescent lamp and at its other end to the other filament of the fluorescent lamp to cause discharge in the fluorescent lamp.

Abstract: A high frequency self-contained emergency lighting fluorescent pack is exteriorally mountable to a fluorescent fixture either in line with a fluorescent lamp having a length shorter than that normally installed in the fluorescent fixture or in a side-by-side relationship near the fluorescent lamp. In either configuration, the emergency lighting fluorescent pack de-energizes all electrical connections when the interconnected fluorescent lamp is not properly in place, and only energizes the electrical connections when the fluorescent lamp is properly installed.The emergency lighting fluorescent pack incorporates a battery pack, a battery charger for maintaining the batteries in the battery pack at full charge, a high frequency emergency power generating inverter module for igniting and maintaining the fluorescent lamp in the illuminated state by energy supplied by the battery pack, and transfer circuitry for causing the energization of the emergency power module by the battery pack when utility AC power fails.

Abstract: High pressure sodium vapor lamps containing sodium or both sodium and mercury are raised in color temperature and improved in color rendition by pulse operation. During the pulse there is considerable enhancement and broadening of the sodium lines at 449, 467, 498 and 568 nm and the development of a continuum from 400 to 450 nms, and also the appearance of visible mercury lines in lamps containing mercury. Optimum results with lamps in size ratings from 50 to 1000 watts are obtained with pulse repetition rates from 500 to 2000 Hz and duty cycles from 10 to 35%. The color temperature may be increased from the common value of 2050.degree. K to 2500.degree. K with reduction in lamp efficacy of only about 20% from conventional 60 Hz operation. Even higher color temperatures may be obtained if further reduction of efficacy is acceptable.

Abstract: Gaseous discharge lamps of high pressure sodium vapor type having an arc tube containing a mixture of sodium vapor and another metal vapor are operated with unidirectional current (DC) pulses in a manner to avoid color separation of the light due to segregation of the atoms of the different metal vapors. The DC pulses are applied to the lamp with repetition rates of from about 50 Hertz to about 23,000 Hertz and a duty cycle of from about 8% to about 80%.