Abstract: The present disclosure provides an inverter module capable of driving two linear compressors through three upper arm elements and three lower arm elements.

Abstract: An arrangement for use in a utility meter includes a transformer, a voltage source, a sensor, and a processor. The transformer includes a primary winding, a first secondary winding, and a second secondary winding. The voltage source is operably connected to generate a voltage signal and to provide the voltage signal to the first secondary winding. The generated voltage signal has a corresponding current formed at least in part by an impedance defined in part by a permeability of the transformer. The sensor is operably connected to generate a permeability signal indicative of the corresponding current. The processor is operably connected to the sensor and is configured to generate a hot socket detection signal responsive to the permeability signal indicating that the permeability of the transformer has fallen below a threshold value.

Abstract: A power supply for a magnetron has a high voltage converter, a microprocessor and a resistor. The high voltage converter comprises an integrated circuit oscillator, switching transistors, an inductance L1, a transformer and a rectifier. A voltage source supplies an augmented DC voltage to the converter. An operational amplifier, arranged as an error signal magnifier with an integrating capacitor and a resistor, compares a control signal from the microprocessor and the resistor and supplies an output signal to the oscillator. The oscillator controls the switching transistors, the output of which is connected to the inductance and the primary winding of the transformer. The secondary winding of the transformer is connected to half bridge diodes and capacitors, which provide DC current from the transformer to the magnetron.

Abstract: A filament preheat module for preheating a filament of a lamp powered by a power circuit including an inverter, the inverter comprising an inductively coupled conductor, an inductively coupled conductor of the filament preheat module magnetically coupled to the inductively coupled conductor of the inverter to power the filament during preheating, and a switching circuit configured to electrically connect the power from the inductively coupled conductor of the filament preheat module to the filament. The switching module is configured to cutoff the power to the filament from the filament preheat module after a predetermined time period during preheating.

Abstract: A driving system and method for color sequential liquid crystal display (LCD) are described. The driving system includes a sensor, scanning modules, switching modules and a control unit. The control unit receives the sensing signal from the sensor and controls the first switching module based on the sensing signal for switching the scanning module to select one of the scanning modes in response to the environment temperature. The control unit adjusts the scanning direction of the liquid crystal display according to the switched scanning mode. The control unit controls the switching module based on the driving mode corresponding to the sensing signal. Further, the switching module switches the gamma voltage-setting module for selecting one of the voltage-setting values in response to the sensing signal and driving the liquid crystal display.

Abstract: The present invention relates to an electronic ballast for discharge lamps (LA) which have preheatable electrodes (E1, E2). The electronic ballast has a measuring apparatus (M), which is designed to measure, during the preheating process, a variable, which is correlated with the electrode temperature increased by the preheating, of at least one of the electrodes (E1, E2) of a connected discharge lamp (LA), and a control apparatus (C), which is designed to match the electrode temperature, during the preheating process, in response to the measurement by adjusting an operational parameter of the electronic ballast. Furthermore, the electronic ballast is designed to detect cross discharges or a sufficient operating temperature of one of the electrodes (E1, E2) and possibly to ignite the discharge.

Abstract: An electronic ballast control apparatus and method for fluorescent lamps includes applying a heating current through the filaments of the lamp, and delaying the application of arc current through the filaments and the gas for a predetermined time. This allows the filaments to heat up to a level capable of sustaining thermionic emission, thereby eliminating sputtering damage upon the application of the arc current.

Abstract: An electronic ballast for a fluorescent lamp includes a delay triggered circuit which, upon expiration of a predetermined period during which the lamp filaments, constituting opposite electrodes of the lamp, are preheated, applies high frequency operating voltage across the opposite electrodes of the lamp beginning with a transition from a condition of no voltage to a condition of full rated voltage which occurs within one cycle of the high frequency voltage. The sharp transition from zero "glow current" to full "arc current" at the end of the preheating period has been found to increase the life of lamps in the number of on-off starts, particularly with respect to lamps of poor quality. The rapid transition is possible because the ballast uses the same inverter and transformer for supplying preheating and operating voltages. The operating voltage is applied between the opposite electrodes of the lamp via an electronic bi-directional switch, controlled by a preheating delay RC timing circuit.

Abstract: A fluorescent lamp lighting control apparatus and method for use in a refrigerator is provided. Here, power is supplied according to opening of a refrigerator door and a fluorescent lamp is preheated for a predetermined time and is turned on by a counter-electromotive force supplied from a stabilizer after being preheated. The fluorescent lamp lighting control apparatus detects whether or not said fluorescent lamp is lit up, and repeats the lighting operation until said fluorescent lamp is lit up when it is detected that said fluorescent lamp is not lit up. Accordingly, the lighting operation of a fluorescent lamp installed in a refrigerator is secured.

Abstract: A circuit arrangement used with electronic ballast equipment has an inverter which supplies a high-frequency half-bridge voltage to at least one load circuit having a lamp throttle, a fluorescent lamp, an ignition capacitor, and a half-bridge capacitor. In order to pre-heat the coils of the fluorescent lamp in a short period of time, a switchable voltage source is activated. This voltage source is connected to the output of the inverter. The outputs of the voltage source are constructed as a pair, to which the electrodes and the fluorescent lamp are connected in parallel. This voltage source includes a transformer having a primary winding coupled to the inverter and is switched between non-conducting and conducting (energized) states by a switching stage. The secondary windings of the transformer are connected in parallel to the electrodes of the fluorescent lamp.

Abstract: A method and apparatus for driving a fluorescent lamp is described wherein the fluorescent lamp is operated in the phanotronic, or hot-cathode, mode. The filament preheat current is decoupled from the arc current through synchronization of the filament voltage and arc voltage waveforms to provide sense windows during which the filament condition may be precisely and accurately determined. Sensing circuits provide correctional feedback to the filament voltage signal to provide optimal filament heating.

Abstract: A ballast arrangement is disclosed for use in powering fluorescent and other gas discharge lamps. The ballast arrangement controls the arc voltage provide by an arc voltage oscillator independent of the filament voltage provided by a filament voltage oscillator. In this manner, safe maintenance condition during fault and interrupt condition are obtained. The full arc voltage is only applied to the lamp when the lamp filaments are warm or after a time period during which they are warmed. The filament pre-warming time reduces sputtering when an excitation or arc voltage in subsequently applied to induce lamp arcing.

Abstract: Method and apparatus for igniting fluorescent lamps at a predetermined temperature of their cathodes. In the present invention, it is the resistance of the cold lamp cathodes that is always measured and ignition occurs as a result of the relationships or conditions of the cold resistance to the hot resistance or the voltage relationship of cold to hot, so that the absolute value has no influence and correct preheating is achieved with all types of lamps.

Abstract: A method is provided in which a relatively cold lamp filament may be turned on for a brief period of time, then turned off, then turned on again, then off again, and this process repeated for successively longer periods of on time, until eventually the filament power is left on continuously. This "pulse starting" may be controlled by a programmable microcontroller in association with a power supply to the lamp filament. The result is a longer lasting lamp filament.

Abstract: An energy efficient and cost effective electronic ballast circuit which lights a fluorescent tube but which avoids excessive voltages or pulsing of the tube. The starter circuit preheats the filaments for a time sufficient to ensure quick ignition upon application of an appropriate voltage, then ceases the flow of current after the tube is lighted to avoid wasting energy.

Abstract: A power supply circuit for driving a magnetron equipped in a microwave oven, provides a stable power to the magnetron by preventing instability of output voltage due to LC resonance between a high voltage condenser (HVC) for driving a secondary winding of a transformer and the magnetron, and by good insulation between the secondary windings of the transformer in a switching mode power supply employing pulse width modulation.

Abstract: A driving circuit for one or more gas discharge lamps (102, 104, 106) having heatable filaments (102A&B, 104A&B, 106A&B) includes: a self-oscillating, series-resonant oscillator (196, 198, 178, 180) for producing a high-frequency output voltage for application to the lamps via an output-coupling transformer (212); a resistive-capacitive divider (190, 192) for starting-up the oscillator after a first delay; a voltage boost IC (144) for causing the oscillator to produce a boosted output voltage when the voltage boost IC is activated and an unboosted output voltage when the voltage boost IC is unactivated; and a resistive-capacitive divider (170, 172) for starting-up the voltage boost IC after a second delay.

Abstract: Circuits for increasing the efficiency of fluorescent tubes by openings one side of all of the filament circuits of the tubes in response to flow of plasma current. The circuits may be employed in conjunction with the circuits of Lucetta U.S. Pat. No. 3,954,316. It should be noted that solid state relays could also be employed so that filament current, although not completely terminated, would be substantially terminated and filament losses would be inconsequential.

Abstract: In an electronic ballast for at least one fluorescent lamp equipped with heatable electrodes, the heatable electrodes must be adequately preheated before the actual ignition of the fluorescent lamp. Given a high-frequency preheating of the heating electrodes that is usually employed and given the utilization of a frequency shift of the high-frequency of the D.C.-A.C. converter, relatively long preheating times on the order of magnitude of >1.2 second result. In order to be able to significantly reduce the preheating tifme below 1 second, it is proposed that a D.C. path be provided wherein the heating electrtodes are connected in series with the secondary winding at the secondary side of a transformer and to connect this D.C. path to the operating D.C. voltage during the preheating phase via controlled switches.

Abstract: In a power-line-operated inverter-type magnetron power supply having a high-Q resonant L-C circuit series-excited by the inverter and parallel-loaded by the magnetron, subject invention provides for cost-effective means to prevent the destructive overload of the inverter and/or the L-C circuit that may occur during the brief period before the magnetron cathode becomes incandescent. In this power supply, the unfiltered pulsed DC output of a full-wave power-line-supplied rectifier means is applied to a pair of inverters: an auxiliary inverter for heating the magnetron cathode, and a main inverter for providing the main magnetron power. The auxiliary inverter starts operating immediately upon application of power from the power line, and therefore immediately starts the process of cathode heating.

Abstract: In a fluorescent lamp, a "soft" start-up circuit initially applies a lamp, or inter-electrode, voltage which is limited to a peak voltage that will not start the lamp prior to heating of the lamp cathode to the proper temperature. The lamp cathode is then heated to the proper start-up temperature after which the lamp voltage is increased to a value well in excess of the ignition voltage required for all lamp types and operating characteristics in initiating lamp operation. The increased lamp voltage is applied in a pulsed manner until the lamp is ignited, whereupon the lamp may be operated at normal lamp current and cathode voltages or the lamp filaments may even be turned off with a consequent savings in input power.

Abstract: A device and process for the generation of ozone using an ozone generator having two electrodes connected across the secondary winding of a high voltage transformer, the primary winding of which is connected to a converter which supplies thereto a square wave current of variable amplitude and variable frequency. A compensation coil is connected across either the primary winding or the secondary winding of the transformer. The ozone generator includes a solid dielectric and a gas path between its two electrodes. The inductance of the compensating choke and the operating frequency of the converter are selected such that the resonance frequency of the resonant circuit formed by the ozone generator and the compensation choke lies below the operating frequency of the converter current supply in any operating condition.

Abstract: A ballast-inverter circuit for a discharge lamp with preheatable electrodes. The lamp is connected to the supply voltage input terminals via a ballast impedance. A triac provides a preheat current path for the lamp electrodes and has a gate electrode connected to an RC timing circuit. A PTC resistor is coupled between one input terminal and the timing circuit to trigger the triac so as to heat up the lamp electrodes and assist the lamp to ignite. The PTC resistor heats up until its resistance is so high that the timing circuit is no longer able to trigger the triac into conduction. The electrode preheat circuit is effectively disconnected from the lamp electrodes when the lamp is in operation.

Abstract: A fluorescent lamp operating device having a power supply, a circuit for converting the output power from the power supply into a high-frequency power, a lighting circuit connected to a secondary side of a transformer of the high-frequency power converter circuit to light a fluorescent lamp, a circuit for preheating the filament of the fluorescent lamp, a switch circuit including diodes and at least one transistor connected in series with the fluorescent lamp in the lighting circuit, and a control circuit for turning off the transistor for a predetermined period when the power supply is turned on thereby turning off the lighting circuit to actuate the preheating circuit during this period. The control circuit turns on the transistor at the end of the predetermined period to thereby actuate the lighting circuit.

Abstract: For the magnetron in a microwave oven, a full-bridge inverter power supply comprises two pairs of switching transistors and is conditionally operable to self-oscillate in either of two modes: a first mode wherein one of the two pairs of switching transistors self-oscillates in manner of a half-bridge inverter and powers the magnetron's thermionic cathode, and a second mode wherein both pairs of transistors self-oscillate in manner of a full-bridge inverter and then provide the magnetron's anode power as well as its cathode heating power. The first mode gets initiated immediately upon applying power to the power supply, but the second mode does not get initiated until about 5 seconds after the initiation of the first mode. That way, the cathode will have become fully thermionic prior to applying anode power to the magnetron.

Abstract: A full-bridge inverter comprises two pairs of switching transistors and is conditionally operable to self-oscillate in either of two modes: a first mode wherein one of the two pairs of switching transistors self-oscillates in manner of a half-bridge inverter and powers a first load, and a second mode wherein both pairs of transistors self-oscillate in manner of a full-bridge inverter and then powers a second load in addition to the first load.Such a dual-mode inverter has utility in situations where a load has to be pre-conditioned with a relatively small amount of conditioning power (such as cathode heating power) before being ready to absorb its main operating power. Typical examples of such loads are magnetrons and fluorescent lamps.

Abstract: With the AC voltage output from an inverter series-driving a high-Q parallel-loaded resonant L-C circuit, and with the parallel-connected load being of a type that needs to be conditioned before it will absorb power (as would be the case with loads such as magnetrons or fluorescent lamps), the inverter and/or the L-C circuit may be destructively overloaded during the time it takes for the load to become conditioned.In a power-line-operated inverter-type power supply with such a high-Q parallel-loaded resonant L-C circuit series-connected across its output, subject invention provides for means to prevent such destructive overload. In this power supply, the unfiltered pulsed DC output of a full-wave power-line-supplied rectifier is applied to a pair of inverters: an auxiliary inverter for pre-conditioning the load, and a main inverter for powering the load.

Abstract: In a power-line-operated inverter-type power supply for the magnetron in a microwave oven, power is provided to the magnetron from the inverter by way of a series-excited resonant LC circuit, the magnetron load being connected in parallel with the tank capacitor of this L-C circuit. This arrangement provides for good matching between the output characteristics of the inverter and the operating characteristics of the magnetron. To prevent potentially destructive overload of the inverter, as may occur if the inverter's output voltage is series-applied to the resonant L-C circuit before the magnetron is ready to absorb power, inverter oscillation is not initiated until after the magnetron cathode has been heated to incandescence.

Abstract: An electrical device for igniting and supplying a low-pressure mercury vapor discharge lamp (11) provided with two preheatable electrodes (12,13). A series arrangement (12, 4, 14, 13) comprising the two lamp electrodes (12, 13), a PTC resistor (14) and a second winding (4) of a transformer fed back negatively with respect to a first winding (3) thereof is connected to a connection point of the first transforming winding. This series arrangement (12, 4, 14, 13) is further connected to a second connection point of the first transformer winding (3). Thus, the electrical device will readily ignite and supply the lamp and will also protect the PTC resistor of the electrical device should the lamp fail to ignite even with lamp electrodes that are uninterrupted.

Abstract: A method and apparatus are provided for operating a fluorescent lamp illumination control sytem which comprises an AC voltage source for supplying power to an electrical load comprising a standard transformer-ballast unit driving a fluorescent lamp or lamps which have externally heated cathodes, and a power controller, which includes a capacitive synchronous switch formed by an electronic switch and shunt capacitor, for controlling the "on" time of the lamp or lamps to thereby vary the luminance output thereof to values less than the nominal rated value. The invention provides heating of the lamp cathodes prior to arc ignition, provides arc ignition at a lower arc current level than that for full-on operation, and provides for subsequently gradually increasing the arc current after the arc is struck to a value providing the desired illumination level.

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

Abstract: A duty cycle power control circuit for a magnetron including a power transformer having a primary winding, a secondary anode winding for supplying anode voltage to the magnetron and a secondary filament winding for energizing the filament of the magnetron. In the illustrative embodiment the power transformer primary winding comprises a main winding and a serially connected standby winding. Duty cycle controlled switching devices are effective in a standby state to connect the main winding in series with the standby winding across an external power supply and are effective in the power on state to disconnect the standby winding and connect the main winding directly across the external power supply.

Abstract: A ballast circuit for starting and operating a preheat type circular fluorescent lamp, which replaces a multiple wattage incandescent lamp in a three-way incandescent lamp socket, so that the fluorescent lamp can be ignited to function at three different operating wattages. A lamination stacked core structure mounts first and second coils. A passive circuit element, such as positive temperature coefficient resistor also known as a thermistor, is connected in the circuit, which includes a three-way incandescent lamp screw base, for current switching functions to achieve the desired ignition and operating currents for the fluorescent lamp at its different operating wattages.

Abstract: An energization arrangement for a discharge lamp includes a DC/AC converter to which a discharge lamp (81) is connected. The lamp is shunted by a relay contact (90) to obtain an electric circuit through which two electrodes (83, 84) of the lamp can be preheated. It is advantageous to insure that the relay contact is closed before a voltage occurs between the electrodes of the lamp. This prevents the lamp from exhibiting a transient flash at too cold electrodes. A timing circuit (40-47) ensures that the relay contact remains closed for about 1 second, after which the lamp ignites with warm electrodes. No electrical losses occur in the relay winding (30) during operation of the lamp.

Abstract: A starter circuit for fluorescent discharge lamps having a high reignition voltage with respect to a peak open circuit voltage wherein a timing and triggering circuit is utilized to delay the application of a the lamp voltage to a starter until the relatively high reignition voltage has passed and a normal lamp operating condition is in effect.

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 starting circuit for gas discharge lamps, such as fluorescent lamps, includes a relay coil controllable switch. A rectifier-multiplier has its input connectable to the alternating-current mains via the controllable switch. A polarity-reversing switch is coupled to an output from the rectifier-multiplier for supplying direct-current to electrodes of at least one gas discharge lamp. Devices responsive to energization of the mains effect reversal of the polarity-reversing switch upon each energization of the mains. A time-delay relay responsive to each energization of the mains effects the closing of the relay coil controllable switch subsequent to each polarity-reversing action of the polarity-reversing switch.

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: 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 voltage supply for an X-ray tube provides both high and low voltages to the tube. A high voltage transformer using split primary and secondary windings is employed. The high voltage is switched on and off by selectively phasing the voltage across the transformer's secondary coils. Low voltage is coupled from one of two primary windings.

Abstract: An apparatus for operating a gaseous discharge lamp comprises a D.C. power source, a transistor inverter which is connected to the D.C. power source through a switch, provided with at least one inverter transistor and generates an output having a prescribed frequency, and a discharge lamp which is energized by an output from the transistor inverter and having a pair of electrodes heated by part of the output. The apparatus further comprises base current control means which holds the base current of the inverter transistor at a level lower than a first level during a prescribed length of time after the close of the switch, and holds the base current at the first level after the prescribed length of time. The discharge lamp has its electrodes preheated, but does not display discharge when the base current has a level lower than the first level, and commences discharge when the base current reaches the first level and thereafter continues discharge.

Abstract: A ballast circuit for controlling the ignition characteristics of a preheat type fluorescent lamp of the type having a transformer with a primary, operating secondary, filament and auxiliary ignition windings, in which there is provided a rectifier having A.C. input terminals, one connected to an end of the operating winding and the other connected to an end of the auxiliary ignition winding by a resistor, and a pair of D.C. output terminals across which is connected a resistive ballast. A starting capacitor is connected to the junction of the resistor and the rectifier A.C. input terminal and applies the auxiliary starting voltage after a time delay. A second capacitor, connected in the lamp running circuit, is charged through a resistor and diode and makes an additional voltage available.

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: A microwave oven control circuit in which the filament of a magnetron supplying microwave energy to the oven is heated to its electron emitting temperature around 1500.degree. C where it emits red spectrum radiation which is sensed by a photoconductive element through the magnetron microwave output structure to produce a control signal actuating the magnetron high voltage supply.

Abstract: In the system disclosed, a transformer connected to an alternating power source establishes a continuous alternating output voltage which is connected directly across a gas discharge lamp to apply the voltage continuously across the lamp. The transformer output voltage is set within a range which includes a condition that causes the lamp to exhibit a positive impedance value when the lamp is discharging. The transformer and the source together exhibit an impedance substantially less than the impedance value of the discharging lamp.

Abstract: A starterless circuit arrangement for the ignition and the operation of one or a number of series connected, low voltage fluorescent lamps which are connected with a stray field transformer coupled with a voltage source. The stray field transformer produces the no-load voltage needed for firing the lamps and possesses heating coils which are connected with the electrodes of the lamps. A cold conductor having markedly positive resistance characteristic is connected in parallel with at least part of the secondary winding of the stray field transformer in order to maintain the voltage applied to the lamp(s) at a value beneath the firing or ignition voltage for such length of time until the electrodes of the lamps are pre-heated.