Abstract: The invention relates to a capacitive coupling-type arc-extinguishing circuit and an apparatus. The capacitive coupling-type arc-extinguishing circuit includes a thyristor which is connected to two ends of a mechanical switch in parallel, where a driving signal for driving the thyristor to switch on is transferred from a main loop of the thyristor to a control electrode of the thyristor by using a capacitor; and a driving signal loop of the control electrode of thyristor is connected to at least an electronic switch. The capacitive coupling-type arc-extinguishing circuit and the apparatus have the advantages of the good arc-extinguishing effect, and high reliability. The apparatus includes a control circuit connected with the electronic switch of capacitive coupling-type arc-extinguishing circuit, have the advantage of short conduction time of the thyristor.

Abstract: A voltage rectifier circuit having a storage element and a switching stage that is switchable to enable the storage element to capture a peak voltage of an alternating power source. The switching stage includes transistors arranged in a back-to-back configuration. In one example, the storage element is a capacitor and the transistors are PNP bipolar junction transistors. The configuration of the circuit enables reduced loading on the power source, as well as reduced sensitivity to temperature.

Abstract: In accordance with embodiments of the present disclosure, a system and method for providing compatibility between a load having a reactive impedance during steady-state operation and a secondary winding of an electronic transformer driven by a leading-edge dimmer may include a first circuit and a second circuit. The first circuit may cause the load to have a substantially non-reactive impedance when the first circuit is enabled. The second circuit may enable the first circuit to cause the load to have the substantially non-reactive impedance during a duration of time following start-up of the electronic transformer and disable the first circuit after the duration such that the load has the reactive impedance during steady-state operation of the load.

Abstract: An induction heating system includes an induction heating coil operable to inductively heat a load with a magnetic field, a detector for detecting a current feedback signal corresponding to a current flowing through the induction heating coil, and a controller for detecting a switching transient in the current feedback signal and determining a resonant frequency of the system based on a characteristic of the switching transient.

Abstract: A current ripple canceling light-emitting diode (LED) driver is disclosed. The input current source contains a current ripple. The LED load is connected to the drain of a power switch. The source of the power switch is connected to a current sensing resistor. The gate of the power switch is connected to the output of an operational amplifier. The operational amplifier compares the voltage signal across the current sensing resistor with a dynamic reference voltage. The dynamic reference voltage is adjusted according to the gate or drain voltage of the power switch. The LED load current is controlled to be a nearly no ripple DC current.

Abstract: A Light Emitting Diode (LED) driver circuit for driving an LED string has a switch-mode power supply coupled to the LED string. A control circuit is provided and has a first terminal coupled to a pulse width modulated input and a second terminal coupled to the switch mode power supply. A disconnect switch is coupled to a third terminal of the control circuit and the LED string.

Abstract: Disclosed is a light source control device including a power conversion unit and a control unit. The power conversion unit includes a transfer capacitor provided between a primary side circuit and a secondary side circuit. The primary side circuit is configured such that a first inductor stores energy when a first switching element is ON. The secondary side circuit is configured such that the second inductor limits a changing speed of the driving current. The power conversion unit is configured such that the driving current is raised when the first switching element is ON. The control unit turns OFF when the magnitude of the driving current exceeds the first threshold value, and turns ON the first switching element when the magnitude of the driving current falls below the second threshold value smaller than the first threshold value.

Abstract: The present disclosure is directed to an input impedance control circuit. In one embodiment, the automatic input impedance control circuit includes a circuit controller that comprises a module for calculating an impedance and a control logic module, wherein the control logic module provides a current enable signal and a current control output signal, a driver in communication with the circuit controller for receiving the current enable signal and the current control output signal, an input voltage sensing circuit in communication with the module for calculating the impedance and the control logic module and an input current sensing circuit in communication with the module for calculating the impedance.

Abstract: The present invention relates to a LED device with shared voltage-limiting unit and individual voltage-equalizing resistance, wherein two ends of a LED set constituted by a plurality of same-polarity series LEDs are in parallel connected with a shared voltage-limiting unit, and two ends of individual LED are respectively in parallel connected with an voltage-equalizing resistance for providing an overvoltage protection to the LEDs.

Abstract: An LED lighting device is provided with output impedance control to stabilize an optical output across a wide current range. A switching power supply generates the output current, with switching control circuitry to determine switching frequency and an ON period for an associated switch, and to turn on/off the switch according to the determined frequency and ON period. An impedance element is coupled across output terminals for the lighting device, with an impedance value set so that a load current is larger than a current flowing to the impedance element at maximum on-duty of the switch and a current flowing to the impedance element is larger than the load current at minimum on-duty. The impedance element may be a variable impedance element, wherein an impedance control circuit adjusts the variable impedance such that an impedance value for minimum on-duty of the switch is smaller than that for a maximum on-duty.

Abstract: An LED device with voltage-limiting unit and voltage-equalizing and current-limiting resistances includes an LED connected in parallel with a voltage-limiting unit, and a current-limiting resistance connected in series between the LED and the voltage-limiting unit. Two ends of each LED are connected in parallel with a voltage-equalizing resistance for forming a light-emitting unit, so that a light-emitting unit set can be structured through connecting two or more than two of the mentioned light-emitting units in series or in series-parallel in the same polarity. With the two ends of each LED being connected in parallel with the voltage-equalizing resistance, the end voltage of each light-emitting unit can be evenly stabilized; and the current-limiting resistance connected in series between the connection joints of the LED and the voltage-limiting unit for limiting the shunt current passing through the voltage-limiting unit.

Abstract: A measured voltage drop across a power-line transistor is used as a sensing element to measure the current and detect an over-current condition for an LED backlight system. An over-current or short condition is detected when the measured voltage drop exceeds a threshold. Accurate detection of the over-current condition is achieved by calibrating the RDS-ON (i.e., internal resistance between drain and source, when transistor is on) of the power-line transistor. In one embodiment, the calibration of RDS-ON is performed by ramping down the threshold from an initial value and using the tripped threshold to determine the actual value for RDS-ON. In another embodiment, the calibration of RDS-ON is performed by using two thresholds, a first threshold to calibrate RDS-ON and a second threshold to detect the over-current condition.

Abstract: A dimmable LED power supply circuit arrangement is disclosed. The circuit arrangement includes a flyback converter coupled between an input for receiving a rectified alternating line voltage and an output providing power for at least one LED device. The flyback converter includes a transformer and a semiconductor switch for switching a primary current of the transformer. A current sensing unit provides a current sense signal dependent on the primary current. A control unit controls the switching operation of the semiconductor switch dependent on the rectified alternating line voltage and the current sense signal such that the flyback converter operates in a quasi-resonant mode of operation, whereby the current sense signal is compared with a time-varying reference signal representing the rectified alternating line voltage and whereby a switch-off time of the semiconductor switch is determined dependent on the comparison.

Abstract: Provided is a circuit for detecting a filament of a fluorescent lamp, wherein a first end of a first filament is connected to a second end of the first filament via an oscillation circuit, and the first end of the first filament is connected to an output of an inverter; a first end of a second filament is connected to a second end of the second filament via an oscillation circuit, wherein the first end of the second filament is connected to an internal ground; the second end of the second filament is connected to a power source, and a voltage at the second end of the second filament is used for controlling ON and OFF of an MOSFET, wherein a source of the MOSFET is connected to the internal ground.

Abstract: Ballasts and LED drivers are presented for powering at least one light source, in which a shunt circuit provides a high impedance to allow operation of the light source when the AC input power exceeds a power threshold value, and provides a low impedance when the AC input power is below the power threshold value to prevent an output power stage from providing power to the light source.

Abstract: A circuit arrangement for operating discharge lamps is provided with an input, to which an AC system voltage from a power supply system can be connected, an output, to which at least one discharge lamp can be connected, a backup capacitance, which is arranged between the input and the output, and a switch, which is in a charging current path of the backup capacitance. The circuit arrangement may include a driver configured to clock the switch for a predetermined period of time when the circuit arrangement is switched on for periodically interrupting the charging current path of the backup capacitance.

Abstract: Exemplary embodiments provide an apparatus, system and method for power conversion to provide power to solid state lighting, and which may be coupled to a first switch, such as a dimmer switch. An exemplary system comprises: a switching power supply; solid state lighting; a first adaptive interface circuit to provide a resistive impedance to the first switch and conduct current from the first switch in a default mode; and a second adaptive interface circuit to create a resonant process. An exemplary apparatus comprises: a switching power supply; and an adaptive interface circuit comprising a resistive impedance coupled in series to a reactive impedance to conduct current from the first switch in a first current path in a default mode, and further comprising a second switch coupled to the reactive impedance to conduct current from the first switch in a second current path, with the adaptive interface circuit further damping oscillation when the first switch turns on.

Abstract: A novel LED driver circuit, including: a current regulation circuit, having a first end and a second end, wherein a first current is flowing into the second end, and a voltage difference between the first end and the second end is generated in response to the first current; a transistor, coupled with the first end and second end of the current regulation circuit; a bias network, having a first end and a second end, the second end being coupled with the transistor; and a LED module, having at least two connection nodes, wherein the connection node at one end of the LED module is coupled to a line voltage, the connection node at the other end of the LED module is coupled to the transistor, and one of the at least two connection nodes is coupled with the first end of the bias network.

Abstract: A DC/AC converter includes a resonant circuit having a first capacitor connected to at least one of a primary winding and a secondary winding of a transformer and an output end connected to a load, the resonant circuit receiving an alternating signal having a predetermined frequency and amplitude to pass a current, a variable impedance element connected in parallel with a part of the output end of the resonant circuit, the variable impedance element changing the impedance value thereof according to a current passing through the load, and a controller to control the current passing through the load to a predetermined value by changing the resonant frequency of the resonant circuit according to the changed impedance value of the variable impedance element.

Abstract: Provision of a light emitting device having functionality for restoring to normal even if a low-voltage error occurs, by temporarily applying a reverse current to a low-voltage error light emitting element using a direction inverting circuit, and repairing portions in which impedance has fallen by applying the current.

Abstract: A current-limiting protection circuit of remotely controlled ceiling fan-lamp is disclosed. The current-limiting protection circuit includes a microcontroller unit for detecting rectangular wave signal reflective of the power used by a lamp load. The rectangular wave signal is compared with nominal value. In the case that the positive bandwidth of the rectangular wave signal is larger than the nominal value, it is indicated that the lamp load is in an overloaded state. Under such circumstance, the microcontroller unit controls a lamp load driving unit to change driving manner and lower the power used by the lamp load to a value within the nominal range.

Abstract: The present invention relates to a light emitting diode with enhanced luminance and light emitting performance due to increase in efficiency of current diffusion into an ITO layer, and a method of fabricating the light emitting diode. According to the present invention, there is manufactured at least one light emitting cell including an N-type semiconductor layer, an active layer and a P-type semiconductor layer on a substrate. The method of the present invention comprises the steps of (a) forming at least one light emitting cell with an ITO layer formed on a top surface of the P-type semiconductor layer; (b) forming a contact groove for wiring connection in the ITO layer through dry etching; and (c) filling the contact groove with a contact connection portion made of a conductive material for the wiring connection.

Abstract: A circuit to control an AC lamp current provided by an input AC voltage supply to a cold-cathode fluorescent lamp (CCFL). The circuit includes a capacitor connected in series between the AC voltage supply and one terminal of the CCFL, the capacitor biasing the CCFL with the AC lamp current; a switch having first, second, and control terminals, the first terminal being connected to the CCFL and the second terminal being connected to the other side of the supply; a diode connected in parallel to the switch; and a resistor connected in parallel to the diode, wherein the AC lamp current is controlled by controlling the switch to add and remove resistance in series with the CCFL.

Abstract: An electronic ballast has control circuitry to provide a pre-heating signal to the filaments of a gas discharge lamp for a predetermined length of time before the lamp is ignited and, further, cease providing the pre-heating signal after the lamp has been ignited.

Abstract: A current sensing circuit for sensing the current provided to LEDs by a constant current power source includes a resistive shunt in series with the load and a current mirror having a first leg connected to a first terminal of the resistive shunt and a second leg connected to a second terminal of the resistive shunt. Both legs of the current mirror are also connected to ground. The first leg provides a reference signal to the second leg, and the second leg uses the reference signal and a voltage at the second terminal of the resistive shunt to provide a ground referenced output signal indicative of the current provided to the LEDs.

Abstract: The present invention relates to a harmonic compensation circuit for compensating at least the third harmonic in the input current (Imains) drawn by an LED light source (1) from a mains voltage supply (2), comprising: a signal input (21, 22) for receiving a first input signal proportional to the input voltage (Vin) of said LED light source (1) and a second input signal (Vsh) proportional to the LED current (ILED) of said LED light source (1), a signal output (25) for outputting a compensation current (Icomp), a processing unit (24a, 24b) for comparing said second input signal (Vsh) to a reference signal (VRb, VR7) and for generating said compensation current (Icomp) based on said comparison, the sum of said compensation current (Icomp) and said LED current (ILED) being proportional to the input voltage (Vin) of said LED light source (1) and said compensation current (Icomp) being provided for minimizing at least the third harmonic in the input current (Imains) drawn by said LED light source (1) from said main

Abstract: Method for setting an electronic ballast, with which an electric lamp is operated which comprises programming first settings of at least one operational parameter of at least one first lamp type into the electronic ballast, setting and operating an electric lamp, which is connected to the electronic ballast, with the programmed first settings as long as a normal operating mode of the electronic ballast is set, changing the first settings of the operational parameters during a secondary operating mode of the electronic ballast, the secondary operating mode of the electronic ballast being set when the electronic ballast identifies a value for the resistance of a lamp filament and/or a substitute load of the electric lamp connected to the electronic ballast which is untypical in comparison with the normal operating mode, the change to the first settings being carried out depending on the identified untypical value for the corresponding resistance.

Abstract: The present invention relates to a method, system and current limiting circuit configured to limit the excess output current passing through a load, said current limiting circuit comprising a resistor connected in series with said load and in parallel with a switch, which is initially turned OFF, wherein said switch is turned ON, thereby shorting said resistor, when the output voltage applied to said load is decreased by a predetermined level.

Abstract: A current sensing circuit for sensing the current provided to LEDs by a constant current power source includes a resistive shunt in series with the load and a current mirror having a first leg connected to a first terminal of the resistive shunt and a second leg connected to a second terminal of the resistive shunt. Both legs of the current mirror are also connected to ground. The first leg provides a reference signal to the second leg, and the second log uses the reference signal and a voltage at the second terminal of the resistive shunt to provide a ground referenced output signal indicative of the current provided to the LEDs.

Abstract: The present invention relates to a light emitting diode with enhanced luminance and light emitting performance due to increase in efficiency of current diffusion into an ITO layer, and a method of fabricating the light emitting diode. According to the present invention, there is manufactured at least one light emitting cell including an N-type semiconductor layer, an active layer and a P-type semiconductor layer on a substrate. The method of the present invention comprises the steps of (a) forming at least one light emitting cell with an ITO layer formed on a top surface of the P-type semiconductor layer; (b) forming a contact groove for wiring connection in the ITO layer through dry etching; and (c) filling the contact groove with a contact connection portion made of a conductive material for the wiring connection.

Abstract: A structural configuration of a failsafe OLED chain with multiple OLED lighting components in series connection is described. During the manufacture of the lighting component a weak spot is specifically installed at an appropriate location of the structure in the form of a break-through layer, which in the event of a failure of the lighting component breaks down and bypasses the component with a bypass layer.

Abstract: A discharge lamp lighting apparatus includes: an inverter circuit including a switch circuit and a high-voltage transformer; a step-up circuit connected at the input stage of the inverter circuit; a control circuit to output a switch circuit controlling signal and a step-up circuit controlling signal; an on-off switching circuit connected at a input voltage line; and a switch signal buffering circuit connected between the control circuit and the switch circuit and adapted to relay the switch circuit controlling signal. A drive voltage is applied to the control circuit without going through the on-off switching circuit, and a drive voltage is applied to the switch signal buffering circuit via the on-off switching circuit. With such a structure, an excess rush current is inhibited from flowing into the discharge lamp thereby preventing its electrode wear and therefore increasing the product life of a lamp and enhancing reliability while achieving cost reduction and downsizing.

Abstract: A system includes a switching transistor that provides a current source to a load when activated by an input voltage and at least one Zener diode connected in parallel with the load that acts as a shunt regulator. The system may be especially suited for matching the controlled luminance of light emitting diodes to the controlled luminance of incandescent lighting. The system may also be useful for displays where a single master voltage regulator switch or controller controls the different types of lighting. The system may be packaged in a chip scale package for compactness, reduced weight, cost effectiveness, and higher efficiency and reliability.

Abstract: An article carrier assembly for attachment to a vehicle roof panel comprises two siderails and at least one cross-rail releasably stowed on one of the siderails. Attachment of the cross-rail to the siderails is carried out with the use of latching mechanisms. The mechanism is composed of a stanchion mounted on the cross-rail, with a lever pivotally placed therein, and of a lock plate assembly slidably attached to the siderail. For deployment of the assembly, the stanchion is put on the lock plate assembly which becomes engaged therewith upon turning the lever. The structure of the mechanism contributes to preventing the roof panel from being damaged upon the deployment.

Abstract: A device comprising energy saving circuitry incorporated within lighting systems of the type utilizing discharge lamps, wherein the circuitry includes at least one transformer having a primary and secondary windings oppositely wound to establish different fields of polarity. The primary winding is connectable across a supply voltage and the secondary winding is connected in series with the discharge lamps lead. A switching assembly is associated with each of the one or more transformers and is operative in a first position to connect the primary winding across the supply voltage, wherein a voltage of an opposite polarity is induced across the secondary winding. In a second operative position the one or more switch assemblies serve to disconnect the primary winding from across the supply voltage and to shunt the primary winding, so that voltage across the secondary winding is zero (v).

Abstract: The present invention relates to a surge current limiting circuit of a filament lamp, meant to be connected in series between the filament and a switch that supplies an a.c. voltage, including at least one controllable active element, for limiting the current to a predetermined threshold value.

Abstract: The invention relates to a method for adjusting at least one operating parameter of an operating unit (EVG), equipped with a microcontroller (MC), for electric lamps. The adjusting method according to the invention includes a closed loop which carries out a successive correction of at least one drive parameter, stored in the microcontroller (MC), for the voltage transformer of the operating unit (EVG). There is no need for an adjusting resistor.

Abstract: An electronic ballast circuit for driving a gas discharge lamp from a mains voltage signal supply includes a ballast bridge unit having upper and lower signal lines. A capacitive divider is disposed across the bridge. The capacitive divider comprises at least two capacitors coupled in series at a common reference voltage signal terminal. The bridge unit also includes two diodes coupled in series at a rectifier common terminal, wherein each of the diodes is respectively coupled to one of the signal lines of the bridge unit. The bridge unit further includes an input converter bridge and an output converter bridge each having at least two switches coupled in series at input and output common terminals, respectively.

Abstract: A piezoelectric illumination control circuit for a microscope comprising a tunable frequency source of alternating current, a piezoelectric crystal having an impedance dependent on operating frequency, driven by the tunable frequency source of alternating current, and a load driven by the piezoelectric crystal. A second embodiment comprises a piezoelectric illumination control circuit for a microscope, comprising a constant frequency source of alternating current, a piezoelectric crystal coupled to a tunable dummy reactive load for the purpose of varying the impedance of the crystal and dummy load, the piezoelectric crystal driven by the constant frequency source of alternating current, and a load driven by the piezoelectric crystal.

Abstract: A lighting circuit for a discharge lamp capable of improving the lighting performance of a discharge lamp with a simple circuit structure to thereby prevent a lighting failure at the end of the lifetime of the discharge lamp. The lighting circuit 1 comprises a DC power supply circuit 2, DC-AC conversion means 3 for converting a DC voltage output from the DC power supply circuit 2 to an AC voltage and supplying the AC voltage to the discharge lamp 5, a circuit element 6 (a switch element or a current limiting element) for blocking or limiting a current counter-flowing to the DC power supply circuit 2 from the DC-AC conversion means 3, and an inductive load 4 connected in series to the discharge lamp 5. A series circuit of a Zener diode 7 and a passive element 8 (a capacitor or a resistor) is provided in parallel to the circuit element 6, so that when the Zener diode 7 conducts, a rise in an auxiliary voltage for reignition is suppressed.

Abstract: The invention relates to a circuit arrangement for operating a high-pressure discharge lamp. A buffer capacitor is shunted by a branch which comprises a series circuit of a second capactor and a unidirectional element for blocking a current with which the second capacitor charges the buffer capacitor Re-ignition after a zero crossing of the low-frequency alternating current has a comparatively high amplitude so that the lamp re-ignites in a reliable manner.

Abstract: A retrofit lamp having light emissive diodes, and more particularly, to a retrofittable lamp configured as a standard incandescent lamp which can be used effectively in illuminated signs, such as an exit sign, for operation on each cycle of A/C voltage applied. The newly designed solid-state lamp features a base that can be rotated, approximately 160 degrees, to allow for the optimal positioning of the LED array to maximize the light intensity directed toward the illuminated area.

Abstract: A protection circuit for non-isolated ballasts that drive gas discharge lamps to prevent shock hazards. The device acts to prevent excessive leakage currents from flowing between the ballast and ground by introducing a higher common mode impedance path in the circuit. A two stage common mode filter assembly has a first common mode inductor series connected to a second common mode inductor. A first capacitor is connected across the common mode inductors. A second capacitor is connected between the junction of the first capacitor, the first inductor, the second inductor and ground. The circuit protects by reducing high frequency leakage currents.

Abstract: A lighting circuit, which is lit with a voltage with a square wave, has a DC booster circuit, a bridge type DC-AC converter and an inductor provided at the subsequent stage of the DC-AC converter. A metal halide lamp is connected in series to the inductor. Another inductor and a capacitor are provided between the DC booster circuit and the DC-AC converter. A series circuit of a resistor and a diode is connected in parallel to the second inductor. This structure generates a resonance voltage having a high peak value to compensate for a re-ignition voltage of a discharge lamp which is produced when the polarity of the square-wave voltage is switched, thereby preventing the lighting failure of the discharge lamp immediately after the lighting starts.

Abstract: This is an electron emission with a semiconductor substrate having a p-type semiconductor layer whose impurity concentration falls within a concentration range for causing an avalanche breakdown in a least a portion of a surface of the semiconductor layer. A Schottky electrode is connected to the semiconductor layer. There are a means for applying a reverse bias voltage between the Schottky electrode and the p-type semiconductor layer to cause the Schotty electrode to emit electrons, and a lead electrode, formed at a proper position, for externally guiding the emitted electrons. At least a portion of the Schottky electrode is formed of a thin film of a material selected from metals of Group 1A, Group 2A, Group 3A, and lanthanoids, metal silicides of Group 1A, Group 2A, Group Group 3A, and lanthanoids, and metal borides of Group 1A, Group 2A, Group 3A, and lanthanoids, and metal carbides of Group 4A. A film thickness of the Schotty electrode is set to be not more than 100 .ANG..

Abstract: A fluorescent lamp ignition circuit of the type including a DC voltage stabilizer to process input voltage into a constant voltage by dropping or boosting, an inductance filter to receive output power supply from the DC voltage stabilizer and to remove surge from it, an oscillator having a transformer, which receives output power supply from the inductance filter and then provides a sin-wave output for igniting a fluorescent lamp, and a feedback circuit connected between the oscillator and the fluorescent lamp to provide a feedback signal to the DC voltage stabilizer, wherein the feedback circuit includes two shunt resistors, which connect the mid-point of the secondary side of the transformer of the oscillator to earth, and two diodes respectively connected between the shunt resistors and the DC voltage stabilizer to form a double-feedback loop.

Abstract: A circuit arrangement for igniting and operating a discharge lamp (La), provided withinput terminals (K1,K2) for connection to a DC voltage source,a commutator (COM) coupled to the input terminals and provided with terminals (K3,K4) for connecting the discharge lamp (La), for cornmutating a current through the discharge lamp (La),a branch A which is conducting in both directions at least for alternating current, of which branch a first end is connected to an input terminal (K2) and a further end is connected to the commutator (COM), and which branch comprises an inductive element L shunted by a branch B which comprises a unidirectional element (D),a branch C which connects a further input terminal to the commutator (COM), andan ignition circuit (S) for igniting the discharge lamp. According to the invention, the unidirectional element (D)is so included in the branch B that the branch B conducts a current at least immediately after ignition of the discharge lamp (La).

Abstract: A relatively high efficiency, relatively light weight, relatively small electronic ballast or AC power controller for use in aircraft and elsewhere for controlling a fluorescent lamp load or other load includes an EMI filter, a multi-purpose transformer, a power conversion stage and a control circuitry stage. The ballast or controller operates to increase or decrease the voltage of the incoming sine wave AC voltage through a charging path for an energy storage inductor choke cooperating with an energy storage capacitor wherein the charging path for the capacitor is different from the discharge path of the capacitor to isolate the load from the charging of the capacitor and thus to provide an output to the load which is independent of the charging path and which is out of phase with the incoming waveform.

Abstract: A control circuit for reducing current flow through the UV light bulb of a water purification unit when water is not flowing through the unit. In a first embodiment, the control circuit includes an RC shunt selectively connected in parallel with the UV bulb, thereby selectively adding a positive impedance in parallel with the negative impedance of the bulb. In a second embodiment, the control circuit includes an impedance selectively connected in series with the bulb ballast. In either embodiment, the impedance circuit is actuated in response to a water flow switch. When water is flowing through the unit, the impedance is removed so that full current is delivered to the bulb enhancing UV intensity. When water is not flowing through the unit, the impedance is added so that current flow is reduced.

Abstract: A control circuit is disclosed that can be used to control the light intensity of a fluorescent lamp. A first embodiment of the control circuit includes one variable inductor and a plurality of fixed inductors. A switch is used to connect one of the inductors to the fluorescent lamp in parallel. The intensity of the light output from the lamp is varied either by adjusting the inductance of the variable inductor, or by switching between the fixed inductors. A second embodiment uses a variable capacitor in place of the variable inductor and uses fixed capacitors in place of the fixed inductors.