Abstract: A constant voltage device include a diode; a switch including one terminal connected to a ground potential and another terminal connected both to an anode terminal of the diode and to a drain of a PMOS transistor having a source applied with a power source voltage; a voltage generation circuit configured to generate a voltage of a predetermined magnitude; and a differential amplifier that includes a non-inverting input terminal to which both a cathode terminal of the diode and an output terminal of the voltage generation circuit are connected, and that is configured to change a supply route of a reference voltage applied to the non-inverting input terminal according to a state of the switch. The voltage generation circuit is configured to employ an output voltage based on the reference voltage and amplified by the differential amplifier to generate the reference voltage.

Abstract: An anti-flicker and anti-glow switchable load apparatus to be installed in the light socket of a commonly powered electronic switching device, such as a motion activated light switch. An energy efficient light bulb or lamp, such as a cathode fluorescent lamp or light emitting diode is then electrically connected to the apparatus. A first embodiment of the present invention includes a switchable light source, a switchable load, a controller, and a voltage sensor. When the present invention in the first embodiment detects a higher voltage, thus indicating the lamp has been switched from the “off” state to the on state, the switchable load is disconnected, and the current is re-routed to pass through the energy efficient lamp.

Abstract: A system and method for fast, automatic balancing of an AC bridge utilizes a two-stage process. During the first stage, the phase of the bridge voltage is matched, while during the second stage, the amplitude is minimized. The voltage matching process is based on halving the range of measured voltage amplitudes at each step, using two samples to identify the next half-range, resulting in an n-step recursive algorithm with “n” defining the resolution of the process. As such, the phase-matching process requires only three samples per step, and only four steps for 1° resolution. Consequently, the computational power needed to carry out the two-stage process is minimal, requiring only comparison of the three sampled voltages, thereby resulting in a balancing process that is performed fast and efficiently.

Abstract: An anti-flicker and anti-glow switchable load apparatus to be installed in the light socket of a commonly powered electronic switching device, such as a motion activated light switch. An energy efficient light bulb or lamp, such as a cathode fluorescent lamp or light emitting diode is then screwed into the apparatus. A first embodiment of the present invention includes a switchable light source, a switchable load, a controller, and a voltage sensor. When the present invention in the first embodiment detects a higher voltage, thus indicating the lamp has been switched from the “off” state to the on state, the switchable load is disconnected, and the current is re-routed to pass through the energy efficient lamp.

Abstract: A pulse-excited mercury-free lamp system, and method of sustaining the emission of light emission from such a lamp, is provided. The system includes a light-transmissive envelope having an inner surface and a phosphor layer coated thereon. A discharge-sustaining gaseous mixture of a noble gas, at a low pressure, and a metal halide, is retained inside the light-transmissive envelope. An electrical system provides a plurality of pulses to the discharge-sustaining gaseous mixture, resulting in a discharge, which causes the lamp system to emit light. The emission of light is maintained by turning the discharge on during a pulse width of each pulse in the plurality of pulses and by turning the discharge off during a remainder of each period in the plurality of pulses. Particularly in systems where the metal halide is indium-based, this maintains an efficient emission of light without the use of mercury.

Abstract: A passive anti-arcing protection components for electronic ballasts of fluorescent lamps. This protection component is a bridge-rectifier-resistor-capacitor network, containing at least a diode, a resistor, and a capacitor. The component's circuitry is electrically connected to the ballast at the lamp side, acting as a low-resistance redirection path for any sudden change in energy. When an arcing condition is about to occur, this protection circuitry absorbs the spark energy, ceasing the arcing condition.

Abstract: Configurations for an LED driver are disclosed. The proposed LED driver receives an input voltage, drives an LED and includes a compensation capacitor set including a first and a second capacitors connected to each other in series, wherein the first capacitor is electrically connected to the LED, the second capacitor is grounded, the compensation capacitor set provides a compensation voltage to the LED such that the LED is conductible when an instantaneous voltage value of the input voltage is lower than an LED conduction voltage.

Abstract: A power management circuit comprising a power-on signal input, an output terminal a control unit, a switching unit, and a discharge unit. The control unit configured to selectively turn on the switching unit to output a power-on signal to a display module and selectively turn off the switching unit to cut off an electrical connection between the power-on signal input and the output terminal. The discharge unit configured to discharge residual electrical charges in the display module when the switching unit is turned off.

Abstract: An electronic device including a light emitting element. A capacitor is coupled to the light emitting element. A measurement circuit measures a change amount in charge of the capacitor. A control circuit controls a light emission amount of the light emitting element in accordance with a difference of the change amount in the charge and a reference value.

Abstract: A dynamic damper in a lighting driving circuit for limiting an inrush current includes a damper circuit and a timing circuit comprising capacitor. The damper circuit is connected to the timing circuit. When an input voltage is provided to the dynamic damper, the capacitor begins to be charged and the capacitance-voltage of the capacitor rises. The damper circuit enters to a first working state and generates a dynamic damper resistor value. When the capacitance-voltage of the capacitor is greater than a first threshold voltage, the damper circuit enters to a second working state and the dynamic damper resistor value begins to decrease. When the capacitance-voltage of the capacitor is greater than a second threshold voltage, the damper circuit enters to a short-circuit state, and the dynamic damper resistor value decreases to zero to facilitate the normal work of the power source converter.

Abstract: According to one embodiment, a luminaire includes a housing, a cable run, and a noise filter circuit. A lighting-circuit-integrated lamp is arranged in the housing. The cable run is configured to supply an external power to the lighting-circuit-integrated lamp. The noise filter circuit is provided in the cable run and reduces a noise terminal voltage.

Abstract: A power management circuit comprising a power-on signal input, an output terminal a control unit, a switching unit, and a discharge unit. The control unit configured to selectively turn on the switching unit to output a power-on signal to a display module and selectively turn off the switching unit to cut off an electrical connection between the power-on signal input and the output terminal. The discharge unit configured to discharge residual electrical charges in the display module when the switching unit is turned off.

Abstract: A driving circuit for driving a light-emitting diode (LED) light source includes a buck-boost converter and a controller. The buck-boost converter receives an input voltage and an input current and powers the LED light source, and comprises a switch controlled by a driving signal. The controller receives a first signal indicating a current through the LED light source, and generates the driving signal based on the first signal to control the switch and to adjust the current through the LED light source. The buck-boost converter further comprises a current sensor which provides a second signal indicating an instant current flowing through the buck-boost converter, wherein the first signal is derived from the second signal, and wherein a reference ground of the controller is different from a ground of the driving circuit.

Abstract: A driving circuit for driving a load is provided. The driving circuit includes a control module providing a control signal to adjust a load current flowing through the load; and a voltage clamping module providing a power voltage to the control module.

Abstract: An electronic device including a light emitting element. A capacitor is coupled to the light emitting element. A measurement circuit measures a change amount in charge of the capacitor. A control circuit controls a light emission amount of the light emitting element in accordance with a difference of the change amount in the charge and a reference value.

Abstract: Electronic ballasts, driver apparatus, and methods are provided in which a heating current is generated by the driver to power a resistive heating element of an insulation detector associated with a recessed can fixture using a regulated current source/sink circuit.

Abstract: The present disclosure discloses a multi-mode dimming circuit configurable to operate in a first dimming mode, a second dimming mode and a third dimming mode. The present disclosure also discloses separate dimming circuits for respectively realize the three dimming modes. In one embodiment the multi-mode dimming circuit may comprise a first input terminal, a second input terminal, a third input terminal, an output terminal, a resistive device, an oscillation circuit and a pulse width modulation (PWM) circuit. Users may flexibly configure the multi-mode dimming circuit to operate in one of the three different dimming modes by varying the external devices and/or signals coupled to each of the first, second and third input terminals.

Abstract: A series circuit comprising a diode and a resistance is connected in parallel to a filament, and a series circuit comprising a diode and a resistance is connected in parallel to a filament. The filaments are preheated by a preheating current supplied from secondary windings of a preheating transformer, via preheating capacitors. Detection circuits detect DC voltage components of the preheating capacitors. Comparators compare the DC voltage components of the preheating capacitors with a reference voltage. The comparators cause a control circuit to protect the inverter circuit if an abnormality of the filaments is detected.

Abstract: A method of controlling a Fluorescent Lamp (CFL) is disclosed, which enables the lamp to be dimmed during a quick-start mode in which the lamp current may be boosted. The method involves determining a boost value and a dimming value, and controlling the lamp power in dependence on the boost and dimming values. A dimming threshold may be set, below which (i.e. at dimmer output light levels) the boost function is disabled. Hysteresis may be included in the control, in order to avoid hopping between modes. A controller for use with a fluorescent lamp which is adapted to operate according to such a method and a fluorescent lamp using such a controller are also disclosed.

Abstract: An incandescent lamp includes a lamp voltage conversion circuit within the lamp and connected to a lamp terminal, where the voltage conversion circuit converts a first line voltage at the lamp terminal to a second RMS load voltage usable by a light emitting element of the lamp. The voltage conversion circuit includes a triac phase-controlled dimming circuit, which in turn includes a voltage controlled resistor that varies a resistance in the phase-controlled dimming circuit as the first voltage varies so as to maintain the second voltage substantially constant. The voltage conversion circuit may be an integrated circuit that is in the lamp base and connected between the lamp terminal and the light emitting element.

Abstract: The present invention is a lighting device for an electronic or electromechanical apparatus such as a timepiece of the wristwatch type. The invention includes a device displaying time-related or other information, this lighting device including a light source for lighting the display device. The lighting device is characterized in that the light source is also able to measure the intensity of the ambient light. The invention also concerns a method for controlling the lighting of an apparatus of the aforementioned type.

Abstract: The invention relates to ballast for a discharge lamp (16), comprising a direct-current supply phase (2), semiconductor switches (10, 11), operated at a high-frequency clock frequency for modifying the direction of current through the discharge lamp (16), an ignition transformer (15), which can be supplied with the direct current of the direct-current supply phase (2) via a series capacitor (14) and a choke inductance (17) that is connected to an electrode of the discharge of the discharge lamp (16), said electrode not being connected to the ignition transformer (15).

Abstract: An inverter is coupled to an EL lamp by a high pass filter including a series capacitor and a shunt resistor. The resistor is coupled in parallel with the EL lamp. The high pass filter has a time constant greater than 0.005 seconds and the capacitor has a capacitance at least ten times the capacitance of the EL lamp.

Abstract: The present invention is a lighting device for an electronic or electromechanical apparatus such as a timepiece of the wristwatch type. The invention including a device displaying time-related or other information, this lighting device including a light source for lighting the display device. The lighting device is characterized in that the light source is also able to measure the intensity of the ambient light. The invention also concerns a method for controlling the lighting of an apparatus of the aforementioned type.

Abstract: A lamp stand with multi-stage light modulation includes plural resistors annularly arranged to form a circular space. The resistors have terminals soldered on the outer walls of U-shaped contact blades, with an empty position terminal provided in the circular space. A light-modulating controller extends in the lamp stand, having a rotor formed with plural slopes on an outer wall for rotor copper strips to rest thereon. A trigger diode is connected to the gate of a triac AC switch and a capacitor is connected to the trigger diode and the paralleled terminals of the resistors and to the main terminals of the triac AC switch. The light-modulating controller is rotated to let the rotor copper strips contact the contact strips of the resistors to turn on power and charge the capacitor. Different resistance values change the breakdown speed of the DIAC and control the gate of the TRIAC to change the voltage effective value of the lamp, thus reaching a goal of light modulating.

Abstract: A circuit arrangement and control thereof for igniting a high intensity discharge (HID) lamp, for reducing the variation of the resonant ignition voltage under the parasitic capacitive loading condition, and for increased circuit stability. The high frequency ignition voltage is only applied to the lamp during an ignition phase. The variation of the magnitude of the resonant ignition voltage with respect to the parasitic capacitance at the lamp leads is minimized by inserting a damping resistor in series with the ignition resonant capacitor. In a normal operation after ignition, the charge and/or discharge current of the ignition resonant capacitor is bypassed through a bypass device instead of flowing through a current sense resistor, so that only a chopper current flows through a sensor by paralleling a relatively high impedance resistor with the sensor.

Abstract: A switching device intended for igniting and operating a high-pressure discharge lamp, provided with a switch-mode power supply (smps) for supplying a controlled current to the lamp, and with a pre-conditioner for feeding the smps. The pre-conditioner is provided with a storage capacitor. The switching device also includes an ignition circuit including a pulse capacitor and a switch for generating ignition-voltage pulses for igniting the lamp. The pulse capacitor, having a capacity of CF, is energized from the storage capacitor via an ohmic resistor.

Abstract: A power supply system for an automobile vehicle headlight discharge lamp, the system including a DC/DC converter with a capacitor at its output, a DC/AC converter powered by the voltage across said capacitor, and a module for generating a high-voltage breakdown pulse designed to be connected in series with said discharge lamp to the output of the DC/AC converter, wherein it further includes a module for heating the electrodes of the discharge lamp design to be connected in series with the discharge lamp and the high-voltage pulse generator module and adapted to deliver, after the high-voltage breakdown pulse, a decreasing voltage which, at the terminals of said discharge lamp, is added to the voltage across the capacitor at the output of the DC/DC converter.

Abstract: An auxiliary lighting control circuit and method for a lighting system having a HID lamp as the primary light source and an auxiliary light source for providing light when the HID lamp is extinguished or below full brightness but power remains available to the circuit. The circuit senses the HID lamp current and activates a relay to a conductive state using a solid state controller when the HID lamp current is below a predetermined current magnitude to effect the lighting of the auxiliary light source.

Abstract: An arrangement for controlling the activation of an electrical appliance. The arrangement utilizes a capacitive sensor to recognize the physical proximity of a user (e.g., a hand) to an internal capacitive sensing means. The capacitive change is applied as an input to an electrical control circuit so as to ultimately provide an electrical control signal to an associated electrical appliance. The arrangement does not require direct physical contact to activate any appliance, and may be used to control various power levels associated with a particular electrical appliance (e.g., light intensity for a "dimmer" switch, sound volume for an audio system, activation and trigger signals to an alarm system). The arrangement may be embedded within the wall of a structure (i.e., not visible) and still provide the capacitively-activated control function.

Abstract: A strobe device according to the present invention includes: a main capacitor; and step-up means including at least one step-up capacitor, the at least one step-up capacitor being rapidly charged via a flash discharge tube in an ionization state, a charged voltage of the at least one step-up capacitor being superimposed on a charged voltage of the main capacitor and applied across the flash discharge tube at least via an insulated gate bipolar transistor and a restriction resistor coupled in series with the flash discharge tube.

Abstract: The spectral energy characteristic of a discharge lamp is controlled by changing the density of the fill substance. The spectral characteristic can be shifted while substantially maintaining its shape by changing the density of the fill. A sulfur or selenium containing discharge lamp which is operated at a pressure of at least about 1 atmosphere contains a low ionization potential substance in the fill. Characteristics which are improved are one or more of spatial color uniformity, extinguishing characteristics, and bulb starting reliability. Particular substances which are added to the fill are alkali metal containing substances, III B metal containing substances, and alkaline earth metal containing substances. When light is reflected back into the bulb, the light which is re-emitted is stronger in the higher wavelengths.

Abstract: The invention relates to a circuit arrangement for operating a discharge lamp. According to the invention the series connection of a PTC thermistor V1 with a bi-directionally acting breakdown voltage component V2 is disposed parallel to the inductance L1 and/or the capacitor C1 in a load circuit which has a discharge lamp H1, an inductance L1 connected in series with the discharge lamp and a capacitor C1 disposed parallel to the discharge lamp H1, wherein the PTC thermistor V1 and the bi-directionally acting breakdown voltage component V2 are thermally coupled. The object of the invention is to provide a simple circuit arrangement for operating a discharge lamp which allows a substantially constant ignition of a discharge lamp.

Abstract: A ballast circuit for a fluorescent lamp including a magnetic choke electrically connected between the lamp and a power supply and an electronic starter circuit electrically coupled across said lamp, which ballast circuit is configured to provide a power factor of at least 90%. To this end, for certain lamps a power factor correcting capacitance is electrically connected across the power supply. For other lamps, a power factor correcting resistance is coupled between the ballasting capacitance and inductor so that the inductor and ballasting capacitance close to resonance.

Abstract: A ballast for a gas discharge lamp circuit has a d-c output which contains three series-connected diodes connected across the output terminals, a pair of capacitors connected from different respective nodes of the diodes to respective ones of the output terminals, and a resistor connected between two of the diodes. The resistor increases the circuit power factor to greater than 0.95.

Abstract: To ensure ignition of a high-pressure discharge lamp, for example a metal vapor halogen high-pressure dicharge lamp which has an ignition circuit, and is operated by direct current from an inverter circuit controlled for pulse width modulation, current flow to the lamp is extended in time upon initial energization thereof so that an initial hot spot which forms on an electrode can remain hot to establish a stabilized arc. This extension of current flow can be obtained by an R/C circuit in parallel to the output or storage capacitor (C.sub.A) of the inverter circuit (FIG. 1) or by an NTC resistor (H) in series with the lamp, or by a resistor which is short-circuited by a relay contact as the lamp operates, or the like.

Abstract: A starter circuit is supplied with 120 volt 60 Hz power, and is coupled to a gas discharge lamp having in an interior thereof a gas and two spaced electrodes. When the starter circuit applies to the electrodes a voltage in excess of a threshold voltage, the lamp transitions from a non-conductive state in which no visible light is emitted to a conductive state in which visible light is emitted. The starter circuit includes several voltage doubler circuits coupled in series with each other between the electrodes of the lamp to form a voltage multiplier circuit. When the lamp is in its non-conductive state, the voltage doubler circuits each output a substantially DC voltage which is twice the maximum potential of the 120 volt input signal so that the voltage multiplier as a whole applies to the electrodes a significant DC voltage in excess of the threshold voltage so that the lamp transitions from its non-conductive state to its conductive state.

Abstract: An inverter-type fluorescent lamp ballast is powered from the power line by way of a common and either of two (or more) different power leads. When powering the ballast by way of the common and the first one of these two power leads, the power provided to the ballast's fluorescent lamp load is relatively low; when powering the ballast by way of the common and the second one of these two power leads, the power provided to the ballasts's fluorescent lamp load is relatively high. In a lighting system, the power leads from each of several such ballasts are parallel-connected and controllably powered from the power line by way of a combination of two ordinary single-pole single-throw wall switches; such that when one of the two wall switches is in its ON-position, the amount of light provided is relatively low; but when the other one of the two wall switches is in its ON-position, the amount of light provided is relatively high.

Abstract: In an electron beam generator where the heating current for the cathode is transformed by an insulating transformer 7 disposed on the high-voltage insulator 4 of the beam head, the primary winding of this insulating transformer 7 being connected to ground potential, and where a single-pole high-voltage connection 2 and a single-pole high-voltage cable 2 connect the beam head 3 to a high-voltage generator 1, the high-voltage cable 2, at its terminal ends, has a protective resistor 10 corresponding to the surge impedance of the high-voltage cable 2 in order to reduce the damages to insulating and component parts.

Abstract: A novel lighting equipment for providing bright illumination with limited surge, including a capacitor connected in parallel with an incandescent lamp, the capacitor having a capacitive reactance lower than the resistance of the filament at ambient temperature; an impedance having a time constant connected between the capacitor and an ac source; and means for rectifying the current from the ac source.

Abstract: A discharge-lamp lighting device comprises a voltage generating circuit for generating a high-frequency voltage for lighting a discharge lamp, a self-oscillating device provided in the path of lamp current flowing through the discharge lamp for exciting the voltage generating circuit to self-oscillation, a direct current blocking element connected in series with the self-oscillating device for blocking the flow of a direct current in the self-oscillating device, and a bypass element connected in parallel with the direct current blocking element and the self-oscillating device for bypassing the direct current.

Abstract: An improved, more energy efficient reactor-type ballasting circuit for fluorescent lamps includes an inductive ballasting coil for directly applying an AC line voltage to the cathodes of a lamp without an intermediate autotransformer and also includes a glow type thermal switch in series with a positive temperature coefficient (PTC) resistor for electrical connection across the cathodes of the lamp to conduct pre-heating current to the lamp cathodes. The PTC resistor will effectively remove the glow switch from the ballast circuit if the switch fails to open after an appropriate time delay.

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: A power supply is provided for an arc discharge lamp (38) which includes a relatively low voltage high current power supply section and a high voltage starter circuit (10). The low voltage section includes a transformer (15), rectifier (24), variable resistor (26) and a bank of capacitors (28), while the starter circuit (10) comprises a plurality of diodes (D1 to D12) and capacitors (C1 to C12) connected as a Cockcroft-Walton multiplier. The starting circuit is effectively bypassed when the lamp arc is established and serves to automatically provide a high starting voltage to re-strike the lamp arc if the arc is extinguished by a power interruption.

Abstract: To provide for reliable ignition of low-pressure discharge lamps, particularly compact fluorescent lamps, operated at high frequency, for example in the order of about 45 kHz, an ignition circuit is connected in parallel to the lamp and serially with the electrodes (16, 17) thereof, which comprises a limiting capacitor (19) and the parallel circuit of a positive temperature coefficient (PTC) resistor (20) and a starting capacitor (18). The two capacitors (18, 19), together with an inductance (13, 14) in the operating circuit of the lamp, and a further capacity formed by a blocking capacitor (15), after preheating of the lamp electrodes by current flowing through the initially cold PTC resistor, will cause voltage rise across the resonance capacitors (18, 19) which will cause ignition of the lamp.

Abstract: In a circuit for an inductively stabilized discharge tube (1) provided with two preheatable electrodes (2, 3) the ends of one electrode (2) are connected via a first capacitor (22) and a second capacitor (24), respectively, to the corresponding ends of the other electrode (3). The second capacitor (24) remote from the supply is shunted by a PTC resistor (23). The discharge tube (1) and inter alia the PTC resistor (23) form part of a lamp unit. The discharge tube (1) ignites readily even at low ambient temperatures. In the lamp operating condition, the influence of the PTC resistor (23) is neglible.

Abstract: For the glow discharge between a receptacle and a workpiece, the glow discharge path is connected in series with a first switch. A capacitor circuit is charged via the glow discharge path and two diodes. By closing a switch, the previously positive pole of the capacitor circuit is set to the zero potential, whereby the potential of the other pole is shifted negative. By closing a switch, the capacitor circuit is discharged through the glow discharge path while the first switch is closed. Upon the discharging of the capacitor circuit, the supply voltage continues to be present at the glow discharge path for the remaining pulse time. In the initial range, the voltage pulses have a pulse peak for ignition followed by a maintenance range, the height of which corresponds to the supply voltage.

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

Abstract: A current limited strobe charging circuit in which the charging current is automatically limited during the time required to reform the primary storage capacitor after a long period of non-use without materially effecting the current flow and time required to subsequently recharge the storage capacitor after it has been reformed includes a positive temperature coefficient resistor serially connected therewith to switch from a low resistance mode of operation to a high resistance mode of operation as a result of its own internally generated I.sup.2 R heat.

Abstract: Various embodiments of direct current (D.C.) ballasting circuits for low wattage high pressure sodium (HPS) vapor lamps are disclosed. In one ballast embodiment a negative going high voltage pulse is applied directly to the H.P.S. lamp cathode during the starting operation and the ballast circuit preferentially diverts a major portion of the HPS lamp current around a high-voltage transformer during normal operation so as to reduce the resistive heating of the transformer. In a second ballast embodiment, capacitors are arranged into voltage multiplying circuit for generating the high D.C. starting voltage along with diodes that reduce the power dissipation of the ballast circuit.