Abstract: A phase controller includes a plurality of pulse width modulation (PWM) circuits, a plurality of switching devices, a computing unit, and a latency generator. The plurality of PWM circuits output pulse signals. The plurality of switching devices are coupled to the respective plurality of PWM circuits, and switch on and off based on the pulse signals. The computing unit calculates the pulse signals to be output from the plurality of PWM circuits, based on outputs of the plurality of switching devices. The latency generator generates latency in any of the pulse signals so that edge positions of the pulse signals output from the plurality of PWM circuits do not collide with each other, wherein the pulse signals change values at the edge positions.

Abstract: A circuit is used to indicate different statuses of a component of a computer system. The circuit includes a port, an indicating device, and a control circuit. The port outputs different signals corresponding to different statuses of the component. The indicating device includes a first indicator and a second indicator each of which includes a positive end and a negative end. The positive end of the second indicator is connected to the negative end of the first indicator, and the negative end of the second indicator is connected to the positive end of the first indicator. The control circuit includes an input terminal, and a pair of output terminals connected to opposite ends of the first indicator. A polarity of an electric potential difference between the pair of output terminals is switched between negative and positive polarities according to the signal outputted by the port.

Abstract: A backlight used for a liquid crystal display includes a plurality of light emitting units, and a phase controller for adjusting the phase of the light emitting units. The light emitting units are turned on and off based on pulse signals of a predetermined cycle having an on-period and an off-period. Under the control of the phase controller, the light emitting units are turned on or off with different phases.

Abstract: A lamp power supply circuit for an image forming device, which is not provided with a full-wave rectifier and any additional noise reducing circuit but is capable of effectively suppressing inrush current not to produce noise that may cause erroneous operation of the image forming device and affect any external appliance. A lamp lighting control system for use in an image forming device, which can realize soft-starting of an exposure lamp or a fixing heater-lamp by gradually increasing a conducting angle .beta..sub.i (i=0, 1 . . . ) for applying a voltage to a lamp through phase control of an AC power-supply voltage V.sub.AC for an initial period of energizing the exposure lamp or the fixing heater-lamp. Wherein, the conducting angle is gradually increased per even-number unit of cycles of AC power-supply voltage V.sub.AC on the condition that even numbers of cycles in the same unit have the same conducting angle, e.g., .beta..sub.0 =.beta..sub.1 <.beta..sub.2 =.beta..sub.3 <.beta..sub.4 =.beta..sub.

Abstract: Disclosed is a new ac electric discharging power supply which is capable of permitting electric discharge to appear without difficulty even in the atmosphere of reduced gas pressure or even though undesired dielectric material should be accidentally adhered to the electrode surface, and in which power supply the plasma parameters vary hardly with time.The signal from master oscillator (1) is divided into a plurality of divisions by power divider (2), and each power division is controlled in phase and amplitude by phase-shifters (3) and power amplifiers (4). Oscillating frequency, phase and amplitude are controlled coordinately by control (7), and the final voltages appearing at the output terminals of power amplifiers (5) are applied to electrodes 6, which are arranged in an electric discharging vessel.One output terminals of all power transformers (5) are connected in common, ordinarily in floating condition, thereby permitting electric discharges to appear between selected electrodes (6).

Abstract: A dimming system, which provides a time-varying current from a power source between the electrodes of a gas discharge lamp, simultaneously provides high-frequency, low-level current between the electrodes to sustain an electric discharge in the lamp when the time varying current alone is insufficient. The system provides reduced starting stress in the lamp and, therefore, longer lamp life by delaying the formation of an arc discharge, during start-up, until the electrodes have been heated. The system can be used with standard magnetic ballasts to provide full-range dimming of gas discharge lamps from 3 to 100 percent light output with minimal striations, lamp drop out, and flicker.

Abstract: The invention provides a laser arrangement including in its discharge circuit a switching thyratron which is capable of conduction normally in one direction and protectively in the reverse direction. The thyratron has an anode formed as a hollow body which is adapted to retain plasma generated during a pulse of forward conduction so that the anode is provided to act as a cathode permitting protective reversal of the thyratron when this is subject to reversal of voltage.

Abstract: An illumination control system for gas discharge lamps which can be dimmed is provided in which a central inverter produces a sinusoidal output voltage at about 23 kHz. The amplitude of the inverter output is adjustable to dim the lamps. A transmission line consisting of spaced wires having respective thick insulation sheaths distributes the high frequency power to remotely located assemblies of ballasts and lamps. The ballasts consist of passive linear components. A high power factor rectifier network is disclosed for providing a d-c input to the inverter from the 50/60 Hz mains. The inverter circuit is provided with novel controls for gradual start-up and turn-off and is protected against load fault currents and internal fault currents. Automatic and manual resets are provided for internal fault current and load fault current, respectively. The basic inverter circuit consists of two alternately conducting controllably conductive power switching devices.