Abstract: A controller for reducing acoustic noise produced during use of a leading edge dimmer, includes a leading edge controller responsive to an input voltage fed thereto for producing a control signal upon detection of a leading edge, and a linear switch coupled to the leading edge controller and responsive to the control signal for linearly switching the input voltage so that a rate of rise of the leading edge is decreased. A trailing-edge controller may be coupled to a leading-trailing edge detector and responsive to detection of a trailing edge dimmer for disabling the leading edge controller and decreasing a rate of decline of the trailing edge of the input voltage.

Abstract: A controller for reducing acoustic noise produced during use of a leading edge dimmer, includes a leading edge controller responsive to an input voltage fed thereto for producing a control signal upon detection of a leading edge, and a linear switch coupled to the leading edge controller and responsive to the control signal for linearly switching the input voltage so that a rate of rise of the leading edge is decreased. A trailing-edge controller may be coupled to a leading-trailing edge detector and responsive to detection of a trailing edge dimmer for disabling the leading edge controller and decreasing a rate of decline of the trailing edge of the input voltage.

Abstract: An electronic ballast for supplying operating power to a high-intensity discharge (HID) lamp. The ballast includes a full-wave rectifier connected to an AC power line to produce an unregulated pulsating DC output which is applied to a power factor correction (PFC) circuit. The PFC circuit includes a first semiconductor electronic switch whose activation is controlled to bring the input current and voltage in time-phase with one another, thereby imparting a high power factor rating to the ballast. The pulsating DC output of the PFC circuit is applied to a storage capacitor circuit which is charged thereby, the capacitor circuit including a second electronic switch whose activation is controlled to discharge the capacitor so as to cause the capacitor circuit to yield in its output, a regulated DC which is fed to a power control (PC) circuit. The PC circuit includes a third electronic switch whose activation is controlled to maintain the wattage of power supplied to the HID lamp at the rated wattage of the lamp.

Abstract: A track lighting hybrid illumination system comprising a power supply circuit (11, 41, 22) having an input for connecting to a voltage source (12, 42) of low frequency for providing an output voltage with altered electrical characteristics, and a pair of conductors (19, 23, 43, 48) coupled to an output of the power supply circuit. A first lamp (29, 25, 31) is coupled to the conductors via a second power supply circuit (28, 26, 34), and at least one further lamp (29, 24, 25, 31) with electrical power requirements of a different characteristic to the first lamp coupled to the conductors.

Abstract: An electronic ballast for supplying operating power to a high-intensity discharge (HID) lamp. The ballast includes a full-wave rectifier connected to an AC power line to produce an unregulated pulsating DC output which is applied to a power factor correction (PFC) circuit. The PFC circuit includes a first semiconductor electronic switch whose activation is controlled to bring the input current and voltage in time-phase with one another, thereby imparting a high power factor raring to the ballast. The pulsating DC output of the PFC circuit is applied to a storage capacitor circuit which is charged thereby, the capacitor circuit including a second electronic switch whose activation is controlled to discharge the capacitor so as to cause the capacitor circuit to yield in its output, a regulated DC which is fed to a power control (PC) circuit. The PC circuit includes a third electronic switch whose activation is controlled to maintain the wattage of power supplied to the HID lamp at the rated wattage of the lamp.

Abstract: A radio communication device, which transmits or receives a signal at a predetermined carrier frequency. The device includes a reference oscillator, which generates a clock frequency having a clock frequency error relative to a specified frequency thereof, a processor, which estimates the clock frequency error and parses the error to determine coarse and fine error correction components, at least one frequency synthesizer, which responsive to the clock frequency and to the coarse error correction component, generates a partially corrected frequency having a residual frequency error, which partially corrected frequency is applied to process the signal and baseband processing circuitry, which applies the fine error correction component to process the signal so as to correct the residual frequency error.

Abstract: A track lighting hybrid illumination system comprising a power supply circuit having an input for connecting to a voltage source of low frequency for providing an output voltage with altered electrical characteristics, and a pair of conductors coupled to an output of the power supply circuit. A first lamp is coupled to the conductors via a second power supply circuit, and at least one further lamp with electrical power requirements of a different characteristic to the first lamp coupled to the conductors.

Abstract: An electronic transformer for lighting includes a rectifier coupled to an inverter an output transformer (T1, T10) and a drive transformer (T2, T11). A protection mechanism (VR1, VR2) is responsively coupled to a winding of the output transformer and to a winding of the drive transformer such that the voltage across each of the windings are approximately equal and opposite during normal operation but differ substantially during a short-circuit.

Abstract: A low voltage illumination system, comprising a pair of terminals for connecting to a source of low frequency a.c. voltage, a frequency converter coupled to the source of a.c. voltage for converting the low frequency a.c. voltage to high frequency a.c. voltage, and a step down transformer coupled to an output of the frequency converter for converting to high frequency, low voltage a.c. A synchronous rectifier is coupled to a secondary of the step down transformer for converting the high frequency low voltage a.c. to a low magnitude nominally d.c. voltage, and a pair of conductors is connected to the low magnitude nominally d.c. voltage for connecting low voltage lamps thereto. Optionally, the step down transformer is of planar design and an integral overload protection circuit is provided responsive to a drop in output impedance across the conductors commensurate with an overload for interrupting power thereto.