Abstract: Lighting fixtures and lighting systems for use in areas with high magnetic fields or areas that require low EMI emissions. The lighting systems include a non-ferrous lighting fixture having an LED light source and a control circuit. The LED light source includes one or more LEDs, and the control circuit provides a regulated operational current to the LED light source. The control circuit includes at least one switch for controlling the flow of current through the control circuit. The switch has a first state and a second state, and the operational current provided to the LED light source is increased and decreased in a linear manner based on the state of the at least one switch.

Abstract: Lighting fixtures and lighting systems for use in areas with high magnetic fields or areas that require low EMI emissions. The lighting systems include a non-ferrous lighting fixture having an LED light source and a control circuit. The LED light source includes one or more LEDs, and the control circuit provides a regulated operational current to the LED light source. The control circuit includes at least one switch for controlling the flow of current through the control circuit. The switch has a first state and a second state, and the operational current provided to the LED light source is increased and decreased in a linear manner based on the state of the at least one switch.

Abstract: This invention is a non-ferrous lighting fixture and non-ferrous lighting system that can be used in areas with high magnetic fields or that require low EMI emissions, such as MRI operating rooms. This invention uses LED's to provide a high-intensity, quality white or other color light that is softened by reflectors and diffusers, and can be dimmed to provide flexible lighting levels. The flexible lighting levels can range from the maximum light used for patient procedures and equipment servicing/maintenance to the lowest light level used to keep a patient comfortable while facing upward on the MRI scanning table. Moreover, by using an aluminum substrate printed circuit board, this invention resolves the thermal issues associated with high-intensity lighting. Not only does this invention resolve glare and hot spot issues, it protects the user and installer from electrical hazards associated with potentially high voltages, as well.

Abstract: A light fixture including a lamp and a replaceable light cartridge that is removably interconnected to the lamp. The lamp includes a base, an arm extending outwardly from the base, and a lamp housing coupled to the arm at the end of the arm opposite the base. The replaceable cartridge is connected to the lamp housing, and comprises a bulb and a bulb housing. The bulb is a fluorescent tube that is the light source for the light fixture. A ballast that is separate and independent from the bulb, and steps up the low voltage from a power source to the high voltage current required by the bulb. The ballast is disposed within the base and is interconnected to the replaceable cartridge with a quick disconnect plug. The separate ballast and bulb allow the bulb to be replaced independently of the ballast.

Abstract: A power supply for a gas discharge lamp is claimed. An input circuit receives power from a power source. An output transformer having a primary winding and a secondary winding and has a lamp connected in circuit across the secondary winding. First and second power switches switch power to the primary winding. The driver drives the power switches at a drive frequency. A tuned LC resonant circuit having a resonant frequency is connected in circuit between the driver and the lamp. A controller generates control signals to the driver at a first frequency that is functionally related to the drive frequency, and regulates the lamp current by controlling the difference between the resonant frequency and the first frequency.