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US 5,212,427 AGranted
Electronic lamp ballast dimming control means employing pulse width control
AssigneeAppliance Control Technology, Inc.
InventorWilliam H. Jones
Life of this patent
Estimating the term…
Abstract
An electronic ballast for use with fluorescent lamps including a dimming means consisting of a permanent magnet supported over and in proximity to a dual toroid coil assembly utilized as part of an included inverter circuit included in the ballast. The permanent magnet is movable to control the amount of saturation of the transformers thus determining the width of pulses generated by the transistors included in the inverter circuit and thereby controlling the intensity of light emitted from the fluorescent lamps.
Claims6
An electronic ballast connected to a fluorescent lamp comprising:
- an inverter circuit operated to convert direct current to high voltage alternating current;
- first and second transistors;
- and a dual toroid coil assembly functioning with said transistors to form said inverter circuit;
- dimmer control means consisting of a permanent magnet located in proximity to said dual toroid coil assembly to control the saturation of said dual toroid coil assembly, said saturation determining the width of pulses generated by said first and second transistors whereby said high voltage alternating current for operation of said fluorescent lamp is limited to control the intensity of light emitted therefrom:
- and support means for said permanent magnet.
2 more elements
Dependencies are inferred from the claim text.