Dimmer for fluorescent and incandescent lamps
First Claim
1. A universal brightness control circuit for both arc discharge lamps having a ballast and for incandescent lamps connected to a source of electrical power comprising:
- rectifier means connected in series between the source of electrical power and the lamp for converting the electrical power into direct current, andvariable dimming control means connected to the output of said rectifier means and powered by the converted direct current to control the amount of current supplied through the lamp or ballast without significantly reducing the full 360°
conduction angle of the electrical power supply.
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Accused Products
Abstract
A universal dimmer which can be used for both fluorescent lamps having a ballast and for incandescent lamps connected to either an alternating or direct current power supply. The dimmer can be installed in place of a standard wall-mounted light switch and connected to the existing wiring. The dimmer circuitry has a fullwave diode rectifier bridge connected in series with the lamp for converting the alternating current power into direct current. A variable current limiting circuit is connected in series with the DC output of the rectifier bridge and is powered by direct current to control the amount of current supplied through the lamp and ballast. The current limiting circuit includes a power transistor which acts as a variable resistor and controls the lamp current and an operational amplifier coupled with a voltage divider network that establishes a selectively variable reference voltage which controls the amount of current through the lamp. The fullwave rectifier bridge supplies a small amount of power to the control circuitry. The current limiting circuit allows continuous dimming control from full light output to zero output of both arc discharge lamps and incandescent lamps by limiting the current through the lamp without significantly reducing the electrical conduction angle of the alternating current power supply below 360 degrees and will also control dimming of systems powered by direct current.
46 Citations
18 Claims
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1. A universal brightness control circuit for both arc discharge lamps having a ballast and for incandescent lamps connected to a source of electrical power comprising:
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rectifier means connected in series between the source of electrical power and the lamp for converting the electrical power into direct current, and variable dimming control means connected to the output of said rectifier means and powered by the converted direct current to control the amount of current supplied through the lamp or ballast without significantly reducing the full 360°
conduction angle of the electrical power supply. - View Dependent Claims (2, 3, 4, 5)
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6. A universal brightness control circuit for both arc discharge lamps having a ballast and for incandescent lamps connected to a source of electrical power comprising;
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rectifier means connected in series between the source of electrical power and the lamp or ballast for converting the electrical power into direct current, said rectifier means comprises a fullwave diode bridge having a first input terminal connected to the lamp or ballast, a second input terminal connected to the source of electrical power, a first common output terminal, and a second output terminal connected to said variable dimming control means for supplying direct current thereto. variable dimming control means connected to the output of said rectifier means and said lamp and powered by the converted direct current, said variable dimming control means includes a current limiting power transistor which acts as a variable resistor, and an operational amplifier coupled with a voltage divider network which establishes a selectively variable reference voltage to selectively control the amount of current supplied through the lamp or ballast without significantly reducing the full 360°
conduction angle of the electrical power supply. - View Dependent Claims (7, 8, 9, 12, 13, 14, 15, 16, 17, 18)
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10. A universal brightness control circuit according to claim 10 in which
said second capacitor serves as a noise filter to maintain the controlled amount of current steady.
Specification