Circuits for operating discharge lamps
First Claim
1. An electrical circuit for operating an electrical discharge lamp, the circuit comprising:
- a pair of terminals for connection to a supply of voltage of substantially sinusoidal waveform;
a second pair of terminals for connection with a discharge lamp;
a ballast impedance connected between one of the first pair of terminals and one of the second pair of terminals;
a starting device for aiding initiation of discharge in the lamp; and
means for disabling the starting device when a discharge has been initiated in the lamp,wherein the means for disabling the starting device is arranged to detect a change in the voltage waveform across the second pair of terminals from substantially sinusoidal to substantially square.
1 Assignment
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Accused Products
Abstract
An electrical circuit for operating an electrical discharge lamp has a pair of terminals for connection to a supply of voltage of substantially sinusoidal waveform, a second pair of terminals for connection with a discharge lamp, a ballast impedance connected between one of the first pair of terminals and one of the second pair of terminals, a starting device for aiding initiation of discharge in the lamp and means for disabling the starting device when a discharge has been initiated in the lamp. The means for disabling the starting device operates in response to a change in the voltage waveform across the second pair of terminals from substantially sinusoidal to substantially square.
9 Citations
3 Claims
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1. An electrical circuit for operating an electrical discharge lamp, the circuit comprising:
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a pair of terminals for connection to a supply of voltage of substantially sinusoidal waveform; a second pair of terminals for connection with a discharge lamp; a ballast impedance connected between one of the first pair of terminals and one of the second pair of terminals; a starting device for aiding initiation of discharge in the lamp; and means for disabling the starting device when a discharge has been initiated in the lamp, wherein the means for disabling the starting device is arranged to detect a change in the voltage waveform across the second pair of terminals from substantially sinusoidal to substantially square. - View Dependent Claims (2, 3)
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Specification