Electric lamp and discharge devices: systems – Pulsating or a.c. supply – Induction-type discharge device load
Patent
1994-03-14
1995-10-31
Pascal, Robert J.
Electric lamp and discharge devices: systems
Pulsating or a.c. supply
Induction-type discharge device load
315209R, 315240, 315DIG4, 315307, H05B 4116
Patent
active
054632854
ABSTRACT:
The resolution .DELTA.C of a binary capacitance ladder having a plurality of N branches is precisely determined by appropriately selecting the value of a fixed capacitor in each branch relative to the parasitic capacitance of a corresponding series-connected switch. The capacitance of each respective branch varies by 2.sup.n-1 .DELTA.C, where n is the number of the branch, adjacent branches being numbered sequentially. The total capacitance is variable between C.sub.Total and C.sub.Total -(2.sup.N -1).DELTA.C in steps of .DELTA.C, where C.sub.Total is the sum of the capacitances in the ladder with all switches closed, and C.sub.Total -(2.sup.N -1).DELTA.C is the capacitance of the ladder with all switches open. For any particular branch of the ladder, the switch capacitance may be further controlled by adding a fixed capacitance in parallel with the respective switch. Such a variable capacitance is useful as a tuning capacitor in an electrodeless HID lamp ballast.
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Breedlove Jill M.
General Electric Company
Pascal Robert J.
Ratliff Reginald A.
Snyder Marvin
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