Communications: electrical – Condition responsive indicating system – Specified housing
Patent
1991-10-28
1994-11-15
Peng, John K.
Communications: electrical
Condition responsive indicating system
Specified housing
340578, 431 79, G08B 2300, G08B 1712, F23N 508
Patent
active
053652231
ABSTRACT:
A circuit for detecting whether the level of an electrical signal having a preselected polarity is above a preselected value, is powered by DC of the opposite polarity. This prevents current leakage within the detector circuit from simulating the level of the electrical signal. Such a circuit is particularly suited for detecting the current level provided by a flame sensor in a combustion control system. The preferred embodiment has a capacitor which is charged by the circuit and then discharged by the electrical signal. The time required to discharge the capacitor to a preselected level indicates the level of the electrical signal. A second embodiment uses a comparator in a feedback loop which allows sensing the level of a voltage outside of the voltage range defined by the comparator's power supply.
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Patent Abstracts of Japan, vol. 9, No. 194 (M-403) (1917), re Japanese publication 60-57126, Aug. 1985.
Honeywell Inc.
Mullen Jr. Thomas J.
Peng John K.
Schwarz Edward L.
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