EP0196735A2
Expired / Lapsed
EP
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Differential capacitance detector
Assignee: Lucas Sensing Systems Inc
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Filing: 1986-01-16
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Granted: —
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Expires: 2006-01-16
Abstract
Abstract A differential capacitance detector comprising two pulse generators (3, 6) and a comparator (7). The width of each pulse generator output is representative of the capacity of each of two capacitors (2, 5) whose differential is to be determined. The comparator (7) provides a third pulse whose width is the difference of th width of the pulses input from the pulse generators (3, 6) and is representative of the capacitance differential between the two capacitors (2, 5).
Inventors
- 👤 Harold Lee Swartz
- 👤 Jeffrey Clark Heidel
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 04:30
CPC Classifications
G; G01; G01D; G01D5/00; G01D5/12; G01D5/14; G01D5/24; G01D5/241; G01D5/2417; G01C; G01C9/00; G01C9/02; G01C9/06; G01C9/12
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
100 words
A differential capacitance detector characterised in that it comprises first pulse generator means (3) for generating a first pulse (9) having a width representative of a capacitance value of a first capacitor (2), second pulse generator means (6) for generating a second pulse (10) having a width representative of a capacitance value of a second capacitor (5), and comparator means (7, 42) coupled to receive the first and second pulses (9, 10) for providing a third signal representative of pulse width differences between the first and second pules, thereby representative of the capacitive difference between the first and second capacitors.
Claim 2
Dependent Claim
100 words
A differential capacitance detector characterised in that it comprises first pulse generator means (3) for generating a first pulse (9) having a width representative of a capacitance value of a first capacitor (2), second pulse generator means (6) for generating a second pulse (10) having a width representative of a capacitance value of a second capacitor (5), and comparator means (7, 42) coupled to receive the first and second pulses (9, 10) for providing a third signal representative of pulse width differences between the first and second pules, thereby representative of the capacitive difference between the first and second capacitors.
Claim 3
Dependent Claim
35 words
A differential capacitance detector according to claim 1, characterised in that the comparator means (7) includes means (27) for providing a signal to indicate which of the first and second pulses is of greater width.
Claim 4
Dependent Claim
37 words
A differential capacitance detector according to claim 2, characterised in that the means for providing a signal to indicate which of the first and second pulses (9, 10) is of greater width is in R-S flip-flop (27).
Claim 5
Dependent Claim
67 words
A differential capacitance detector according to any of the preceding claims, characterised in that the first and second pulse generator means respectively include first and second monostable multivibrators (3, 6) which are coupled to first and second fixed resistors (1, 4) and to the first and second capacitors (2, 5), thereby establishing RC time constants that determine the widths of the first and second pulses (9, 10).
Claim 6
Dependent Claim
43 words
A differential capacitance detector according to any of the preceding claims, characterised in that the comparator means (7) further includes an exclusive OR gate (28) coupled to receive the first and second pulses (9, 10) to provide said third signal as a pulse.
Claim 7
Dependent Claim
88 words
A differential capacitance detector according to claim 1, characterised in that the comparator means (42) includes first and second integrator means (40, 41) coupled to receive the first and second pulses (9, 10) respectively, for providing first and second DC voltage signals representative of integrated values, and a difference amplifier (22) coupled to receive the first and second DC voltages to provide a DC output voltage representative of differences between the first and second DC voltages and thereby capacitive differences between the first and second capacitors (2, 5).
Claim 8
Dependent Claim
28 words
A differential capacitance detector according to claim 6, characterised in that each first and second integrator means (40, 41) comprises an R-C integrator network (18, 20, 19, 21).
References Cited (Backward Citations)
No citation records indexed.
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