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Circuit Archives
Measurement & Control Circuits/ Environmental
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Differential
Capacitance Measurement Circuit for Tilt Meter
Reprinted with permission
from Rudolf Graf.
For this and over 1000 other electronic circuits, review and order Rudolf
Graf's Encyclopedia of Electronic Circuits on CD-ROM Vol-1
McGraw-Hill ISBN0078528119
FB104-2 |
Description:
A bubble vial with
external aluminum-foil electrodes is the sensing element for simple indicating tiltmeter.
To measure bubble displacement, a bridge circuit detects the difference in capacitance
between the two sensing electrodes and the reference electrode. Using this circuit,, a
tiltmeter level vial with 2 mm deflection for 5 arc-seconds of tilt easily resolves 0.05
arc-second. The four diodes are CA3039, or equivalent. (NASA, Tech Briefs, Fall/Winter
1981, P.319.) From figure FB104-2 from Encyclopedia of
Electronic Circuits Vol. 1.
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