A Simple Capacitive Displacement Measuring System

Item

Title
A Simple Capacitive Displacement Measuring System
Date
1964
Index Abstract
Not Available
Photo Quality
Complete
Report Number
AMRL TR 64-116
Creator
Hoeft, Lothar O.
Corporate Author
Biophysics Laboratory
Laboratory
Biophysics Laboratory
Extent
22
Identifier
AD0610286
Access Rights
CFSTI
Distribution Classification
1
Contract
Laboratory Research - No Contract
DoD Project
7232
DoD Task
723204
DTIC Record Exists
No
Distribution Change Authority Correspondence
None
Distribution Conflict
No
Abstract
This report presents the theory, development and performance of a capacitive displacement detector. The detector senses the displacement changes as changes in the capacitance of a probe located near the body whose displacement is being measured. These capacitance changes are converted into frequency changes by placing the capacitance probe in the tank circuit of an oscillator. The frequency changes are converted into voltage changes by standard FM techniques. The capacitance detector has a sensitivity of 30 volts/rho farad. When used with a 0.2 cm diameter probe, the displacement sensitivity was 4.78 volts/cm when the probe to surface distance was 0.1 cm. The noise level was low enough so that the system was able to measure displacements of the order of .00001 cm at frequencies below 1000 cps and displacements of the order of 5 x .000001 cm at frequencies above 1000 cps. The main advantages of this type of displacement detector over others is the ease of construction and adjustment.
Report Availability
Full text available
Date Issued
1964-12
Provenance
RAF Centre of Aviation Medicine
Type
report
Format
1 online resource
Media
AMRLTR64-116.pdf