Capacitive/Eddy-Current Sensors Comparison

Capacitive and Eddy-Current Sensors have distinct advantages and disadvantages. The comparison table below will help you determine the best technology for your measurement.

The values below are typical for standard uses. We regularly create custom products and calibrations that exceed the listed values.

Parameter	Capacitive	Eddy Current
Resolution @ 10kHz	0.004% of Full Scale`	0.008% of Full Scale
Maximum Bandwidth	15kHz	80kHz
Evironmental	Requires clean, dry environment	Tolerates hostile, wet environments
Submersible (Probes only)	Only in unique circumstances	Yes
Probe Temperature Range	0°C to 50°C (30°F to 120°F)	-40°C to +200°C (-40°F to 400 °F)
Typical Range/Diameter Ratio	1:8	1:3
Material Sensitivity	Measures all conductors equally. Sensitive to material changes when measuring nonconductors	Significant sensitivity to changes between ferrous and nonferrous materials (aluminum vs. steel). Slight sensitivity to changes within ferrous or nonferrous materials (alumium vs. brass). Optimal performance requires calibration to specific material.
Target Materials	Conductors, semiconductors, nonconductors	Conductors only
Errors due to Target Motion	None	None with nonferrous targets. Moving, ferrous targets exhibit electrical runout (small output changes due to changes in target molecular structure). These errors are small and techniques exist to minimize or eliminate this error source if necessary.
Minimum Target Size	130% sensor diameter	300% sensor diameter
Minimum Target Thickness	No limit.	Varies depending on material. Ranges from 0.01mm to 1.6mm. See Minimum Thickness TechNote for more information.
Vacuum Compatibility (Probes only)	Available	Available
Cost	$$	$