Electricity: measuring and testing – Impedance – admittance or other quantities representative of... – Lumped type parameters
Reexamination Certificate
2007-04-05
2009-12-08
Nguyen, Vincent Q (Department: 2831)
Electricity: measuring and testing
Impedance, admittance or other quantities representative of...
Lumped type parameters
C324S686000, C324S663000, C324S664000
Reexamination Certificate
active
07629797
ABSTRACT:
Methods and systems for improving the sensitivity of a variety of conductivity sensing devices, in particular capacitively-coupled contactless conductivity detectors. A parallel inductor is added to the conductivity sensor. The sensor with the parallel inductor is operated at a resonant frequency of the equivalent circuit model. At the resonant frequency, parasitic capacitances that are either in series or in parallel with the conductance (and possibly a series resistance) is substantially removed from the equivalent circuit, leaving a purely resistive impedance. An appreciably higher sensor sensitivity results. Experimental verification shows that sensitivity improvements of the order of 10,000-fold are possible. Examples of detecting particulates with high precision by application of the apparatus and methods of operation are described.
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Li Wei
Shih Chi-yuan
Tai Yu-Chong
Zheng Siyang
California Institute of Technology
Milestein Zhang & Wu LLC
Milstein Joseph B.
Nguyen Vincent Q
Zhu John
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