Patent ID: 6448795
Filing Date: 2002-09-10
Classification: G01N

Abstract:
An apparatus for measuring the electrical conductance of a sample and said apparatus comprising:a radio frequency generator with output at an operating frequency, an inductive driver means connected to said radio frequency generator, a pair of inductive sensing means in close proximity to said inductive driver means, one of said pair of inductive sensing means being in closer proximity to said sample than the other of said pair of inductive sensing means, and each of said pair of inductive sensing means providing a radio frequency signal, a pair of radio frequency amplitude detectors, each thereof connected to separate ones of said pair of inductive sensing means, and each of said pair of radio frequency amplitude detectors providing an amplitude signal, and a subtraction device connected to said pair of radio frequency amplitude detectors, wherein said electrical conductance of said sample is derived from the difference of said two amplitude signals.