The present invention relates to a method and apparatus for remotely detecting impedance. It is specifically adapted for use on a polishing machine wherein the end point of polishing for removing a surface layer during the processing of semiconductor substrates is detected. A first, or stationary coil...http://www.google.es/patents/US5132617?utm_source=gb-gplus-sharePatente US5132617 - Method of measuring changes in impedance of a variable impedance load by disposing an impedance connected coil within the air gap of a magnetic core
Method of measuring changes in impedance of a variable impedance load by ...
