Showing papers on "Inductive sensor published in 1969"

Precision presence detector

Abstract: This disclosure relates to a precision presence detector having an oscillating amplifying means which is normally in a nonoscillating condition. The oscillating means includes a first and a second inductive sensing element which are positioned in a predetermined relationship with each other so that essentially zero magnetic coupling normally exists between the two sensing elements. The presence detector also employs an inert type of tuning means which is normally tuned to a given frequency. The tuning means includes a first and a second tuned inductive element which are spaced in the same predetermined relationship as the inductive sensing elements. Thus, the oscillating amplifying means will begin oscillating whenever the first and second tuned inductive elements of the tuning means are substantially directly aligned with and in proximity to the first and second inductive sensing elements.