The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 12, 1991
Filed:
Apr. 10, 1989
Michael D Crossfield, Halse, Brackley, Northamptonshire, GB;
Other;
Abstract
A housing contains a pick-up coil for detecting an external magnetic field; a power supply; a tone generator; and an electric circuit powered by said power supply and arranged to activate said tone generator in response to an output from said magnetic field pick-up including a piezoelectric material surrounded about its circumference by a thin layer of magnetostrictive material. Since the electrical output of the piezoelectric material is dependent on the stress imparted to it by the magnetostrictive material, and since the dimensional change in the magnetostrictive material is proportional to the magnetic field in the environment in which the magnetostrictive material is located, the electrical output of the piezoelectric material provides a measure of magnetic field strength.