Strain gauge

US4884453A · kind A · utility

Assignee

• Alcatel N.V. · NL

Inventors

• Horst Hoffmann · Pentling, DE
• Peter Kersten · Leonberg, DE
• Hans Volz · Schwieberdingen, DE
• Ulrich Seyfried · Stuttgart, DE

Key dates

• Filing date: Jul 22, 1988
• Grant date: Dec 5, 1989
• Expiry date: Jul 22, 2008

Classification

• Technology area (CPC G): Physics
• CPC primary: G01L1/125
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A strain gauge comprised of a premagnetized ferromagnetic film wherein any change in length of the film can be measured by employing the properties of magnetostriction and magnetoresistance. The strain gauge is deposited on a substrate by thin-film techniques and has a very high sensitivity. Preferably, two electrically insulated strips parallel strips of amorphous metal film have (in the absence of strain) respective directions of magnetization aligned antiparallel to one another and are connected electrically at one end. Such an arrangement facilitates the reversion of the magnetization back to its easy direction when the stress causing the strain is removed.