Project Analog - November 2008 - (Page 5)

Selecting the Proper Amplifier for Strain Gauge Applications Contributed by Microchip Technology www.microchip.com Contents Viewpoint Selecting the Proper Amplifier Using a Digital Potentiometer to Optimize a Photo Detection Circuit Resistor Networks in Critical Applications Analog news T he world of data acquisition is extremely diverse, encompassing measurements of temperature, pressure, humidity, strain and a variety of other physical phenomenon. In addition, these measurements may be required under harsh conditions, such as extreme temperatures, centrifugal forces and electrically noisy environments. System designers must be diligent in not only selecting the correct sensor for their application, but also in designing appropriate signal conditioning to deal with these issues. This article will focus on the signal conditioning required in applications that use strain gauges and, more specifically, the parameters that may affect the selection of the amplifier or amplifiers used in conjunction with the strain gauges. IntroductIon to StraIn GauGeS Before jumping into a discussion of amplifiers and signal conditioning circuitry, it is worthwhile to quickly review strain gauges. By definition, “strain” is an alteration due to an external force. A strain gauge uses electrical resistance in order to quantify the amount of strain caused by an external force. There are several different types of strain gauges, the most common of which is a metallic strain gauge. This type of strain gauge is composed of a wire or small piece of metal foil. When a force is applied, the strain on the gauge is altered (either positively or negatively), resulting Microchip analog page Sample center microchipDIRECT Reference designs/ app notes Technical training 5 · PROjeCt ANAlOG · VOlUme 2 / NUmbeR 6 http://www.microchip.com http://www.microchip.com http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=79&redirects=analog http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=79&redirects=analog http://sample.microchip.com/Default.aspx?testCookies=true http://www.microchipdirect.com/catalogselection.aspx?returnURL=default.aspx http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1469&filter1=function&redirects=appnotes http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1469&filter1=function&redirects=appnotes http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1423

Table of Contents Feed for the Digital Edition of Project Analog - September 2008

Project Analog - September 2008 Contents Viewpoint About Project Analog Sponsor Selecting the Proper Amplifier for Strain Gauge Applications An Overview of Analog Sensor Conditioning Circuits Using a Digital Potentiometer to Optimize a Photo Detection Circuit Resistor Networks in Critical Applications Selecting the Right Op Amp Analog News Contact Microchip New Microchip Products Treelink MINDI™ Active Filter Designer Microchip Advanced Parts Selector (MAPS)

Project Analog - September 2008

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