Reading Between the Lines, Using data sheets correctly when selecting resistors

Focus:

This article explains how to select a resistor for measuring current, discussing the application and resistor parameters that need to be considered, providing advice on interpreting resistor data sheets, and providing example calculations. After explaining the basics of current measurement, the article discusses the factors that influence the accuracy of the current-sense signal. Next, there’s an example of how to calculate resistance and power rating, followed by discussion on layout considerations and long term stability (i.e. drift in resistance value). The article concludes with some comments on design tradeoffs. There’s some discussion of the vendor’s resistors and their advantages, but most of the discussion applies to resistors in general.

What you’ll learn:

• How to select a resistor for current sensing

Notes:

I first read this article in Bodo’s Power Systems, January 2016, pages 22-25, but then discovered an earlier version published in EE Times Europe, October 27, 2015. The link provided here is for the version posted on the vendor’s website. The publication date listed here corresponds to Bodo’s article.—David Morrison, Editor, How2Power.com

View the Source

Author & Publication:

Thomas Otto, Isabellenhutte, Vendor website, Jan 01 2016

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