How To Make Sense Of Sense Resistors

Focus:

This article is a mini-tutorial on fundamental concepts for power-circuit design involving sense resistors. It discusses the problems that must be understood to obtain accurate measurements with sense resistors including temperature effects, properties of resistor materials, make-versus-buy options, and Kelvin sensing. More-detailed discussions follow on how to measure resistor parasitics. Two methods for measuring the parasitic series inductance of sensor resistors—frequency sweep and pulse-response methods—are explained to enable designers to properly evaluate and characterize sense resistors for use in power supply circuits. These methods employ an oscilloscope, sine and square-wave generators, and basic probing accessories. Discussions note practical or typical values of the parameters discussed.

What you’ll learn:

• How to obtain accurate measurements when using sense resistors in power supply circuits
• How to measure the parasitic inductance of sense resistors using either the frequency sweep or pulse-response methods
• How to make sense resistors using manganin wire

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Author & Publication:

Dennis Feucht, Innovatia Laboratories, Cayo, Belize, How2Power Today, Apr 15 2020

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