Test & Measurement

Tip of the Week: Measuring Resistance with Your DMM

April 13, 2015

The resistance measurement function of a digital multimeter can be used for electronics, instrumentation, controls, and many electrical applications.

Mark Lamendola

The DMM is arguably the most versatile electrical test instrument we have. Even the most basic model can measure voltage, current, and resistance. You can use the resistance measurement function for electronics, instrumentation, controls, and many electrical applications.

For example, what’s the value of a resistance thermal device (RTD) in ohms? Your DMM will tell you, but don’t forget to zero out your test leads. Some DMMs have a test lead zeroing feature; you clip the leads together and press the button, and the meter subtracts the lead resistance from the reading.

The typical DMM runs on a 9V battery. It’s not going to measure the 480V impedance across a connection. Use an AC resistance tester (impedance tester) to read the actual impedance or use a thermographic camera to see the heat loss across it.

Become familiar with the resistance measurement limitations of your DMM, and use it for the measurements it can take. For other resistance or impedance measurements, use a different instrument.

About the Author

Mark Lamendola

Mark is an expert in maintenance management, having racked up an impressive track record during his time working in the field. He also has extensive knowledge of, and practical expertise with, the National Electrical Code (NEC). Through his consulting business, he provides articles and training materials on electrical topics, specializing in making difficult subjects easy to understand and focusing on the practical aspects of electrical work.

Prior to starting his own business, Mark served as the Technical Editor on EC&M for six years, worked three years in nuclear maintenance, six years as a contract project engineer/project manager, three years as a systems engineer, and three years in plant maintenance management.

Mark earned an AAS degree from Rock Valley College, a BSEET from Columbia Pacific University, and an MBA from Lake Erie College. He’s also completed several related certifications over the years and even was formerly licensed as a Master Electrician. He is a Senior Member of the IEEE and past Chairman of the Kansas City Chapters of both the IEEE and the IEEE Computer Society. Mark also served as the program director for, a board member of, and webmaster of, the Midwest Chapter of the 7x24 Exchange. He has also held memberships with the following organizations: NETA, NFPA, International Association of Webmasters, and Institute of Certified Professional Managers.