Drawing equipotential and electric field lines is an activity commonly found in most second-semester introductory physics courses. Unfortunately, current commercial lab offerings are expensive and do not afford the opportunity for real-time graphical visualization of the trends in voltage in different regions. In this brief article, we describe a flexible alternative that utilizes the Interactive Online Lab (IOLab) device and easy-to-acquire supplies to create an experiment that yields robust results and has resulted in a positive response from our students.

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The IOLab is capable of outputting 3 V or 3.3 V and can measure voltages up to 3.3 V. We’ve found that just 3 V across parallel bars is sufficient to create a clear and measurable pattern of equipotential lines.
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A model for open-ended “
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