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Measuring Electric Current

Experiment #19 from Physics Explorations and Projects

Education Level
High School


The purpose of this investigation is for students to learn how to measure current without direct instruction.

For the Preliminary Observations, demonstrate how to measure current in a simple circuit that consists of a power source, a current-measuring device, and one incandescent light bulb. Students will observe that bulb brightness increases as measured current increases.

Students experimentally determine how to use the current probe to accurately measure the current in a circuit with multiple light bulbs. The circuit will contain another current sensor and a “test” light bulb that will aid them in their observations.


  • Understand that ammeters must be connected in series with the circuit element where current is being measured.
  • Begin to develop the concept that “resistance” reduces current, that there is little resistance for current to flow through an ammeter, and that current has a tendency to flow along the path of least resistance.
  • Learn the conventions of “+” and “–” signs of electric current (if desired by the instructor).

Sensors and Equipment

This experiment features the following sensors and equipment. Additional equipment may be required.

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This experiment is #19 of Physics Explorations and Projects. The experiment in the book includes student instructions as well as instructor information for set up, helpful hints, and sample graphs and data.

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