CENCO® AP Physics Lab 2.10: Time Constant of an RC Circuit

Determine the time constant of an RC circuit, and calculate the resistance of an unknown resistor.

Introducing the new CENCO AP Physics lab series!

Ideal for AP Physics 1 and 2, AP Physics C, IB DP Physics, and advanced/honors physics courses, each of the 35 experiments is aligned with the revised College Board AP curriculum. These innovative labs go way beyond traditional exercises, turning real-world scenarios into true guided-inquiry investigations. Students are given a goal, but the investigation is driven by their ideas. As they draw conclusions, students report their results using the Claim-Evidence-Reasoning model. The teacher guides and student manuals are authored and reviewed by AP Physics teachers with decades of combined experience, so you can trust the setups to be successful in your classroom. All labs come complete with instructions and materials for one lab group of 2 to 4 students. For your convenience, labs are packaged to allow you to purchase only what is required for each experiment.

In this investigation, students will construct a voltage decay curve by charging a capacitor and then allowing it to discharge through an unknown resistor. By linearizing the graph and some simple algebra, they can calculate the value of the resistor. A cool bonus: students learn about solderless breadboards.