Compare two resistors in series
See this course’s project requirements
A simulation test report with labeled circuits, predictions, meter readings and an explained fault repair.
Keep your working files in your own notebook or software. Save a private description, checklist, and work link in My Proof.
What to include
- Three labeled circuit configurations with voltage, resistance and current units.
- Predicted and observed measurements with meter positions recorded.
- A series voltage-sum and parallel current-sum check.
- One open-branch fault with a single-change test and results.
- A report distinguishing simulation from physical measurement.
Review and revise
Use these criteria to check your work and choose what to improve.
- Connections match the intended series or parallel network.
- Arithmetic, signs and units are consistent.
- Fault diagnosis is supported by before/after evidence.
- The report states settings and model limits.
Want more background?
The idea in everyday life
Reset the workspace. Build one 9 V battery and two 10 ohm resistors end-to-end in a closed loop. Use ideal settings.
Series components share a path; their resistances add.
Compare two resistors in series — guided practice
Predict and measure one shared current and two voltage drops.
Reset the workspace. Build one 9 V battery and two 10 ohm resistors end-to-end in a closed loop. Use ideal settings.
1. Calculate first
Write total resistance 10+10=20 ohms. Divide 9 by 20.
You should see: Predicted loop current is 0.45 A.
The supply sees the sum of series resistances.
2. Build and measure
Connect the two resistors in a single path. Read current beside each resistor using the ammeter.
You should see: Both locations read approximately 0.45 A.
There is no branch where current can split.
3. Compare voltage drops
Measure across each 10 ohm resistor separately. Then add the two measured magnitudes.
You should see: Each drop is about 4.5 V; their sum is 9 V.
The supply voltage is distributed across the series components.
4. Change one resistor
Set the second resistor to 20 ohms. Predict total 30 ohms and current 0.3 A, then measure both drops.
You should see: The drops are about 3 V and 6 V; current is 0.3 A throughout.
Unequal series resistors have unequal drops at one shared current.
What to finish
A series comparison table with shared current and voltage sums.
Watch for this
Adding currents measured at different locations in the same path.
How can I tell I understand it?
Explain the result, reproduce the procedure, and complete the changed-input check.
Quick knowledge check
Answer all 3 questions. Get at least 2 right and the lesson completes automatically.
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Pass the check. We’ll save the progress.
Answer all 3 questions above and get at least 2 right. You can review the explanations and try again.
Go to the knowledge checkOptional course overview video · same video as Lesson 1
Building Series & Parallel Circuits with PhET Simulations
From Step by Step Science. Watch here or open it on YouTube .
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Source & access notes · checked 2026-09-12
Read substantive page text and examples.
Access: Public reading without a paid account; reviewed September 12, 2026.
Reuse: Link only. Lessons and practice assets are original; free access does not grant permission to copy the provider's material.
Source & access notes · checked 2026-09-12
Read substantive page text and examples.
Access: Public reading without a paid account; reviewed September 12, 2026.
Reuse: Link only. Lessons and practice assets are original; free access does not grant permission to copy the provider's material.
Source & access notes · checked 2026-09-12
Simulation landing shell and indexed component/measurement descriptions inspected; interactive execution not tested.
Access: Public reading without a paid account; reviewed September 12, 2026.
Reuse: Link to the hosted simulation; do not redistribute or embed the simulation without checking current PhET terms. Original diagrams and numerical fixtures supplied.
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