Diagnose a mismatch systematically
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
Use fictional test record F: 9 V source; intended two 10 ohm parallel resistors. Expected branches 0.9 A each, total 1.8 A. Observed: branch A0.9 A, branch B0 A, total 0.9 A. Branch B has a visibly disconnected return wire. Recreate this fault only in the simulator.
A fault hypothesis should explain the readings and predict the result of one change.
Diagnose a mismatch systematically — guided practice
Use a predicted-versus-observed record to identify a single fault.
Use fictional test record F: 9 V source; intended two 10 ohm parallel resistors. Expected branches 0.9 A each, total 1.8 A. Observed: branch A0.9 A, branch B0 A, total 0.9 A. Branch B has a visibly disconnected return wire. Recreate this fault only in the simulator.
1. Locate the disagreement
Copy expected and observed values into two columns. Mark branch B and total as different, branch A as matching.
You should see: The fault pattern is localized to branch B.
A localized mismatch suggests where to inspect first.
2. Name a hypothesis
Write: branch B return is open. Predict that reconnecting it restores 0.9 A in B and 1.8 A total.
You should see: The hypothesis has a specific predicted test result.
A useful explanation is testable.
3. Change one thing
Snap branch B’s return wire back to the negative node. Keep the battery and both resistor values unchanged. Measure B and total again.
You should see: B returns to about 0.9 A and total to 1.8 A.
Changing many values at once would obscure the cause.
4. Document the repair
Write the fault, evidence, changed connection and after-readings. If the prediction is not met, report that and inspect settings before inventing another explanation.
You should see: The record links one action to observed recovery.
Troubleshooting is an evidence trail, not a guess declared successful.
What to finish
A completed one-fault diagnostic log.
Watch for this
Changing multiple variables before measuring again.
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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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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