Compare parallel branches
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. Use a 9 V battery and two branches: one 10 ohm resistor, one 20 ohm resistor. Each branch connects directly between the same supply nodes.
Parallel branches connect to the same two nodes, so they share voltage.
Compare parallel branches — guided practice
Predict branch currents and check their sum.
Reset. Use a 9 V battery and two branches: one 10 ohm resistor, one 20 ohm resistor. Each branch connects directly between the same supply nodes.
1. Draw two paths
Sketch positive and negative supply nodes. Draw the 10 ohm path and 20 ohm path separately between those nodes. Recreate this in the simulator.
You should see: There are two complete paths from positive to negative.
A branch is defined by connections, not where it sits on screen.
2. Predict each branch
Calculate 9/10 and 9/20. Record predicted branch currents.
You should see: Predictions are 0.9 A and 0.45 A.
Both resistors receive the full 9 V.
3. Measure branch and total
Measure each resistor voltage and each branch current. Measure total current in the supply wire before the split.
You should see: Both drops are about 9 V; supply current is about 1.35 A.
At a node, incoming current equals total outgoing current.
4. Open one branch
Disconnect only the 20 ohm branch. Keep the 10 ohm path intact, then measure again.
You should see: The 10 ohm branch remains about 0.9 A; total falls to 0.9 A in the ideal model.
A working alternate path can continue when one branch is open.
What to finish
A parallel-branch diagram and checked current balance.
Watch for this
Assuming equal voltage means equal current.
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 .
Optional course overview. Follow the written steps below at your own pace.Tools, templates, and lesson sources
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Sources and further reading
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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
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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