Stationary Currents Lab
Electrical Engineering I · Module 92315 · Chapter 2
Predict first, then watch. Commit to an answer and confidence rating before revealing how charge flow, material response, and energy transfer produce the result. Open any sandbox whenever you want to explore.
How the lab works
Choose a prediction, then say how sure you are. The reveal animates the mechanism and leaves your prediction beside the calculated result. Use Explore freely at any time to change the controls; your place in the challenges is kept.
Each experiment has four fixed challenges. After answering all four, its sandbox stays open and the lab records the skill on the course page.
2.1 Current flow: charge through a cut
Count charge per time, then tilt the cut to see why only the normal part of current density crosses a surface. A second control volume shows why stationary current has balanced inflow and outflow.
- Charge rate
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- Current through cut
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- Closed-surface net
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2.2.1–2.2.2 Drift and conductivity
See how electron drift points opposite the field while conventional current points with it. Carrier density and mobility set conductivity; the guide’s copper temperature model adjusts the response.
- Electron drift
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- Conductivity
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- Current density
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2.2.3 Uniform wire: geometry and resistance
Change the wire’s length and cross-section and watch resistance respond. Switch between a voltage source and a current source to see why the held-fixed quantity matters.
- Resistance
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- Current
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- Voltage drop
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2.2.4 Resistor tolerance: allowed values
A resistor’s printed value is nominal. Its tolerance sets an interval for the actual resistance; compare the E-series bands shown in the lecture.
- Allowed resistance
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- Actual value
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- Classification
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2.3 Conductivity interface: current bends
Split current density into normal and tangential parts. Normal current and tangential field stay continuous; conductivity changes the other components and turns the current direction.
- Jₙ (both sides)
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- Jₜ, side 1 → 2
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- Direction from normal
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2.4 Power and energy: where the work goes
Power is the rate of energy transfer. The resistor converts that energy to heat over time; local power density adds up across a volume to give total power.
- Electrical power
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- Power density
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- Energy after time
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Your results
Personal study lab based on the supplied Electrical Engineering I Chapter 2 lecture notes (WS 2026/27). Simulations use the guide’s formulas and material values; check exam-relevant details against the official course materials. Not an official FAU publication. Made by Thanate Amornjiraporn (Focus).