Where does the voltage go?
Choose equal resistors and inspect series. Predict each voltage drop before switching to parallel. What stays equal, and what changes?
DC circuits lab
Follow the current.
Keep the source and resistors the same. Change their connections, then compare where current flows and energy is transferred.
Series connection
Ideal · steady DC| Part | Resistance (Ω) | Voltage (V) | Current (A) | Power (W) |
|---|---|---|---|---|
| R1 | — | — | — | — |
| R2 | — | — | — | — |
Same parts. Compare both connections.
| Connection | Equivalent resistance (Ω) | Source current (A) | Source power (W) |
|---|---|---|---|
| Series | — | — | — |
| Parallel | — | — | — |
Displayed values are rounded to six significant figures. The CSV preserves unrounded values.
Ready when the values are.
Enter a source voltage and two resistances within the shown ranges. Both connections will update together.
Predict, change, explain.
Does the other branch notice?
Choose unequal resistors, select parallel and double R2. Watch R1’s current and the source current. Explain why they respond differently.
Account for every watt.
Add the two resistor powers in each connection. Compare the sum with source power. Then set the source to zero and describe what remains.
Take the next step
Twelve questions. Four connected ideas.
An original course on current, series connections, parallel connections and power, with worked explanations and transfer prompts. Read the course guide.
What this model assumes
An ideal source maintains its stated voltage. Wires have zero resistance. Both resistors are ohmic with fixed resistance, and the circuit is in steady state. This model does not calculate switching transients, temperature changes or component ratings.
Background: OpenStax, University Physics Volume 2, current, Ohm’s law, power and connections. Questions, explanations and diagrams here are original.