Simple electric circuit – measuring current and voltage
Integrated ScienceElectricity & MagnetismAges 13–14Virtual lab
Use it with your class: students open it from a link or a QR code, with no account needed.
Next in Electricity & Magnetism
A circuit with a battery, a switch, light bulbs, an ammeter wired in series and a voltmeter wired in parallel with a bulb. Flip the switch to open/close the circuit: electrons flow through the wires, the bulbs light up according to power, and the ammeter and voltmeter show readings; change the number of cells, the number of bulbs and the wiring (series/parallel) to compare I and U. Side scene: rub a plastic ruler on cloth and bring it near paper bits to see static electricity in action.
Lesson: Simple electric circuits; Current and voltage; Static electricity from friction
What it shows
A complete circuit lets charge flow from the battery through the bulbs and back; opening the switch breaks the loop and the current stops everywhere. The ammeter is connected in series to measure the current I, and the voltmeter in parallel to measure the voltage U across a bulb. In this model each cell gives 1.5 V and each bulb has a fixed resistance of about 8 Ω. Bulbs in series share the battery voltage, so current and brightness fall as more are added; in parallel every bulb receives the full voltage and the total current rises. A second scene shows charging by friction.
How to use
Start in the Circuit, measure I and U scene and read both meters with one bulb. Add bulbs, press Change wiring to switch between series and parallel, and compare the readings and brightness. Increase the Number of cells until a bulb is marked too bright because its 2.5 V rating is exceeded. Press Open / close switch to show the current dropping to zero. In the static scene, rub the ruler on the cloth, bring it near the paper bits, then press Discharge.
Parameters you can change
- Number of cells (1.5 V each) 1–4
- Number of bulbs (rated 2.5 V – 0.3 A) 1–3
- Bulb wiring Series, Parallel
- Switch closed at start
- Scene Circuit, measure I and U, Static electricity from friction
Questions to explore
- Why do three bulbs connected in series to two cells glow more dimly than a single bulb?
- What does the ammeter read when the switch is open, and why?
- When you add bulbs in parallel, how do the main-circuit current and the voltage across each bulb change?
