Charge flow and current sim
Close the switch on a real series loop and watch the lamp light at once while every ammeter reads the same; drag a magnifier over any lead to see the electrons drift from − to + against the conventional current, time a run, work out Q = I × t yourself (✗ reasons for mA and ms) and check it against a coulomb counter.
Electric circuits: charge, current and Q = It · covers the O-Level, IGCSE, GCSE topic
What the sim shows
Model. Every current comes from one nodal-analysis solver shared by the circuit figures. Two cells: 1.5 V and 0.3 Ω each (chosen). Lamp: 3.5 V 0.3 A, so 11.67 Ω hot, with a filament whose resistance rises with its p.d. (a chosen simple law, beyond the syllabus). Rheostat 0 to 20 Ω in 0.5 Ω steps; each ammeter and the counter 0.1 Ω, each lead 0.01 Ω (chosen). Steady d.c.: the lamp heats at once and the cells do not run down. The timer runs exactly while the switch is closed (wired to a second contact on the switch); the counter adds up I × time. The close-up shows only the electrons' slow average drift, at its true speed for that scale; their fast random motion is left out, and the dots and ions are not drawn to scale.
- The magnifier: drag it over a lead to see inside
- Two cells, ammeters A1–A3, switch, timer, lamp, rheostat, coulomb counter
Use it in your lessons
- Try it here: anyone can unlock 2 figures free, and a free account unlocks up to 5. Runs on a laptop, a Chromebook or a phone; nothing to install.
- Present it and share student links with the teacher plan, from US$5 a month, billed yearly.
- Put it on your own website or LMS for US$9, paid once, or every sim from US$29 a month.
Free guide: 12 practicals as sims, and how to run one in a lesson →
Need a version for your exact set-up? Have one made: US$49 a figure in an order of 5.
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