Using ammeters and voltmeters sim
Drag the meters' plugs onto a real bench circuit: put the ammeter in series and the voltmeter across the lamp, red to +, see what really happens when they are wired wrongly (a blown fuse, a dark lamp), pick the range, read the needle to half a division looking straight on, correct a zero error, compare a digital display, and work out the lamp's resistance from your own readings.
Electric circuits: measuring current and p.d. · covers the O-Level, IGCSE, GCSE topic
What the sim shows
Model. Every current and p.d. comes from one nodal-analysis solver shared by the circuit figures. Supply: 0 to 12 V in 1 V steps with an internal resistance of 0.5 Ω (chosen). Lamp: 12 V 6 W, so 24 Ω hot; its filament's resistance rises with the p.d. as R = 24 × (V ÷ 12)^0.4, never below 2.4 Ω (a chosen simple law, beyond the syllabus). Each lead 0.01 Ω. Meters: the resistances in the table (chosen); fuses 6 A (analogue), 2 A and 10 A (digital). Parallax: the needle 3 mm in front of a 45 mm, 90° scale, the eye 25° to one side (chosen). Zero errors are needle offsets of 2 % or 3 % of full scale (chosen). Everything is steady d.c.: the lamp heats at once, nothing drifts, and the supply holds its setting.
- The plug you are moving (pick another with 1–6)
- Power supply, knife switch, lamp on a board, link lead, ammeter, voltmeter, spare fuses
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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