What it does
An electric bell has no motor. It rings because of a clever loop. When you press the switch, current flows through a coil wrapped on an iron core, and the core becomes an electromagnet. It pulls a springy iron armature, and a small hammer on the armature hits the gong. But as the armature moves, it leaves the contact screw, which breaks the circuit. The current stops, the electromagnet switches off, the spring pulls the armature back, the contact closes again and the whole thing repeats, many times a second.
This page animates that cycle. The contact between the armature and the screw glows when the circuit is closed, and the coil lights up when the electromagnet is on. It follows the Class 8 Science topic on the effects of electric current. To build the magnet yourself, try the electromagnet builder, and to see how a switch and a battery make a circuit, use the simple circuit lab.
How to use it
- Watch the animation, or press Pause to stop it.
- Read the line under the picture; it says whether the circuit is closed or open.
- Slide the Current to change how fast the bell rings.
What each setting does
- Current: more current makes the electromagnet stronger and the cycle faster. In this model the bell rings 5 times a second for every ampere. At 0 A there is no magnet, so no ring.
- Pause / Play: freezes the picture so you can study one moment.
Worked example
At 1.5 A the model gives 5 × 1.5 = 7.5 rings per second, so one ring takes 1 ÷ 7.5, about 0.13 seconds. Slow down to 0.5 A and you get 2.5 rings per second.
FAQs
Why does the circuit have to break? If it stayed closed, the electromagnet would keep the armature stuck against it, and the hammer would hit the gong only once.
Why is the armature made of iron? Iron is attracted by a magnet and switches easily, while the core loses most of its magnetism when the current stops.
Are the numbers real? No. The ring rate is a rounded teaching value, and the picture is simplified.
Where the numbers come from
- How an electric bell works (electromagnet, iron armature, spring, contact screw, make-and-break circuit): standard school physics. The ring rate of 5 rings per second for every ampere is a rounded, made-up teaching value. Drawings are fibub's own.
Standard scientific values, such as constants, atomic weights and melting points, are facts found in every textbook; we name where ours were checked. If you are an author or publisher and want a value, a credit or a table changed or removed, tell us and we will act quickly.
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Last updated 2026-11-10.