A simple electric circuit containing a battery, a switch, and an electric motor. When a caller pressed the switch, the battery fed power to the motor and made it spin around and hit on the semispherical iron shell, thus producing the sound.
The first electric doorbell was invented by Joseph Henry in 1831. At the time, many homes did not have electricity. So early doorbells were sold with their own attached wires and batteries. The first wireless doorbells worked on a radio transmitter.
An electric bell contains an electromagnet, consisting of coils of insulated wire wound round iron rods. When an electric current flows through the coils, the rods become magnetic and attract a piece of iron attached to a clapper. The clapper hits the bell and makes it ring.
|Dimensions||12 x 11 x 3 cm|
|Each Project Kit Contains||
1. Material required for doing activity
2. Basic Material required for decoration
3. Detail Instruction to build models.
1. Minimum Recommended age: 9+
2. Material Type: Raw Material
3. Mode of use; Do It Yourself (DIY), Build from scratch
4. Time required: 30 min
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