What it shows
Alternating current in the primary coil makes a changing magnetic field in the iron core, which induces a voltage in the secondary coil (mutual induction). In an ideal transformer the voltages are in the same ratio as the numbers of turns.
This idea has a short entry only. For the science behind it, read the sentence above with your textbook and ask your teacher to explain the law or idea it shows, so you can describe it in your own words.
Materials
- A laminated iron core or a soft-iron ring
- Enamelled copper wire for two coils with different numbers of turns
- A low-voltage AC supply in the school lab
- An AC voltmeter or a small bulb
Safety
For this project: Never connect a home-made transformer to the mains. Use only a low-voltage AC supply, with your teacher.
Never use mains electricity: power models with cells, batteries or a low-voltage adapter. Sharp and hot tools, flames and lab chemicals need an adult or your teacher beside you. Keep magnets, button cells and small parts away from young children, and wash your hands after making.
How to go about it
Numbered steps have not been written for this idea yet. Plan it with your teacher: sketch the design with measurements, build one part at a time, test each part, and write every observation with the date. The free ebooks below have step-by-step projects of the same kind.
Free ebooks for this project
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