This primary and secondary coil apparatus demonstrates the principle of Electromagnetic Induction and helps to explain the concept of a transformer. The Primary and Secondary coils are mounted on plastic spools with binding posts for easy connection. The primary coil slides inside the secondary coil. The set also includes a soft iron core for induction experiments. * Primary coil has 480 turns * Secondary coil has 3800 turns https://elecena.pl/product/27206016/rapid-primary-amp-secondary-coil-demonstrating-kit-electromagnetic-induction 2024-11-10 https://elecena.pl/product/27206016/rapid-primary-amp-secondary-coil-demonstrating-kit-electromagnetic-induction 2025-01-04 https://elecena.pl/product/27206016/rapid-primary-amp-secondary-coil-demonstrating-kit-electromagnetic-induction 2025-04-02 https://elecena.pl/product/27206016/rapid-primary-amp-secondary-coil-demonstrating-kit-electromagnetic-induction 2025-10-05