For studying electromagnetic induction, ferromagnetizm and principles of a transformer. Consists of two coils wound with enamelled copper wire over heavy plastic spools ﬁtting one within the other. The inner primary coil has 1250 turns of heavy wire and the outer, acting as secondary coil with 250 turns of ﬁne wires. Square supports of thick insulating material are used as vertical or horizontal mount. Both coils are equipped with binding posts and a soft iron core for induction studies.