Induction-Coil-Ruhmkorff :- The primaries are wound with thicker copper enamelled covered wire on letherite pipe in two layers. The secondary coils are divided into two parts & are given heavy insulation. Each layer is wound in a cover of butter paper & are completing the winding, the entire is dipped into hot wax to seal each layer against moisture effect. The coils are housed in a teakwood base, voltage tested condensers are fitted inside the wooden polished base. Handles to get the spark are fitted on it & make or break points are of silver. One point is adjustable to get any cycle. On/off reversing switch commutator working on 6 to 12 V DC. Size – 10 mm, 25 mm, 50 mm, 75 mm, 100 mm.