It consists of circular frame made from non- magnetic silver aluminium alloy. An insulating copper wire wound on a frame. The ends of the wires are connected to the terminals, which are fitted on the superior quality wooden board. A rectangular frame is supported on wooden board Anodized aluminium rods are graduated upto 50cms on both sides. Superior quality permanent magnet compass box moves in a platform. This plat from moves on the rectangular frame along the axis of coil. The compass is no arranged that center of the magnetic needle lies on the axis of the coil with compass box.