Melde's Apparatus is a kind of apparatus that is specifically designed to reveal the effects of vibrations in a stretched cord. It is also used for investigating the relationship between frequency, tension and density. Melde's Apparatus is comprised of thin steel rod armature, which is mounted on a clamp formed by a pair of 4mm socket terminals, so that its free length can be adjusted as per the requirement. It can be served as a changeover switch. Melde's Apparatus is based on a sturdy box of size 150 x 80mm.