If this is your question and my answer is as below.

Gadget can be defined as a small special device which is particularly manufactured for a special task or special purpose. And another question that may rise in your mind when you think of the gadgets is  “What is Gizmos?”  Gizmos is nothing but a gadget.

There are two categories in the gadget,

1. Mechanical Gadget
2. Electronic Gadget

Mechanical Gadgets are those that are actually devices that operate mechanically like bicycles, key watches and clocks etc.

Electronic Gadgets are those tat does not require any description as every one in this world would be using an electronic gadget . These include gadgets like calculator, electronic watches, mobile phones and laptops etc.