Breadboard is a rectangular and perforated board. It is also called trainer board or projector board. It has two rows of holes at the top and two rows of holes at the bottom. Separately, the holes in each row are connected horizontally. The holes in the middle are divided into several vertical rows. The holes in a vertical row are connected vertically. One row of holes has no connection with the other row of holes. Again, there is no connection between the hole on one side of the empty space in the middle and the hole on the other side.