PCB prototyping boards are simple printed circuit boards, with a grid of several receptacles where electrical components can be placed and wired together in an organized fashion. These boards help reduce solder connections and the number of wires that need to be used to connect several different circuit components together.  They can provide power and ground bussing, thus providing an easy opportunity for multiple components to connect to the power bus if needed.

PCB prototyping boards are often used to prove a concept of an electrical circuit before a final product is sent for manufacturing. Often, electrical circuits can be very sensitive to different component values resulting in system performance variations, so it is important when designing a product to explore multiple scenarios of circuit performance. 

Using a PCB prototyping board allows for several different changes and iterations without the wasted development time and increased cost of having to redesign the printed circuit board.