Prototype PCBs are frequently used in prototype development to test and validate new designs before mass production. They often consist of standard materials like FR4 or CEM1 and offer a cost-effective solution for quickly creating circuit patterns. These circuit boards are typically simpler in construction and have a low layer count (often single- or double-sided), making them an ideal choice for initial test runs and rapid iterations. They are primarily used in research and development to quickly validate design concepts and test changes before more complex production versions are developed.