In earlier times, electronic device circuits were used. However, they had a number of significant disadvantages. To start off with, they required way more space than an integrated circuit. Secondly, each of their components had to be adhered to the circuit not just individually, but individually through the process of soldering making their reliability aspect quite poor. Furthermore, it was extremely hard to change the components of the system, meaning that one failed component in the circuit required the entire circuit board to be changed. To overcome these problems of the circuit board, integrated circuits were developed. https://pcblayoutdesigner.weebly.com/blog/what-are-pcb-circuits-and-how-do-they-help