Relays are essential components in electrical and electronic systems, providing a means to control high-power circuits using low-power signals. These electromechanical switches are critical for automating various functions in numerous applications, including industrial control systems, automotive systems, home appliances, and more. Relays are categorized into different types based on their operating mechanisms, characteristics, and intended applications. In this article, we will explore the most common relay types, their working principles, and where they are typically used.