Relays are essential components in the electrical and electronic systems used across various industries, from home appliances to complex industrial machinery. They allow for the control of high-power circuits with low-power signals, acting as an interface between control circuits and load circuits. To fully utilize the potential of relays, engineers rely on Relay Application Notes—technical documents that provide guidance on selecting and implementing relays in specific applications. These notes are invaluable resources for both novices and seasoned professionals. In this article, we will explore the key aspects covered in relay application notes and their significance in the design process.