Testing communication relays with a multimeter is an essential skill for anyone working in electronics, electrical maintenance, or communication systems. Communication relays are crucial components in many devices and systems, serving as switches that open or close circuits depending on the conditions they detect. Ensuring that these relays function correctly can prevent system failures, especially in critical communication applications. In this article, we will guide you through the process of testing a communication relay using a multimeter.

Understanding Communication Relays Before diving into the testing process, it’s essential to understand the basic components of a communication relay. A typical relay has a coil that, when energized, causes the relay to activate and change the state of its contacts. These contacts include： Common (COM)： The common terminal, often the central point for other connections. Normally Open (NO)： A contact that is open when the relay is unpowered and closes when the relay is energized.

Normally Closed (NC)： A contact that is closed when the relay is unpowered and opens when the relay is energized.