understanding relay characteristics： key features and applications

Relays are widely used in various electrical and electronic systems to control the switching of circuits. They are devices that use a low-power electrical signal to control the switching of a higher-power circuit. The fundamental characteristic of a relay is its ability to control a large current with a smaller control signal. Understanding the key characteristics of relays is crucial for selecting the right relay for specific applications. In this article, we will explore the essential relay characteristics that determine their functionality and performance.

1. Coil Voltage and Current The coil voltage is one of the most critical characteristics of a relay. It refers to the voltage applied to the coil of the relay to activate the switching mechanism. Common coil voltages include 5V, 12V, and 24V, although relays can be designed to work with various voltages, depending on the application. The coil current is the current needed to energize the coil, which is also an essential factor to consider, as it determines the power consumption of the relay during operation. 2. Contact Type Relays typically have two types of contact configurations： Normally Open (NO) and Normally Closed (NC). The Normally Open (NO) contact remains open (disconnected) when the relay is not energized. When the relay is activated, the contact closes, allowing current to flow through the circuit. On the other hand, Normally Closed (NC) contacts are closed (connected) when the relay is not energized, and they open when the relay is activated. Some relays also come with changeover (CO) contacts, which allow for switching between NO and NC contacts depending on the relay’s activation.