Latching Relays

A latching relay is similar in design and function to a standard general-purpose relay. However, there is one main difference with a latching relay, in that the latching relay will remain in the last position of which it was powered.

What is the difference between latching and non-latching relays?

Both types of relays in similar in design and function, however, a significant difference between them is that a latching relay will remain in the last position it when it was last powered, whereas a non-latching goes back to its normal position. This makes each more type of relay suitable for different applications.

Common Applications

Latching relays are used in a wide range of switching applications across many different types of environments and sectors. Some of the more common control circuits are telecommunication equipment, data processing equipment, alarms and security, measuring equipment and electronics designs.

Considerations when selecting a relay

When choosing a relay, it is important to consider a number of specifications to ensure it is fit for purpose, some factors include:

• Coil voltage - the required voltage to actuate the switching mechanism. If a voltage is too high this could damage the components, if it is too low then it will not actuate
• Contact configuration - This is the state the contacts are in without power. For example SPST, single pole single throw
• Contact material - the relay contacts are available in many materials that have certain properties. Common materials are gold, silver, tin oxide and nickel
• Coil power - the amount of power (watts) the coil operates at. This must match the power in the circuit for correct function
• Coil resistance - the amount of resistance (ohms) in the circuit that the coil creates