What Are Relays and How Do They Work

Since the advent of electronics, constant advancements to electronic components have significantly changed our capabilities of harnessing electrical current for various applications. Relays in particular are electromechanical devices that are present in numerous devices, providing an indispensable role for many systems. Despite their simplistic design, relays are capable of amplifying currents, controlling circuits, refreshing signals, and more. As such, understanding their functionality and the common types of relays available can be highly beneficial when operating with electronics.

At their most basic, relays operate as a remote switch that may provide on and off controls, limit current, or perform logic operations. With a sensing unit in the form of an electric coil, relays require AC or DC current in order to be actuated. When the current induced exceeds a specific value, the electric coil generates a magnetic force that causes an armature to either open or close contacts on the relay. From one circuit to the next, relays function to transfer a command from the control circuit to the load circuit. As the armature is attached to a spring, it may automatically return to its standard position when electricity ceases to flow through the relay, causing the contacts to return to their default positions as well. Depending on the function of the relay, various amounts of contact sets may be present. As relays provide operations for a number of electronic systems with varying needs, one can choose from common types such as reed relays, electromechanical relays, and solid state relays to accommodate system requirements.

Reed relays are a type in which a reed switch is placed within a solenoid, and contacts are guarded from corrosion with a glass tube that encapsulates them. For their operation, contacts are produced from magnetic materials so that when current is induced to the component, the magnetic force attracts the contacts so that they may move. As compared to other larger relay types, reed relays provide very quick operation and need little power from the control circuit for their functionality. Despite this, they are not capable of high switching current and voltage relay operations, and they may eventually become magnetized over time.

Electromechanical relays are one of the most simplistic and common types, and they utilize a magnetic field from a coil in order to move contacts. Within the realm of electromechanical relays, latching and non-latching types are available, each providing a different ability. With latching relays, one or two coils can remain in a set position when current is not flowing through the relay, and thus they are highly beneficial for systems in which low power consumption is desired. With non-latching relays, a spring or magnet is placed in order to maintain a set position for normally closed relays while there is no induced current.

The solid state relay is the last major type, and they function similarly to electromechanical relays despite having no moving components. Rather than using an armature and other electromechanical components, the solid state relay utilizes a thyristor, TRIAC, or another solid state switching component in lieu of a solenoid. If control circuits need to be isolated from the system, an optocoupler may also be used. Due to the fact that such relays do not use any moving parts, they provide high reliability and service lives that may be beneficial for a number of applications.

Whether you are in need of a power relay, relay switch, signal relay, or any other electrical component, ASAP Supply chain is your sourcing solution for all of your operational needs. As a premier online distributor, we offer our customers access to over 2 billion new, used, and obsolete components that cater to a variety of applications and industries. Explore our robust part catalogues at your leisure, and you may begin the purchasing process at any time by filling out and submitting an Instant RFQ form as provided through our website.