Why Do We Use Reed Switches
Switches serve as drawbridges in electric circuits. When the switch is closed, the “bridge” is down, allowing electric current to flow around the circuit. Similarly, if the switch is opened, the “bridge” is up and no current flows. Essentially, they function to activate or deactivate a circuit at any given time.
In particular, reed switches, or reed relays, are a special type of electrical switch that can be actuated by a magnet. They feature thin, flexible, ferromagnetic metal wires or blades called reeds that are positioned a short distance apart in a hermetically sealed glass bubble. The reeds are typically coated with a hard wearing metal such as rhodium or ruthenium.
Within the envelope, there is an unreactive gas like nitrogen to keep the reed free of dust and dirt. Moreover, the glass is often equipped with an outer casing of plastic for even greater protection. Meanwhile, the contacts are made from a nickel-iron alloy that is easy to magnetize.
In a majority of other switch types, contacts are opened or closed by physically maneuvering a part of the switch in order to make or break the electrical circuit. Common examples of these types include push-button, momentary, or rocker switches. With reed switches, this is not the case. Rather, they rely on magnetic forces to move their contacts together or apart.
Depending on the reed switch type, the proximity to a magnetic field either opens or closes a small air gap between the two metal blades. In simple models, this can be achieved by moving a reed switch magnet closer or further away from the glass envelope containing the reeds. It is important to note that while most reed switches have two ferromagnetic contacts, some have one contact that is ferromagnetic and one that is non-magnetic.
Reed switches find use in a wide range of applications, some of which include everyday examples. For instance, laptops and mobile phones make use of reed switches, allowing device screens to power off when the lid is closed. Similarly, automatic doors with proximity sensors, tamper-proofing systems, anemometers, and more. They are often used for their low power consumption, reduced potential for electrical interference, compact design, and low price points.
NSN Parts Hub is a leading distributor of reed switches, all of which have been subjected to varying levels of quality assurance measures, tests, verifications, and assessments. With over 2 billion items in our inventory, sourcing all that you need for your operations is quick and easy. Initiate the procurement process with a competitive quote which you can access via our Instant RFQ service and see how NSN Parts Hub can serve as your go-to sourcing solution today!