Invented by Bell Telephone Laboratories in 1936, the reed relay has evolved from being very large with crude parts to being a much smaller and extremely dependable component over time. In this blog, we will discuss what solid-state relays and electromechanical relays are, what exactly MEMS switches do, and what the future of reed relays is.
Electromechanical relays, or EMRs, are extensively used as a switching technology. They are also the most cost-friendly relay solution available. Manufacturers of this technology have heavily invested in equipment that allows for electromechanical relays to be produced in bulk, driving down their overall cost.
Electromechanical relays are assembled in plastic packages that provide them with some amount of protection. However, over time, the contacts will become prone to oxygen, sulfur ingress, plastic body emissions, and external pollutants. As compared to reed relays, EMRs have a shorter mechanical life because of the presence of moving parts that are absent in reed relays.
Electromagnetic relays are structured to accommodate a wiping action when the contacts close. This helps in breaking small welds and also allows relays to self-clean their contacts which leads to higher contact ratings. On the other hand, it may also increase wear and tear on the contact plating.
Solid-state relays are a switching technology that is based on semiconductor devices. The leakage current of these relays is associated with their semiconductor lineage, and as a result, they have low insulation resistance. Unlike reed relays, solid-state relays are not isolated from the signal path by the coil. Hence, an isolated drive needs to be implemented in the relay. Solid-state relays have high power ratings and their operational speed is also fast.
What Are MEMS Switches?
Forged on silicon substrates, MEMS switches are a type that are still within the development stage for general use. The silicon substrate comprises a three-dimensional structure that is micro-machined with the help of certain semiconductor processing techniques for creating a relay switch contact. After this, the contact is then deflected using either an electrostatic field or a magnetic field. It is also possible to fabricate a MEMS switch so that its switch is hermetically sealed at the silicon level or in a ceramic package.
It must be noted that fabricating the switch may lead to frequent switching characteristics at low signal levels. However, MEMS switches comprise small contact areas and fewer operating forces, and this might cause limited hot-switch capacity and partial weld problems.
The Future of Reed Relays
In the past few years, there has been an increasing focus on miniaturization. Dealing with small parts has always required more sophisticated and efficient technology and methods for creating the glass-to-metal hermetic seal. There also has been drastic developments in contact plating materials and methods, particularly in terms of the purity of materials, cleanliness, and the reduction of organic contamination or microscopic foreign particles, which has led to a great low-level performance.
In credit to the constant advancements in coin-winding techniques, reed-relay operating coils are now much smaller and more powerful. A reed relay is an almost perfect switching element that has a simple metallic part. It is definitely here to stay for many years to come.
Just Connectors is a platform owned and operated by the ASAP brand, which was formed to optimize the purchasing process of defense, aviation, and marine industries. We are a one-stop-shop offering our customers purchasing solutions to simplify procurement. We offer a solution with an inventory of over 2 billion new and obsolete verified parts manufactured by trusted manufacturers. We are one of the top distributors with AS9120B, ISO 9001:2015, and FAA AC 100-56B accreditation. We serve with the commitment of providing top-quality and reliable products and maintain a no-China sourcing pledge on all parts and components. Our reed relays are used in many industries for military and civilian applications. If you want to buy reed relays, feel free to reach out to Just Connectors.
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