What Special Relays Are Most Common in Aerospace & Avionics Applications

Relays play a vital role across diverse aerospace and avionics systems, providing precise control over circuits even in the face of extreme operating conditions. In the environments typical of aerospace operations, conventional relays often prove insufficient due to the lack of performance and longevity that is necessary for more demanding operations. In this blog, we will explore some of the most notable types of special relays that find use in aerospace and avionics applications, highlighting their distinct features, advantages, and more.

What Is the Role of Relays in Aerospace and Avionics?

In aerospace systems, relays tend to function as electrically operated switches that allow low-power control signals to manage high-power loads with ease. This simple means of operation drives their use across flight control systems, power distribution networks, navigation equipment, and communication systems alike. Unlike consumer-grade options, the relays finding use in aerospace and avionics settings are expected to meet the following demands:

High reliability and endurance under vibration, shock, and temperature extremes
Low contact resistance to maintain efficient current transfer levels
Lightweight and compact construction to meet more strenuous aircraft weight limitations
Proper design and construction to ensure reliable operation in low-pressure or high-altitude environments

To meet these various expectations, engineers and operators take advantage of a variety of specialized relay types, each of which is tailored to address specific functions and environmental conditions.

Common Types of Aerospace and Avionics Relays

Hermetically Sealed Relays

Hermetically sealed relays are among the most widely used options for aerospace and avionics systems, these components being enclosed in airtight metal or glass housings that protect internal mechanisms from moisture, dust, and corrosive gasses. Key benefits include a long average service life and superior reliability across high-altitude environments and unpressurized compartments alike. With such features, one will find them in flight control systems, radar assemblies, power distribution panels, and other areas where long-term reliability and environmental resistance are top needs.

Solid-State Relays (SSRs)

Solid-State Relays (SSRs) have gained popularity in modern aircraft systems as a result of their ability to switch electrical loads without relying on any mechanical movement. Instead of traditional contacts, these devices employ semiconductor switching elements like thyristors, triacs, and transistors to carry out their duties. This leads to a number of notable benefits, including minimized wear, quieter operation, shock and vibration resistance, and more. The characteristics of SSRs make them suitable for assemblies like avionics computers, digital control systems, power management units, and more.

Latching Relays

Latching relays are designed to maintain an open or closed contact position after actuation, holding their configuration even when power is removed. This is achieved through a magnetic or mechanical locking mechanism, which allows them to conserve energy. These relays are also compact and feature ample shock and vibration resistance, making them useful for satellite systems, emergency control units, redundant power pathways, and other various systems.

Time-Delay Relays

Time-delay relays are a special type that adds a layer of sequencing and automation to aircraft electrical systems, specifically offering a programmed delay between actuation and circuit response for the staged startup or shutdown of connected equipment. This capability offers several advantages, including the prevention of electrical surges during power-up sequences, improved synchronization between multiple devices, and the automation of safety or redundant functions. Across aerospace operations, time-delay relays are most prevalent in engine ignition systems, hydraulic control circuits, cabin pressurization systems, and other assemblies.

Magnetic and Reed Relays

As the last forms of special relays we will discuss, magnetic and reed relays both use magnetic fields to open and close contacts, offering a balance between simplicity and reliability. Their lightweight and durable construction make them a dependable choice for avionics signal routing and low-power switching. They also offer a long mechanical life with reduced arcing, driving their use in navigation systems, communication radios, and instrumentation panels, where stable signal control is a major need.

Sourcing Aerospace and Avionics Relays

Given the critical nature of aerospace and avionics applications, selecting the right specialty relay requires careful consideration of environmental ratings, performance requirements, and compliance with industry standards. It is also essential to procure parts exclusively from trusted sources to ensure authenticity and performance reliability.

Secure Quality-Assured Relays from ASAP Purchasing

For those seeking the most reliable and cost-effective sourcing solutions for aerospace and avionic relays, there is no better procurement platform than ASAP Purchasing. Owned and operated by ASAP Semiconductor, this website offers access to a vast inventory of hermetically sealed relays, SSRs, latching relays, time-delay relays, and much more. With a commitment to rigorous quality assurance, competitive pricing, and rapid lead times, ASAP Purchasing ensures customers can fulfill their operational requirements without compromise. With this in mind, explore our selection today to discover dependable aerospace-grade relays and other electronic components that are tailored for the most demanding aviation applications.