Series 20 – Episode 4 – Are reed relays a thing of the past?

This entry is part 7 of 31 in the series Electronic Specifier Insights

Paige Hookway speaks with Noman Hussain, Vice President of Software and Strategic Business Development, Pickering about the continued relevance and evolution of reed relay technology in modern electronic test systems.

Hussain argues that reed relays matter more now than ever because of the growing demands of test and measurement. Devices under test have more points that need testing, higher voltages and currents, and tighter accuracy requirements. Reed relays were once considered commodity parts, but modern applications make the detailed engineering around them crucial. Pickering has spent decades refining how to get maximum performance from what appears to be a simple, passive component.

Hussain explains what a reed relay is: fundamentally, a switch that routes a signal from one point to another, akin to a household light switch but used in test systems. In these systems, relays route signals between instruments and devices under test, managing thousands of signals under constraints such as voltage, current, and frequency. Although conceptually simple, this switching function underpins extremely complex test architectures.

Reed relays see use across a wide range of industries, including:

Semiconductor testing
Automotive and EV testing and charging infrastructure (onboard chargers and grid charging stations)
AI and GPU development, where many signals must be precisely switched for device validation
Oil and gas applications
Medical devices, such as defibrillators

Engineers choosing a switching technology typically prioritise signal integrity: they want the signal to traverse the switch without degradation from noise, added resistance, or capacitance, and they want multiple clean channels in a compact form factor.

Hussain explains that selecting the right relay often involves both data and experimentation. Engineers can request free relay samples and test data from Pickering, and the company’s experts review schematics with customers, advising on package size, voltage, and current ratings, relay placement, and driving best practices. While simulations help, real-world physical effects – temperature, environment, moisture, board layout – often force iterative prototyping and rapid design cycles. Pickering uses 3D printing to rapidly prototype relay packages before committing to final products.

A major misconception is that reed relays are interchangeable commodities that can simply be picked from a distributor catalogue. Hussain stresses this is dangerous, especially in safety‑critical applications. For example, choosing a relay without proper magnetic shielding and placing it next to another can cause unintended switching due to magnetic coupling. If that second relay controls a hazardous load, the result could be serious safety issues such as fire risk. Therefore, relay selection and system design must be done thoughtfully, especially in aerospace, automotive, and other life‑critical systems.

On current demand trends, Hussain sees the strongest pull from semiconductor, AI, and GPU markets, especially for high‑performance, high‑frequency relays in very small packages. He highlights a recently released 5 x 5mm SPDT, 2‑pole reed relay developed in direct response to a customer requiring many relays in a minimal footprint, while maintaining performance and mutual compatibility.

Hussain distinguishes between reinventing the relay and adapting to changing system requirements. Core test principles – checking voltage, current, frequency, and behaviour under temperature and altitude – remain the same, but package sizes, voltages, and frequencies are shifting. Much of the work involves evolving products to integrate into existing, heavily invested test systems, not discarding mature methodologies.

What keeps this domain interesting for Pickering is the constant stream of new customer applications: relays in satellites orbiting Earth thousands of times, in subsea oil refineries, in planes, and in cars. Each new use case presents fresh engineering challenges.

Hussain emphasises the importance of continuous refinement despite reed relays being a nearly 100‑year‑old technology. Pickering invests in new materials, structures, potting methods, and automation techniques to stay ahead in quality and innovation. As everyday products – from toasters to smart home devices – gain connectivity and electronics, the need for reliable testing grows. Test systems always require a source, a measurement element, and a switch, and reed relays remain central to that switching role.

He concludes that reed relays are far from obsolete. Demand is stronger than ever and likely to continue beyond his own career, as there is currently no clear replacement for their combination of performance, reliability, and flexibility in test systems. The future of advanced electronics, he suggests, still fundamentally relies on this ‘old’ but constantly evolving technology.

To hear more from Noman Hussain, you can listen to Electronic Specifier’s interview on Spotify or Apple podcasts.