Reed Relays What it is A reed relay is a compact electromechanical switch that uses a magnetically actuated pair of hermetically sealed reed contacts inside a coil. When the coil is energized, the contacts close (or open), providing reliable switching with electrical isolation between the coil drive and the switched circuit. Key benefits — why you need it High isolation and signal integrity: The physical separation between coil and contacts provides galvanic isolation, reducing interference and protecting sensitive circuits. Low drive power and compact footprint: Requires minimal coil power and occupies little board space, making it suitable for battery-powered and space-constrained designs. Long life and stable contact performance: Glass-sealed contacts limit contamination and wear, giving consistent, repeatable switching over many cycles. Fast, clean switching for low-level signals: Ideal for switching small currents and voltages with low contact resistance and minimal bounce. Important attributes Function: Magnetic actuation of sealed reed contacts via an external coil; can be used for both make and break switching functions in low-power circuits. Compatibility: Works with standard low-voltage driver circuits and integrates easily into PCB or wiring harness designs that require isolated switching. Suitable for analog and digital signal paths where low leakage and low contact resistance matter. Size and packaging: Small, lightweight form factor; reed relays are available in compact packages that minimize PCB area and reduce parasitic capacitance compared with larger mechanical relays. Materials and construction: Typically glass-sealed reed contacts inside a protective housing; the sealed construction minimizes oxidation and contamination for dependable contact performance. Performance characteristics: Low contact resistance and leakage, fast switching response, and high repeatability. Performance favors low-current and low-voltage applications where clean, isolated switching is required. Practical use scenarios Test and measurement equipment: Multiplexing low-level signals in data acquisition systems, precision DVMs, and automated test fixtures where low leakage and repeatable contacts preserve measurement accuracy. Telecom and communications switching: Routing analog or digital lines in switching matrices, protection circuits, or line sensing where isolation and compact packaging are required. Security, sensing, and medical devices: Detecting open/closed events, switching sensor inputs, or routing low-current diagnostic signals in compact, low-power devices where reliability and cleanliness of the contact are critical. Why choose reed relays for your design When you need isolated, low-power switching with high signal integrity and long-term reliability, reed relays provide a simple, proven solution that minimizes board space and simplifies electrical isolation. They are particularly valuable in applications that handle low-level signals or require minimal contact degradation over many cycles.