CT04 Over-moulded Dry Reed Switch

The CT04 Series from Coto Technology is the smallest overmolded dry reed switch available on the market, engineered specifically for high-volume SMD applications requiring precision magnetic actuation, long operational life, and exceptional insulation performance. Designed as a single-pole, single-throw (SPST), normally open switch with ruthenium contacts, the CT04 delivers fast, clean switching and consistent reliability even in demanding environments. With its encapsulated overmolded package, the CT04 provides superior mechanical protection and insulation compared to traditional glass reed switches. The sealed, gas-filled internal contact structure ensures immunity to environmental contamination, oxidation, or corrosion—guaranteeing stable performance throughout the component’s operational life.

The CT04 supports activation via either a permanent magnet or an electromagnet, offering flexibility for design engineers. It retains the same PCB footprint as the well-established CT05 series but has been redesigned for efficient mass production, making it ideal for compact, high-volume assemblies. To support diverse SMT manufacturing requirements, the CT04 is available in Gull Wing and J-bend lead configurations, making it easy to integrate into automated pick-and-place and reflow processes. Every device undergoes 100% testing, including final magnetic sensitivity validation after lead forming to ensure absolute accuracy and repeatability.

Key Advantages of the Coto CT04 Series:

• Smallest molded reed switch available, enabling ultra-compact designs
• Hermetically sealed ruthenium contacts — no mechanical wear, oxidation or drift
• Tested to 1 billion+ operations, ensuring long-term reliability in mission-critical designs
• High insulation resistance and dielectric strength, far superior to Hall-effect or mechanical alternatives
• True dry reed technology — zero power consumption, ideal for battery-powered devices
• Available in SMD Gull Wing or J-bend formats, compatible with automated SMT assembly
• PCB footprint matches CT05 series, simplifying upgrades in existing designs

Typical Applications of the Coto CT04 Series Includes:

The CT04 is ideal for applications where space, precision, and long-term reliability are essential:

• Medical devices (hearing aids, infusion pumps, portable diagnostics)
• Proximity sensing / position detection
• Wearable and battery-powered devices
• Consumer electronics
• Industrial control and automation
• Security and tamper detection
• IoT sensors and low-power smart devices

Coto is a worldwide market leader of small signal-switching products sold into the Automatic Test Equipment, Data Acquisition, Instrumentation, Process Control, Telecommunications, Medical and Security markets. Coto specialises in the manufacture of relay, switch and sensor products. Coto are the pioneers of the RedRock® analog and digital TMR magnetic sensors, offering the lowest power consumption, highest sensitivity, ultra-miniature package size, short lead times and a highly-competitive price. Please visit https://cotorelay.com/ for more information.