Magnetic reed switches are electromechanical switching devices operated by an applied magnetic field. Comprising ferromagnetic contacts sealed in a glass envelope, they enable contact closure (or opening) without physical actuation. Their hermetically sealed design ensures reliability in harsh environments, making them critical components in modern automation, security systems, and industrial equipment.
| Type | Function | Application Example |
|---|---|---|
| Normally Open (NO) | Contacts open without magnetic field | Door/window sensors in alarm systems |
| Normally Closed (NC) | Contacts close without magnetic field | Emergency shut-off systems |
| Change-over (CO) | Three-contact configuration with common terminal | Industrial process control systems |
| High-Voltage Reed Switch | Rated for >1kV applications | Medical imaging equipment |
Typical structure includes:
Advanced variants feature sputtered ruthenium/tungsten coatings for improved contact durability.
| Parameter | Typical Range | Significance |
|---|---|---|
| Contact Rating | 10VA - 200VA | Determines switching capacity |
| Operate Time | 0.2 - 2.0ms | Response speed for fast-switching applications |
| Dielectric Strength | 100V - 10kV | Electrical insulation capability |
| Operational Life | 106 - 109 operations | Long-term reliability indicator |
| Actuation Distance | 1 - 50mm | Design flexibility for mechanical systems |
| Manufacturer | Product Series | Key Features |
|---|---|---|
| TE Connectivity | KB Series | 109 operations life, aerospace qualified |
| Omron | Reed Relays G6K | Subminiature size (10.5mm), 24VDC rating |
| Honeywell | 919H Series | High-voltage (3000VAC), medical-grade insulation |
| Hamlin | Hermetic Reed Switches | IP68 rating, -55 C to +125 C operating range |
Key considerations:
Case Study: Smart meter applications require reed switches with >108 operations life and anti-tamper certification.
Emerging developments include: