Reed Switch Sensor

Reed Switch Sensor

Magnetic Contact Switch

The Reed Switch Sensor is a simple, reliable, and contactless magnetic sensing device that operates when exposed to a magnetic field. It consists of two ferromagnetic metal reeds sealed inside a hermetically sealed glass tube. When a magnet comes near the sensor, the reeds attract each other and close the circuit; when the magnet is removed, the circuit opens.

Because of its low power consumption, long life, and high reliability, the reed switch is widely used in electronics, automation, and security systems.

Key Features

• Magnetic Field Activated Switch

• Normally Open (NO) Contact Type

• No Physical Contact Required

• Very Low Power Consumption

• Fast Switching Speed

• Long Operational Life

• Compact and Lightweight Design

Working Principle

• In the absence of a magnetic field, the reed contacts remain open.

• When a magnet approaches, the metal reeds become magnetized and attract each other, closing the circuit.

• Removing the magnet causes the contacts to separate, opening the circuit again.

This contactless operation ensures minimal wear and high durability.

Technical Specifications (Typical)

• Switch Type: Normally Open (NO)

• Operating Voltage: Up to 100V DC / AC (model dependent)

• Switching Current: Up to 0.5A (typical)

• Contact Resistance: < 100 mΩ

• Response Time: < 1 ms

• Insulation Resistance: ≥ 100 MΩ

• Glass Tube Length: ~14–20 mm (varies by model)

Construction

• Glass Capsule:

  • Hermetically sealed

  • Protects contacts from dust and oxidation

• Ferromagnetic Contacts:

  • High sensitivity to magnetic fields

  • Long life with millions of operations

• Metal Leads:

  • Easy soldering and PCB mounting

Applications

• Door and window security systems

• Proximity detection

• Limit switches

• Speed and position sensing

• Smart home automation

• Automotive sensors

• IoT and embedded projects

• Educational electronics kits

Advantages

• No mechanical wear

• Silent operation

• High reliability

• Works in harsh environments

• Simple interface with microcontrollers