Reed Switch

  • AMP-X163
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Sleep well while this magnetic sensor guards your shop, warehouse, or home.

Principles of Operation

This magnetic detector consists of a master element and a reed switch:

  • The driver is a magnet in a plastic case.
  • Reed switch is an electromechanical switching device, changing its state when exposed to a magnetic field.

When both elements are at a distance greater than 45 millimeters (1.8”), the reed switch contacts are open. When they are at or closer than 10 millimeters (0.4”), they are closed. Between them is the “gray zone”. Each reed switch has a trigger threshold in this range, but where it is, you will have to find out yourself.


It is convenient to connect the module to an Arduino or Iskra via this Troyka pull up. When turned on, the module will give a "high" signal, and when you bring the magnet closer it will give a "low" signal.

You don't even need a microcontroller to make an alarm. Assemble the magnetic detector, siren, relay, and power supply into one circuit. With that your alarm is ready. When the door or window opens, the siren will scare off the intruder. Reed switches can be connected in a chain and when at least one of them is triggered the siren can't be turned off.

Package Contents

  • 1 × Magnetic Sensor - Reed Switch
  • 1 × Driving Element - Magnet

Dimensional Drawing

Dimension Drawing


  • Type of Reed Switch: Normally Open
  • Switched Voltage: 0.05–72 V
  • Switched Current: 0.1–250 mA
  • Maximum Switching Power: 10 W
  • Contant Closing Distance: ≤ 10 mm (0.4”)
  • Contact Opening Distance: ≥ 45 mm (1.8”)
  • Output Electrical Resistance with Closed Contacts: 0.5 Ω
  • Output Electrical Resistance with Open Contacts: 200 kΩ
  • Tested for: > 1,000,000 switches