LJ12A3-4-Z NPN DC Inductive Proximity Sensor Detection Switch

The LJ12A3-4-Z Inductive Proximity Sensor Switch is a reliable, metal-bodied detection switch designed for precise non-contact object detection. Whether you're building automation systems, CNC machines, robotics projects, or Arduino-based circuits, this sensor delivers consistent, accurate performance every time.

With a DC 6–36V operating range and NPN output, this proximity sensor is broadly compatible with microcontrollers, PLCs, and DIY electronics platforms. Its robust metal housing ensures long-lasting durability in workshop and industrial environments alike.

Key Features

Model: LJ12A3-4-Z/BX (NO) & LJ12A3-4-Z/BY (NC) — two output options available
Output Type: NPN (Normally Open / Normally Closed)
Operating Voltage: DC 6–36V
Detection Distance: 4mm
Barrel Diameter: 12mm
Housing Material: Durable metal construction
Non-contact sensing — no physical contact needed for reliable object detection
Arduino & PLC compatible — seamlessly integrates into DIY and professional automation setups
LED indicator — visual status confirmation for easy troubleshooting
Customizable: Available in 2 variants (BX Normally Open, BY Normally Closed)

Specifications

Sensing Distance: 4mm
Voltage: DC 6–36V
Output: NPN
Thread Diameter: M12
Body Material: Metal
Connection: 3-wire

What's Included

1 × LJ12A3-4-Z Inductive Proximity Sensor Switch (choice of BX or BY variant)

Perfect For

Arduino & Raspberry Pi automation projects
CNC machine tool position detection
Industrial conveyor and assembly line sensing
Robotics and motion control systems
DIY electronics and maker projects

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Frequently Asked Questions

Q: What is the LJ12A3-4-Z Inductive Proximity Sensor Switch used for?

A: The LJ12A3-4-Z is an inductive proximity sensor switch used for non-contact metal object detection. It is widely used in Arduino projects, CNC machines, robotic systems, PLCs, and industrial automation setups where precise, reliable position or presence sensing of metallic objects is needed.

Q: What is the difference between the BX and BY variants?

A: The LJ12A3-4-Z/BX is a Normally Open (NO) NPN sensor — its output is active (low signal) when a metal object is detected. The LJ12A3-4-Z/BY is a Normally Closed (NC) NPN sensor — its output switches off when a metal object enters the detection range. Choose the variant that matches your circuit's logic requirements.

Q: What voltage does this proximity sensor operate on?

A: This sensor operates on DC 6–36V, making it compatible with a wide range of power supplies including standard 12V and 24V systems commonly used in industrial and hobbyist automation applications.

Q: Is this sensor compatible with Arduino?

A: Yes! The LJ12A3-4-Z NPN proximity sensor is fully compatible with Arduino and similar microcontrollers. When using a 5V Arduino board, a simple voltage divider or logic level shifter is recommended on the signal line since the sensor operates at 6–36V.

Production & Packaging Notice

To maintain high stock availability and fast shipping times, our items are sourced from multiple verified manufacturing facilities. While the core quality, materials, and product specifications remain identical, you may notice slight variations in the packaging design, manufacturing origin, or the wording of the printed instructions.