LJ12A3-4-Z/BX Inductive Proximity Sensor NPN NO DC6-36V 4mm Range

This is a standard 3-wire DC sensor. Connect the brown wire to your positive DC supply voltage (6-36V), the blue wire to DC ground (0V), and the black wire is the NPN output. When a metal target is detected within 4mm, the black wire (output) will switch to ground (sink current). Always ensure a proper load (e.g., PLC input, relay coil) is connected between the black wire and the positive supply.

Yes, inductive proximity sensors like the LJ12A3-4-Z/BX can detect both ferrous (iron, steel) and non-ferrous metals (aluminum, copper, brass). However, the effective sensing distance may be reduced for non-ferrous metals compared to steel. For precise application, refer to the sensor's reduction factor, typically around 0.3 to 0.5 for aluminum, meaning the 4mm range may decrease to 1.2-2mm.

Yes, but an interface circuit is required due to the NPN output and higher operating voltage. The sensor's output can directly drive an optocoupler or a logic-level converter. For Arduino, connect the sensor's black output wire to a digital input pin via a pull-up resistor to 5V. When activated, the pin will be pulled low. Ensure your power supply for the sensor is within the 6-36V DC range, separate from the microcontroller's 5V rail.

NPN Normally Open (NO) means the output transistor is off (open circuit) when no target is present. When a metal object is detected, the transistor turns on, connecting the output wire to ground (sinking current). Normally Closed (NC) is the inverse: the output is grounded when idle and opens when a target is detected. Choose NO for applications where an active signal indicates target presence, which is the most common configuration for control logic.