{"product_id":"lj12a3-4-z-by-pnp-npn-metal-inductive-proximity-switch-4mm","title":"LJ12A3-4-Z\/BY PNP NPN Inductive Proximity Switch 4mm Sensing","description":"\n\u003ch2\u003eLJ12A3-4-Z\/BY Metal Inductive Proximity Switch — PNP \u0026amp; NPN, 4mm Sensing Range\u003c\/h2\u003e\n\u003cp\u003eUpgrade your automation setup with the \u003cstrong\u003eLJ12A3-4-Z\/BY Inductive Proximity Switch\u003c\/strong\u003e. This compact, cylindrical metal sensor delivers reliable, contactless detection of metallic objects with a precise \u003cstrong\u003e4mm sensing distance\u003c\/strong\u003e. Available in both \u003cstrong\u003eNPN (LJ12A3-4-Z\/BX)\u003c\/strong\u003e and \u003cstrong\u003ePNP (LJ12A3-4-Z\/BY)\u003c\/strong\u003e output configurations, it integrates seamlessly into CNC machines, robotic arms, conveyor systems, 3D printers, and other industrial or DIY automation projects.\u003c\/p\u003e\n\n\u003cp\u003eMade in Mainland China.\u003c\/p\u003e\n\n\u003ch3\u003eKey Features\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003e4mm Sensing Range:\u003c\/strong\u003e Accurate, consistent detection of metallic targets without physical contact.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eDual Output Options:\u003c\/strong\u003e NPN (sinking) and PNP (sourcing) variants to match your controller's input requirements.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMetal Housing:\u003c\/strong\u003e Durable construction designed to withstand industrial environments, vibration, and daily wear.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eLow Voltage Compatible:\u003c\/strong\u003e Operates safely below 50V AC or 75V DC (EU LVD compliant).\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eEasy Installation:\u003c\/strong\u003e Standard M12 cylindrical body with threaded barrel fits most standard mounting brackets.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eWide Application:\u003c\/strong\u003e Ideal for robotic arms, CNC homing\/limit sensing, 3D printer endstops, conveyor lines, and position detection.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eNo High-Concern Chemicals:\u003c\/strong\u003e Clean and safe material composition.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eSpecifications\u003c\/h3\u003e\n\u003ctable\u003e\n  \u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eModel\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eLJ12A3-4-Z\/BX (NPN) \/ LJ12A3-4-Z\/BY (PNP)\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eSensing Distance\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e4mm\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eHousing Material\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eMetal (M12 Cylindrical)\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eOutput Type\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eNPN \/ PNP\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eOperating Voltage\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eBelow 50V AC or 75V DC\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003ePackage\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e1 x Inductive Proximity Switch\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eCountry of Origin\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eMainland China\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\n\n\u003ch3\u003eWhat's in the Box?\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e1 × LJ12A3-4-Z\/BY PNP or NPN Metal Inductive Proximity Switch\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003e\u003cem\u003eNote: Color may vary slightly due to monitor display differences. Manual measurement tolerances are normal and expected.\u003c\/em\u003e\u003c\/p\u003e\n\n\u003ch3\u003eRelated Products You May Like\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\u003ca href=\"\/products\/1pc-10g-high-grade-silicon-grease-lubricant-o-lubrication-good-odorless-smoothness-for-o-rings-tube-silicone-grease-lubricant\"\u003e1PC 10g High Grade Silicon Grease Lubricant for O-Rings \u0026amp; Mechanical Parts\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"\/products\/3pcs-silicone-sealant-scraper-set-multi-functional-caulking-nozzle-tools-for-tile-floor-joints-grout-finishing-and-renovation\"\u003e3PCS Silicone Sealant Scraper Set – Multi-Functional Caulking Tools\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"\/products\/1pc-multi-use-faucet-bubbler-wrenches-6-sizes-sink-wrenches-detach-tool-for-kitchen-bathroom-faucet-parts-repair-spanner\"\u003e1PC Multi-Use Faucet Bubbler Wrenches – 6 Sizes Spanner Tool\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eLearn more: \u003ca href=\"https:\/\/www.osha.gov\/personal-protective-equipment\" target=\"_blank\" rel=\"noopener\"\u003eOSHA on personal protective equipment\u003c\/a\u003e\u003c\/p\u003e\n\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\n\u003ch4\u003eQ: What is the difference between the NPN and PNP versions of the LJ12A3-4-Z proximity switch?\u003c\/h4\u003e\n\u003cp\u003eA: The NPN version (LJ12A3-4-Z\/BX) outputs a sinking signal — the output wire pulls LOW (to ground) when an object is detected, commonly used with PLCs and microcontrollers that accept NPN inputs. The PNP version (LJ12A3-4-Z\/BY) outputs a sourcing signal — the output wire pulls HIGH (to supply voltage) when activated, suited for systems expecting PNP inputs. Choose based on your controller's input type.\u003c\/p\u003e\n\u003ch4\u003eQ: What materials can the LJ12A3-4-Z\/BY inductive proximity switch detect?\u003c\/h4\u003e\n\u003cp\u003eA: As an inductive proximity sensor, this switch detects \u003cstrong\u003emetallic objects only\u003c\/strong\u003e — including steel, iron, aluminum, copper, and other conductive metals. It does not detect plastic, wood, glass, or other non-metallic materials. The maximum sensing distance for ferrous metals is 4mm.\u003c\/p\u003e\n\u003ch4\u003eQ: Is this proximity switch compatible with 3D printers and CNC machines?\u003c\/h4\u003e\n\u003cp\u003eA: Yes! The LJ12A3-4-Z\/BY is a popular choice for 3D printer bed leveling endstops and CNC machine homing\/limit sensing. Its standard M12 threaded cylindrical body fits most commonly available mounting brackets, and both NPN and PNP variants are widely supported by popular control boards.\u003c\/p\u003e\n\u003c!-- production-packaging-notice --\u003e\n\u003ch3\u003eProduction \u0026amp; Packaging Notice\u003c\/h3\u003e\n\u003cp\u003eTo 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.\u003c\/p\u003e\n\u003cscript type=\"application\/ld+json\"\u003e{\"@context\": \"https:\/\/schema.org\", \"@type\": \"FAQPage\", \"mainEntity\": [{\"@type\": \"Question\", \"name\": \"What is the difference between the NPN and PNP versions of the LJ12A3-4-Z proximity switch?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"The NPN version (LJ12A3-4-Z\/BX) outputs a sinking signal — the output wire pulls LOW (to ground) when an object is detected, commonly used with PLCs and microcontrollers that accept NPN inputs. The PNP version (LJ12A3-4-Z\/BY) outputs a sourcing signal — the output wire pulls HIGH (to supply voltage) when activated, suited for systems expecting PNP inputs. 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