10Pcs KW12-3 Micro Roller Lever Limit Switch PCB Microswitch

10Pcs KW12-3 Micro Roller Lever Arm Limit Switch – PCB Microswitch

Get reliable, snap-action switching in a compact package. This pack of 10 KW12-3 micro roller lever limit switches delivers fast, precise open/close triggering for a wide range of electronics, automation, and DIY projects. Built with PCB-mount terminals, these microswitches are easy to integrate into circuit boards and deliver consistent performance across thousands of cycles.

Made in Mainland China.

Key Features

• Roller Lever Actuator: Smooth, consistent actuation via the roller lever arm for accurate positional triggering
• Snap-Action Mechanism: Instantaneous contact make/break action ensures fast, clean switching with minimal bounce
• PCB Terminal Design: Solder-ready PCB terminals for straightforward circuit board integration
• Wide Operating Temperature: Rated for -40°C to 70°C — suitable for demanding environments
• AC Rated: Handles AC 125V–250V at up to 5A current for versatile use
• Compact Form Factor: Measures just 20 × 10 × 6 mm (L × W × H) — fits tight enclosures with ease
• Value Pack: Comes with 10 switches so you always have spares on hand

Technical Specifications

How It Works

The KW12-3 uses a spring-loaded reed mechanism. When an external mechanical force (via roller, lever, or pin) acts on the actuator and reaches its critical travel point, the reed snaps instantaneously — making or breaking the circuit contact in a fraction of a second. When the force is removed, the spring reverses the action, resetting the switch. This snap-action design provides short stroke actuation, small contact spacing, and fast switching performance.

Common Applications

• Computer mice and pointing devices
• Automotive and vehicle electronics
• Communications and test equipment
• Small home appliances (microwave ovens, rice cookers)
• Gas water heaters and gas burners
• Floating ball and fluid-level equipment
• Medical and laboratory instruments
• Building automation and control systems
• Electric power tools
• 3D printers and CNC machines (end-stop switches)

What's in the Box

• 10 × KW12-3 Micro Roller Lever Limit Switches

Learn more: OSHA guidance on hand and power tools

Frequently Asked Questions

Q: What is the KW12-3 micro roller lever limit switch used for?

A: The KW12-3 PCB microswitch is widely used as a position/limit sensor in electronics, automation systems, home appliances, 3D printers, CNC machines, and more. Its roller lever arm detects mechanical movement and triggers an instantaneous open or close circuit action.

Q: Are these switches compatible with 3D printer end-stops?

A: Yes. The KW12-3 roller lever microswitch is one of the most popular choices for 3D printer end-stop and homing switches. Its compact size and PCB-mount terminals make it straightforward to install on most printer control boards.

Q: What voltage and current do these microswitches support?

A: Each KW12-3 switch is rated for AC 125V–250V at up to 5A. This makes them suitable for a broad range of low-to-medium power electronic and automation applications.

Q: How do I mount the KW12-3 microswitch?

A: The KW12-3 features PCB (printed circuit board) terminals, meaning you can solder them directly onto a circuit board. The compact 20 × 10 × 6 mm body also allows panel or bracket mounting using the pre-drilled holes on the switch body.

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.