10pcs KW12-3 Roller Lever Micro Limit Switch PCB Terminals NO/NC
10pcs KW12-3 Roller Lever Micro Limit Switch PCB Terminals NO/NC
KW12-3 Roller Lever Arm Micro Limit Switches — 10-Pack with PCB Terminals
Keep your electronics and automation projects running smoothly with this convenient 10-pack of KW12-3 Roller Lever Arm Micro Limit Switches. Featuring both Normally Open (NO) and Normally Close (NC) configurations, these compact PCB-mount switches deliver fast, reliable switching action in a wide range of applications — from DIY robotics and 3D printers to home appliances and industrial controls.
Key Features
- Dual Configuration: Supports Normal Open (NO) and Normal Close (NC) operation for versatile wiring options
- Roller Lever Arm: Smooth-rolling lever ensures consistent, repeatable mechanical actuation
- PCB Terminal Mounting: Direct circuit board solder terminals for a clean, secure installation
- Wide Temperature Range: Operates reliably from -40°C to 70°C (-40°F to 158°F)
- Rated Voltage: AC 125V – 250V
- Current Rating: 5A
- Compact Size: 20 × 10 × 6 mm (L × W × H) — fits tight spaces with ease
- Plastic Housing: Lightweight and durable construction
- Value Pack: 10 switches per order — great for prototyping, repairs, and bulk builds
How It Works
The KW12-3 micro limit switch uses an external mechanical force transmitted through its roller lever arm to act on an internal spring reed. When the force reaches a critical threshold, the reed snaps instantaneously — rapidly making or breaking the electrical circuit. When the force is removed, the spring reverses the action just as quickly. This snap-action mechanism delivers a small contact gap, short stroke, low actuation force, and ultra-fast switching response.
Specifications
| Model | KW12-3 |
| Switch Type | Micro Limit Switch (Roller Lever Arm) |
| Circuit | Normal Open / Normal Close (NO/NC) |
| Terminal Type | PCB Mount Solder Terminals |
| Rated Voltage | AC 125V – 250V |
| Current Rating | 5A |
| Operating Temperature | -40°C to 70°C |
| Body Material | Plastic |
| Dimensions | 20 × 10 × 6 mm |
| Quantity | 10 pieces |
| Country of Origin | Made in China |
Common Applications
- 3D printers (endstop / homing switches)
- CNC machines and robotics
- Computer mice and peripheral devices
- Automotive electronics
- Communications equipment
- Gas water heaters and gas burners
- Small home appliances, microwave ovens, and electric rice cookers
- Floating ball and level-sensing equipment
- Building automation and electric tools
- Test instruments and industrial controls
Package Contents
- 10 × KW12-3 Roller Lever Micro Limit Switches
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Frequently Asked Questions
Q: What is the difference between the Normal Open (NO) and Normal Close (NC) terminals on the KW12-3 micro limit switch?
A: The KW12-3 switch has three PCB terminals: Common (COM), Normally Open (NO), and Normally Close (NC). In its resting state, the COM and NC terminals are connected (circuit closed), while COM and NO are disconnected (circuit open). When the roller lever is actuated, the circuit switches — COM connects to NO and disconnects from NC. This lets you choose either configuration depending on your circuit design.
Q: Are these KW12-3 micro limit switches compatible with 3D printer endstops?
A: Yes! The KW12-3 roller lever micro limit switch is one of the most widely used endstop switches in 3D printers (such as those running RAMPS or similar boards). Their compact PCB terminal format, snap-action response, and consistent actuation make them an ideal drop-in replacement or upgrade for standard printer endstop positions.
Q: What voltage and current can the KW12-3 micro limit switch handle?
A: Each KW12-3 switch is rated for AC 125V to 250V at up to 5A. They are suitable for both low-voltage signal circuits (such as microcontroller inputs) and higher-voltage switching applications within the rated limits. Always ensure your application stays within the specified electrical ratings for safe, reliable operation.
Q: How are these switches mounted to a circuit board?
A: The KW12-3 features three through-hole PCB solder terminals (COM, NO, NC) on the bottom of the housing. Simply insert the terminals into matching holes on your PCB and solder them in place for a secure, permanent connection. No additional connectors or adapters are required for direct board mounting.
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.