The **M2MS-B-R** is a specific model of a **Miniature Micro Switch** produced by **CIT Relay & Switch**. These components are widely used in industrial, automotive, and consumer electronics due to their compact size and high reliability. Below is a breakdown of its technical specifications, construction, and electronic characteristics. --- ## 1. Technical Specifications The "M2MS" series is defined by its sub-miniature footprint and specific electrical ratings. | Feature | Specification | | :--- | :--- | | **Circuitry** | SPDT (Single Pole Double Throw) | | **Switch Function** | ON - (ON) / Momentary | | **Contact Rating** | 5A @ 125VAC / 3A @ 250VAC / 3A @ 30VDC | | **Electrical Life** | 50,000 Cycles (Average) | | **Contact Resistance** | < 50 mΩ initial | | **Insulation Resistance** | > 100 MΩ min @ 500VDC | | **Dielectric Strength** | 1000Vrms minimum | | **Operating Temperature** | -25°C to +85°C | --- ## 2. Part Number Breakdown (M2MS-B-R) The nomenclature explains the specific physical and electronic configuration of this unit: * **M2MS**: Series designation for the Sub-Miniature Micro Switch. * **B**: Refers to the **Actuator Type**. In this series, "B" typically represents a **Short Roller Lever**. * **R**: Refers to the **Terminal Type**. "R" usually indicates **Right Angle PC Pin** terminals (designed for horizontal PCB mounting). --- ## 3. Internal Electronic Construction A micro switch works on a "snap-action" mechanism. Here is how the M2MS-B-R is built internally: ### Actuation Mechanism The **Roller Lever (B)** reduces friction when the switch is triggered by a moving cam or mechanical arm. This mechanical energy is transferred to a spring-loaded contact inside the housing. ### Contact Material Most M2MS models use **Silver-plated copper alloy** contacts. * **Silver** provides excellent conductivity. * The plating prevents oxidation, ensuring low contact resistance over thousands of cycles. ### Housing The outer shell is made of **PBT (Polybutylene Terephthalate)** or similar UL94V-0 rated plastics, which are flame retardant and provide high electrical insulation between the terminals. --- ## 4. Typical Applications Because of the **Right Angle (R)** terminal configuration and **Roller Lever (B)**, this part is commonly found in: 1. **Limit Switching:** Detecting the end of travel for a printer carriage or CNC axis. 2. **Safety Interlocks:** Ensuring a door or panel is closed before a machine operates. 3. **PCB Control Boards:** Where space is limited and the switch must be mounted flat against the board. ---