The **MH21TAD-R** is a specific electronic component typically identified as a **tactile switch** (or tact switch) manufactured by companies like **Mitsumi**. These components are fundamental in human-interface devices, providing physical feedback when pressed. --- ## 1. Component Overview The MH21TAD-R belongs to the category of electromechanical switches. It is designed for low-current applications where a momentary "make" connection is required. | Feature | Description | | :--- | :--- | | **Type** | Momentary Tactile Switch | | **Mounting Style** | Surface Mount Technology (SMT / SMD) | | **Actuation Type** | Top Actuated | | **Contact Arrangement** | SPST (Single Pole Single Throw) - Normally Open | --- ## 2. Key Technical Specifications While specific datasheets can vary by manufacturer revisions, the "TAD-R" series generally follows these parameters: ### Electrical Characteristics * **Contact Rating:** Usually 12V DC, 50mA. * **Insulation Resistance:** 100MΩ minimum. * **Contact Resistance:** 100mΩ maximum (initial). * **Dielectric Strength:** 250V AC for 1 minute. ### Mechanical Characteristics * **Operating Force:** Typically ranges between **1.6N to 2.5N** (approx. 160gf to 250gf). * **Travel Distance:** Short stroke, usually around **0.25mm**. * **Durability:** Rated for approximately 100,000 to 500,000 cycles depending on the specific sub-model. --- ## 3. Physical Construction The part number suffix often dictates the packaging and physical dimensions: 1. **Housing:** Heat-resistant plastic (LCP or Nylon) to withstand SMT reflow soldering. 2. **Actuator (Stem):** The button part that the user presses. 3. **Contact Dome:** A stainless steel or copper alloy disc that provides the "click" feel and completes the circuit. 4. **Terminals:** Usually J-lead or Gull-wing shaped leads for PCB soldering. --- ## 4. Common Applications Due to its small footprint and reliability, the MH21TAD-R is commonly found in: * **Consumer Electronics:** Volume buttons on tablets, power buttons on cameras. * **Automotive:** Dashboard controls, key fobs. * **Industrial:** Interface panels for PLC controllers. * **Computing:** Peripheral reset buttons or mouse buttons. --- ## 5. Circuit Representation In a schematic, this part is represented as a simple open switch that closes only while pressure is applied. ```text (Term 1) ----/ ---- (Term 2) Switch ```