The **ST-10-R-B9** is a precision component typically associated with **Nidec Copal Electronics** (or similar manufacturers like Sumitomo). It is a surface-mount (SMD) high-precision rotary switch or trimmer, often used for circuit configuration and signal routing. --- ### 1. Key Technical Specifications Below are the primary electrical and mechanical characteristics for this specific model: | Parameter | Specification | | :--- | :--- | | **Component Type** | Rotary Coded Switch | | **Mounting Type** | Surface Mount (SMD / Gull-wing) | | **Logic/Coding** | Real Code (Binary Coded Decimal/Hex) | | **Number of Positions** | 10 Positions (0-9) | | **Actuator Style** | Rotor (Recessed/Flat) | | **Circuit Type** | SP10T (Single Pole 10 Throw) | | **Contact Rating** | 100mA @ 5V DC (Switching) | --- ### 2. Physical Design and Dimensions The "ST-10" series is known for its ultra-miniature footprint, designed for high-density PCB layouts. * **Size:** Usually 5.0mm x 5.0mm. * **Terminal Layout:** Features 3x3 or 4+1 terminal configurations depending on the specific sub-type. * **Rotor Design:** The "B" in the part number often indicates a specific actuator shape (like a cross-slot or flat-head) designed for manual or tool-assisted adjustment. * **Taping:** The "-R" suffix usually denotes **Tape and Reel** packaging, making it compatible with automated pick-and-place assembly machines. --- ### 3. Electrical Functionality The ST-10-R-B9 operates as a **Binary Coded Decimal (BCD)** selector. When you turn the dial: 1. It bridges a common terminal to a specific combination of output pins. 2. In a 10-position model, it outputs signals representing the digits 0 through 9. 3. **Gold-plated contacts** are standard to ensure low contact resistance and high reliability over the component's lifespan. --- ### 4. Typical Applications These parts are used in industrial and consumer electronics where "set-and-forget" configurations are needed: * **Address Setting:** Setting the ID for a node in a RS-485 or CAN bus network. * **Mode Selection:** Choosing operating modes on a PCB without needing a digital interface. * **Security Systems:** Manual code setting for hardware encryption or zone identification. ---