The **CD08CM0CB-R** is a high-performance, ultra-compact **Rotary Coded Switch** manufactured by **C&K Components** (now part of Littelfuse). These switches are primarily used to set binary values manually on a circuit board, such as addressing or mode selection. --- ## 1. Technical Specifications The following table highlights the core electronic and mechanical characteristics of the CD08CM0CB-R: | Parameter | Specification | | :--- | :--- | | **Switch Type** | Rotary Coded Switch | | **Output Code** | BCD (Binary Coded Decimal) | | **Number of Positions** | 8 (0 through 7) | | **Actuator Type** | Flush, Screwdriver Slot | | **Mounting Type** | Surface Mount (SMT), Gull Wing | | **Contact Rating** | 0.4 VA @ 20V AC/DC (Logic Level) | | **Operating Temperature** | -25°C to 85°C | | **Process Sealed** | Yes (Washable) | --- ## 2. Key Electronic Features ### A. BCD Coding (Binary Coded Decimal) The "08" in the part number indicates 8 positions. As you rotate the actuator, the internal contacts bridge specific output pins to a common pin. This creates a 3-bit binary output representing values 0–7. ### B. Contact Reliability The contacts are typically **gold-plated**. This is crucial for "logic level" applications where voltages and currents are very low, as gold prevents oxidation that would otherwise cause signal failure. ### C. Process Compatibility * **Surface Mount (SMT):** Designed for automated "pick and place" assembly. * **Submersible/Washable:** The part is sealed with an O-ring. This allows the PCB to be put through automated aqueous or chemical cleaning processes after soldering without damaging the switch internals. --- ## 3. Pin Configuration and Internal Logic While exact pin maps depend on the footprint, a standard 8-position BCD switch utilizes a **Common (C)** pin and three output pins representing binary weights ($2^0, 2^1, 2^2$). | Position | Binary Output (Hex/Dec) | Pin 1 ($2^0$) | Pin 2 ($2^1$) | Pin 4 ($2^2$) | | :--- | :--- | :--- | :--- | :--- | | 0 | 000 | Open | Open | Open | | 1 | 001 | **Closed** | Open | Open | | 3 | 011 | **Closed** | **Closed** | Open | | 7 | 111 | **Closed** | **Closed** | **Closed** | --- ## 4. Common Applications * **Industrial Controls:** Setting Modbus or CANbus node addresses. * **Networking:** Configuring hardware IDs for peripheral devices. * **Instrumentation:** Selecting pre-set calibration modes or operational frequencies. * **Consumer Electronics:** Hard-coding region settings on a mainboard.