The **CD08CM0AB-R** is a specific type of **Rotary Coded Switch** (typically a DIP rotary switch) manufactured by C&K (now part of Littelfuse). These components are used to set configurations on a circuit board manually, similar to a DIP switch but using a rotating dial. --- ### 1. General Specifications Below are the primary electrical and physical characteristics of the CD08CM0AB-R: | Feature | Specification | | :--- | :--- | | **Switch Type** | Rotary Coded Switch | | **Number of Positions** | 8 | | **Output Code** | Octal (0-7) | | **Actuator Style** | Flush, Screwdriver slot | | **Mounting Type** | Through-hole, Right Angle | | **Contact Rating** | 0.4 VA @ 20V AC/DC | | **Operating Temperature** | -25°C to 85°C | | **Process Sealed** | Yes (Washable) | --- ### 2. Pin Configuration and Truth Table The "08" in the part number indicates 8 positions. The device converts the mechanical position of the dial into a Binary Coded output. #### Terminal Layout * **Common (C):** The input terminal. * **1, 2, 4:** The output terminals representing binary bits ($2^0, 2^1, 2^2$). #### Truth Table (Octal) | Position | Pin 1 ($2^0$) | Pin 2 ($2^1$) | Pin 4 ($2^2$) | | :--- | :--- | :--- | :--- | | **0** | Open | Open | Open | | **1** | **Closed** | Open | Open | | **2** | Open | **Closed** | Open | | **3** | **Closed** | **Closed** | Open | | **4** | Open | Open | **Closed** | | **5** | **Closed** | Open | **Closed** | | **6** | Open | **Closed** | **Closed** | | **7** | **Closed** | **Closed** | **Closed** | --- ### 3. Key Electronic Features * **Logic Level Switching:** Designed for low-power signal switching (0.4 VA max). It is intended to interface directly with microcontrollers or logic gates, not for switching power loads. * **Right Angle Orientation:** The "AB" in the suffix usually denotes a right-angle mount, meaning the dial faces the side of the PCB rather than the top. * **Process Sealed:** The "R" at the end often signifies it is supplied in Tape & Reel packaging or features specific sealing (like an O-ring or epoxy) that allows the PCB to be water-washed after soldering without damaging the internals. * **Gold Contacts:** Typically uses gold-over-nickel plating to ensure high reliability and prevent oxidation in low-voltage logic circuits. --- ### 4. Common Applications * **Address Setting:** Setting the unique ID for a sensor or device on a bus (e.g., RS-485 or CAN bus). * **Mode Selection:** Choosing between different firmware operating modes. * **Industrial Controls:** Configuration of timers, limit settings, or calibration parameters.