The **M2RT-33-R** is a specific model of a **Rotary Encoder**, typically manufactured by companies like **Copals Electronics (Nidec)**. These components are used to convert the angular position or motion of a shaft into an analog or digital signal. --- ## 1. Technical Specifications The "M2RT" series generally refers to sub-miniature, manual-setting rotary switches or encoders. Below are the typical electronic characteristics for this part: | Parameter | Specification | | :--- | :--- | | **Type** | Manual Rotary Switch / Encoder | | **Number of Positions** | 10 Positions (Typically 0-9) | | **Output Code** | Real Binary Code / BCD (Binary Coded Decimal) | | **Mounting Type** | Through-hole (PC Pin) | | **Switching Rating** | 5V DC, 100mA | | **Contact Resistance** | 100 mΩ maximum | | **Operating Temperature** | -25°C to +70°C | --- ## 2. Pinout and Connection The device usually features a standardized pin layout to interface with microcontrollers or logic circuits. ### Pin Functions: 1. **Common (C):** The input pin that is connected to the ground or VCC depending on your logic (Pull-up or Pull-down). 2. **Bit 1 ($2^0$):** Represents the least significant bit. 3. **Bit 2 ($2^1$):** 4. **Bit 4 ($2^2$):** 5. **Bit 8 ($2^3$):** Represents the most significant bit. --- ## 3. How it Works (Logic Output) When the dial is turned to a specific number, the internal contacts close in a specific pattern to represent that number in Binary Coded Decimal (BCD). **Example Table for BCD Output:** | Position | Bit 8 ($2^3$) | Bit 4 ($2^2$) | Bit 2 ($2^1$) | Bit 1 ($2^0$) | | :--- | :---: | :---: | :---: | :---: | | **0** | Open | Open | Open | Open | | **1** | Open | Open | Open | **Closed** | | **2** | Open | Open | **Closed** | Open | | **5** | Open | **Closed** | Open | **Closed** | | **9** | **Closed** | Open | Open | **Closed** | --- ## 4. Common Applications * **Address Setting:** Used on industrial BUS systems (like RS-485 or CAN) to manually set a device's unique ID. * **Mode Selection:** Selecting operational modes on a PCB without needing a digital display. * **Parameter Adjustment:** Setting limit values or timers in embedded systems. ---