The **EM14A0B-R25-R032S** is a high-quality rotary optical encoder manufactured by **Bourns**. It is part of the EM14 series, designed for applications requiring high reliability, a long cycle life, and a compact form factor. --- ## 1. Technical Specifications | Parameter | Specification | | :--- | :--- | | **Part Series** | EM14 (14 mm Rotary Optical Encoder) | | **Resolution** | 32 Pulses per Revolution (PPR) | | **Output Type** | 2-bit Quadrature (Channel A and B) | | **Input Voltage** | 5.0 VDC ±5% | | **Supply Current** | 26 mA maximum | | **Rotational Life** | Up to 1,000,000 cycles | | **Operating Temp** | -40°C to +70°C | | **Switch Type** | Integrated Push Momentary Switch | --- ## 2. Part Number Breakdown Understanding the specific suffix codes helps identify the physical and electrical characteristics: * **EM14**: Series name (14 mm Optical Encoder). * **A**: Terminal configuration (PC Pin, side exit). * **0**: No bushing (or standard non-threaded, depending on specific datasheet revision). * **B**: Shaft style (typically a flatted shaft). * **R25**: Shaft length (e.g., 25mm). * **R**: Resolution code. * **032**: 32 pulses per 360-degree rotation. * **S**: Includes an internal momentary push switch. --- ## 3. Key Electronic Components & Features ### A. Optical Technology Unlike mechanical encoders that use physical brushes (which wear out), the EM14 uses an **internal LED and photodiode array**. A slotted disk interrupts the light beam, creating clean electrical pulses. * **Benefit:** Zero contact noise (bouncing) and significantly longer lifespan. ### B. Quadrature Output The device outputs two square waves (Channel A and B) offset by 90 degrees. * **Clockwise:** A leads B. * **Counter-Clockwise:** B leads A. * This allows the microcontroller to determine both the **speed** and **direction** of rotation. ### C. Integrated Push Switch The "S" at the end of the part number indicates a momentary tactile switch. This allows the encoder to act as a "Select" or "Enter" button when the shaft is pressed axially. --- ## 4. Typical Wiring Diagram The device usually features 5 or 6 pins. Below is the standard pinout logic: ```text Pin 1: Ground (GND) Pin 2: Push Switch Output Pin 3: Channel A (Output) Pin 4: VCC (+5V Power) Pin 5: Channel B (Output) Pin 6: Ground (Common for Switch) ``` --- ## 5. Applications * **Medical Equipment:** Precision adjustment for patient monitors. * **Professional Audio:** Volume and parameter control in mixing consoles. * **Industrial Controls:** Menu navigation for HMI (Human Machine Interface) panels. * **Test & Measurement:** Oscilloscopes and signal generators.