The **ALSP-142-R** is a specific electronic component primarily categorized as an **Electromagnetic Sounder** or **Magnetic Buzzer**. It is designed to convert electrical signals into audible sound through electromagnetic induction. --- ## 1. Technical Specifications Below are the typical technical parameters for this type of surface-mount (SMD) magnetic sounder: | Parameter | Typical Value | | :--- | :--- | | **Rated Voltage** | 1.5V - 3.6V DC | | **Operating Voltage Range** | 1.0V ~ 5.0V | | **Rated Current** | Max 80 - 100 mA | | **Resonant Frequency** | 2,730 Hz (Standard) | | **Sound Pressure Level (SPL)** | Min 80 dB at 10cm | | **Coil Resistance** | 12 ± 3 Ω | | **Operating Temperature** | -30°C to +70°C | --- ## 2. Structural Composition The ALSP-142-R consists of several internal electronic and mechanical parts: 1. **Housing (Case):** Usually made of LCP (Liquid Crystal Polymer) to withstand high-temperature reflow soldering. 2. **Vibration Diaphragm:** A thin metal plate that moves back and forth to create sound waves. 3. **Magnet:** Provides a permanent magnetic field. 4. **Electromagnetic Coil:** When current passes through this coil, it creates a fluctuating magnetic field that interacts with the permanent magnet. 5. **Terminals/Pads:** The "R" in the suffix often denotes the packaging style (Tape & Reel) for automated SMD assembly. --- ## 3. Operating Principle Unlike a "piezo" buzzer which uses the deformation of ceramic, the ALSP-142-R is **Magnetic**: * **Step 1:** An oscillating electrical signal (Square Wave) is applied to the coil. * **Step 2:** The coil generates a varying magnetic field. * **Step 3:** This field pulls and releases the metal diaphragm at the frequency of the input signal. * **Step 4:** The rapid movement of the diaphragm displaces air, creating sound. --- ## 4. Key Implementation Notes * **Driving Circuit:** Since this is a transducer (not a self-driven buzzer), it requires an external oscillating circuit (like a PWM signal from a microcontroller) to function. * **Polarity:** These components are polarized. Ensure the positive (+) terminal matches the PCB layout. * **Soldering:** Being an SMD part, it is designed for IR reflow soldering. However, care must be taken not to wash the component after soldering, as liquid can enter the sound hole and damage the diaphragm.