The **LSMT2-11540-R** is an electronic component primarily categorized as a **Surface Mount (SMT) Magnetic Transducer** or Buzzer. It is designed to provide acoustic feedback (beeps or tones) in compact electronic devices. --- ## 1. Component Specifications Below are the typical technical characteristics of the LSMT2-11540-R: | Parameter | Specification | | :--- | :--- | | **Type** | Magnetic Transducer (External Drive) | | **Mounting Type** | Surface Mount (SMT) | | **Operating Voltage** | 3.0V to 5.0V (Typical) | | **Rated Voltage** | 3.6 Vp-p | | **Current Consumption** | ~90mA (at rated voltage) | | **Sound Pressure Level (SPL)** | ≥ 85 dB at 10cm | | **Resonant Frequency** | 2700 Hz - 2800 Hz | | **Coil Resistance** | 15.0 ± 3.0 Ω | | **Operating Temperature** | -40°C to +85°C | --- ## 2. Key Electronic Features ### A. Magnetic Transducer Mechanism Unlike a "piezo" buzzer which uses ceramic crystals, this is a **magnetic** device. It consists of: * **A permanent magnet:** To create a baseline magnetic field. * **A coil:** When current passes through, it creates an electromagnetic field. * **A metal diaphragm:** The interaction between the magnetic fields causes the diaphragm to vibrate and create sound. ### B. External Drive Requirement The "Transducer" designation means it **does not** have an internal oscillating circuit. To produce sound, the engineer must provide an external square wave signal at the resonant frequency (typically 2730 Hz). ### C. Reflow Solder Compatibility The "R" suffix and "SMT" designation indicate that the part is designed to withstand the high temperatures of automated reflow soldering ovens, making it ideal for mass-production PCB assembly. --- ## 3. Recommended Application Circuit To drive this component using a microcontroller (like an Arduino or ESP32), a simple transistor switching circuit is required because the current draw (~90mA) is higher than what a standard GPIO pin can provide. ```cpp // Example: Generating a tone for a 2700Hz Resonant Frequency int buzzerPin = 9; // Connected to the base of a NPN transistor void setup() { pinMode(buzzerPin, OUTPUT); } void loop() { tone(buzzerPin, 2700); // Send 2.7kHz square wave delay(500); noTone(buzzerPin); delay(500); } ``` --- ## 4. Common Applications * **Consumer Electronics:** Microwave ovens, washing machines, and timers. * **Medical Devices:** Alarms for heart rate monitors or fluid pumps. * **Handheld Devices:** POS terminals and scanners for "beep" confirmation. * **Automotive:** Dashboard alerts and proximity sensors.