The **LSMT2-34040-R** is a high-performance, surface-mount (SMT) magnetic buzzer/transducer designed for applications requiring a compact footprint and reliable sound output. --- ### 1. Key Technical Specifications | Parameter | Specification | | :--- | :--- | | **Type** | Magnetic Transducer (External Drive) | | **Rated Voltage** | 3.6 Vp-p | | **Operating Voltage** | 2.5 ~ 4.5 Vp-p | | **Rated Current** | Max. 100 mA | | **Sound Pressure Level (SPL)** | Min. 87 dB at 10cm | | **Resonant Frequency** | 2,700 Hz | | **Coil Resistance** | 15 ± 3 Ω | | **Operating Temperature** | -40°C to +85°C | --- ### 2. Functional Description The LSMT2-34040-R is a **magnetic transducer**, which differs from an "indicator" in that it does not have internal circuitry to generate the tone. * **External Drive Required:** To produce sound, an external square wave signal (typically at the resonant frequency of 2.7 kHz) must be applied to the pins. * **Operating Principle:** It utilizes an electromagnetic coil to move a metal diaphragm. When an oscillating current passes through the coil, the resulting magnetic field fluctuates, causing the diaphragm to vibrate and create sound waves. --- ### 3. Physical & Mechanical Attributes * **Mounting Type:** Surface Mount (SMD/SMT), suitable for automated "pick and place" assembly. * **Dimensions:** Typically 4.0mm x 4.0mm x 2.0mm (Ultra-miniature). * **Housing Material:** High-temperature plastic (LCP or similar) capable of withstanding lead-free reflow soldering temperatures. --- ### 4. Typical Application Circuit Since this is a magnetic device, it requires a transistor or a MOSFET to drive it, as a standard Microcontroller (MCU) I/O pin cannot provide the 100mA required. ```cpp // Example: Driving with an MCU via PWM // Frequency: 2700 Hz // Duty Cycle: 50% void setup() { pinMode(BUZZER_PIN, OUTPUT); } void loop() { tone(BUZZER_PIN, 2700); // Generates square wave at resonant freq delay(500); noTone(BUZZER_PIN); delay(500); } ``` --- ### 5. Common Use Cases * **Portable Electronics:** Smartphones, tablets, and smartwatches. * **Medical Devices:** Glucose monitors and portable diagnostic tools. * **Industrial:** Status alerts for handheld scanners or compact controllers. * **Security:** Keypad entry confirmation sounds. ---