The **LSMT2-115G0-R** is a high-performance, surface-mount (SMD) magnetic transducer, commonly referred to as a **magnetic buzzer**. It is designed for compact electronic devices that require reliable acoustic signaling. --- ### 1. General Specifications Below are the primary technical parameters for the LSMT2-115G0-R: | Parameter | Value | | :--- | :--- | | **Type** | Magnetic Transducer (External Drive) | | **Rated Voltage** | 1.5V (Operating range typically 1.0 - 2.0V) | | **Rated Current** | Max 80mA | | **Sound Pressure Level (SPL)** | Min 85dB at 10cm | | **Resonant Frequency** | 2,730 Hz | | **Coil Resistance** | 5.5 ± 1.0 $\Omega$ | | **Operating Temp** | -40°C to +85°C | --- ### 2. Physical Characteristics The "LSMT" series is characterized by its small footprint, optimized for automated pick-and-place assembly. * **Package Dimensions:** 11.5mm x 11.5mm x 3.0mm. * **Mounting Type:** Surface Mount Device (SMD). * **Weight:** Approximately 0.5g. * **Housing Material:** High-temperature plastic (LCP) capable of withstanding reflow soldering temperatures. --- ### 3. Functional Working Principle Unlike an "Indicator" (which has internal circuitry to generate a beep), the LSMT2-115G0-R is a **Transducer**. * **External Drive Required:** It requires an external oscillating signal (usually a square wave) to function. * **Mechanism:** When a square wave is applied to the coil, it generates a varying magnetic field. This field interacts with a permanent magnet and a metal diaphragm, causing the diaphragm to vibrate and create sound waves. --- ### 4. Typical Application Circuit To drive this component using a Microcontroller (MCU), a transistor is required because the current draw (80mA) exceeds standard GPIO limits. ```cpp // Example: Driving the buzzer using Arduino PWM void setup() { pinMode(9, OUTPUT); // Connect Pin 9 to Transistor Base } void loop() { tone(9, 2730); // Generate the resonant frequency delay(500); // Beep for 0.5 seconds noTone(9); // Stop delay(500); } ``` --- ### 5. Key Design Considerations 1. **Flyback Diode:** It is recommended to place a diode (e.g., 1N4148) in parallel with the buzzer to protect the driving transistor from inductive voltage spikes. 2. **Frequency Matching:** For maximum volume, the input signal must be as close to **2,730 Hz** as possible. Sound output drops significantly if the frequency deviates from this resonant point. 3. **Polarity:** Ensure the "+" mark on the casing matches the positive side of your circuit.