The **LSMT2-105A1-R** is a high-performance **Surface Mount (SMT) Magnetic Transducer** (often referred to as a buzzer or sounder). These components are widely used in consumer electronics, medical devices, and industrial equipment to provide audible feedback or alarms. --- ## 1. Technical Specifications Below are the primary electrical and physical characteristics of the LSMT2-105A1-R: | Parameter | Specification | | :--- | :--- | | **Type** | Magnetic Transducer (External Drive) | | **Rated Voltage** | 1.5 Vo-p | | **Operating Voltage** | 1.0 ~ 2.0 Vo-p | | **Rated Current** | Max 100 mA | | **Sound Pressure Level (SPL)** | Min 85 dB (at 10cm) | | **Resonant Frequency** | 2,730 Hz | | **Coil Resistance** | 5.5 ± 1.0 $\Omega$ | | **Operating Temperature** | -40°C to +85°C | | **Mounting Type** | Surface Mount (SMT) | --- ## 2. Key Features * **External Drive Circuitry:** Unlike "indicators" which have internal oscillators, this is a **transducer**. It requires an external square wave signal at its resonant frequency (2730 Hz) to produce sound. * **Side-Opening Design:** The "105" series typically refers to a side-firing sound port, which allows the component to be placed in low-profile housings where the sound needs to exit through the side of the device. * **Reflow Solder Compatible:** Designed for automated assembly lines, it can withstand the high temperatures of lead-free reflow soldering processes. * **Compact Footprint:** Small dimensions make it ideal for handheld devices, pagers, and wearables. --- ## 3. Implementation (Drive Circuit) To operate this part, you generally use a transistor-driven circuit connected to a Microcontroller (MCU) PWM pin. ```cpp // Example: Driving the transducer using Arduino-style code int buzzerPin = 9; // PWM Pin void setup() { pinMode(buzzerPin, OUTPUT); } void loop() { // Generate a square wave at the resonant frequency (2730Hz) tone(buzzerPin, 2730); delay(500); noTone(buzzerPin); delay(500); } ``` ### Circuit Safety Note: Since this is an inductive load (a coil), it is highly recommended to place a **flyback diode** in parallel with the transducer to protect the driving transistor from voltage spikes when the signal is switched off. --- ## 4. Common Applications * **Medical Instrumentation:** Heart rate monitors or glucose meters. * **Consumer Electronics:** Washing machine "end of cycle" alerts, microwaves, or smart locks. * **Mobile Devices:** Feedback for button presses or low-battery warnings. * **Automotive:** Dash cluster alerts or proximity sensor beeps.