The **LS3718-S28-R** is a specific electronic component typically identified as a **Surface Mount (SMD) Magnetic Transducer** or Buzzer. It is widely used in consumer electronics for generating audible alerts and feedback signals. --- ### 1. Technical Specifications The following table highlights the primary electrical and physical characteristics of the LS3718-S28-R: | Parameter | Typical Value | Unit | | :--- | :--- | :--- | | **Type** | Magnetic Transducer (External Drive) | - | | **Operating Voltage** | 1.0 ~ 2.0 (Rated: 1.5) | Vp-p | | **Rated Current** | Max 80 | mA | | **Sound Pressure Level (SPL)** | Min 85 (at 10cm) | dB | | **Resonant Frequency** | 2730 | Hz | | **Coil Resistance** | 15 ± 3 | Ω | | **Operating Temperature** | -30 to +70 | °C | | **Mounting Type** | SMD (Surface Mount Device) | - | --- ### 2. Key Internal Components The "Electronic Parts" within this device consist of a magnetic circuit designed to convert electrical energy into mechanical vibration (sound): 1. **Voice Coil:** A fine copper wire coil that generates a magnetic field when an oscillating current passes through it. 2. **Permanent Magnet:** Provides a static magnetic field that interacts with the coil's field. 3. **Vibrating Diaphragm:** A thin metal plate (usually iron-based) that moves rapidly due to magnetic attraction/repulsion, pushing air to create sound waves. 4. **Housing/Base:** High-temperature plastic (LCP or PPS) designed to withstand the heat of reflow soldering. --- ### 3. Application & Driving Circuit Unlike an "indicator" (which has internal circuitry), a **transducer** like the LS3718-S28-R requires an external oscillating signal to function. * **Driving Signal:** It requires a square wave input at its resonant frequency (approx. 2730 Hz). * **Protection:** It is common practice to include a flyback diode in parallel with the transducer when driving it with a transistor to protect the circuit from voltage spikes. --- ### 4. Dimensions & Footprint * **Size:** The "3718" in the part number usually refers to the footprint dimensions (approx. 3.7mm x 1.8mm or similar proprietary sizing depending on the manufacturer). * **Reflow:** It is designed for standard SMT pick-and-place assembly lines.