The **SMT-0827-S-9-R** is a surface-mount (SMT) piezoelectric transducer (buzzer) manufactured by **PUI Audio**. It is designed for compact electronic devices requiring audible alerts or feedback. --- ### 1. Key Technical Specifications The following table summarizes the primary electrical and physical characteristics of the component: | Feature | Specification | | :--- | :--- | | **Technology** | Piezoelectric | | **Rated Voltage** | 9 Vp-p | | **Operating Voltage Range** | 1 ~ 25 Vp-p | | **Frequency (Resonant)** | 2,700 Hz ± 500 Hz | | **Sound Pressure Level (SPL)** | ≥ 75 dB @ 10cm | | **Current Consumption** | ≤ 3 mA | | **Capacitance** | 11,000 pF ± 30% | | **Mounting Type** | Surface Mount (SMD) | | **Operating Temperature** | -20°C to +70°C | --- ### 2. Physical Dimensions & Construction * **Form Factor:** It features a square or rectangular footprint optimized for pick-and-place assembly machines. * **Size:** Approximately 8mm x 8mm x 2.5mm. * **Housing Material:** LCP (Liquid Crystal Polymer), which is heat-resistant for lead-free reflow soldering processes. * **Drive Type:** **External Drive**. This means the component does not have an internal oscillation circuit; it requires an external AC signal (square wave) at the resonant frequency to produce sound. --- ### 3. Application Circuit Example Because this is a piezo element, it acts like a capacitor. To drive it effectively from a microcontroller (MCU), a simple transistor circuit is often used to provide the necessary voltage swing. ```cpp // Example: Driving a piezo with an Arduino/MCU void setup() { pinMode(9, OUTPUT); // Connect Pin 9 to a transistor driving the SMT-0827 } void loop() { tone(9, 2700); // Send a 2.7kHz square wave delay(500); // Sound for 500ms noTone(9); // Silence delay(1000); } ``` --- ### 4. Advantages and Use Cases * **Low Power:** Uses very little current compared to magnetic buzzers, making it ideal for battery-operated devices. * **Slim Profile:** The low-profile design (2.5mm height) fits into handheld electronics like medical monitors, glucose meters, and IoT sensors. * **Durability:** No moving mechanical parts (like a striker), leading to a longer lifespan.