The **APS2714S-R** is a high-performance, surface-mount (SMT) piezoelectric audio indicator (buzzer) manufactured by **PUI Audio**. It is designed for compact electronic applications that require clear audible feedback. --- ### 1. Key Technical Specifications The following table outlines the core electronic and physical characteristics of the APS2714S-R: | Parameter | Specification | | :--- | :--- | | **Technology** | Piezoelectric | | **Rated Voltage** | 12 Vp-p | | **Voltage Range** | 1 ~ 25 Vp-p | | **Current Consumption** | Max 3 mA (at 12 Vp-p) | | **Sound Pressure Level (SPL)** | 80 dB @ 10cm / 12 Vp-p | | **Resonant Frequency** | 4,000 Hz ± 500 Hz | | **Operating Temperature** | -30°C to +85°C | | **Mounting Type** | Surface Mount (SMT) | --- ### 2. Functional Details #### Internal Construction Unlike "indicators" that have a built-in drive circuit (and beep as soon as DC voltage is applied), the APS2714S-R is an **External Drive Transducer**. This means: * It requires an external AC signal or square wave to produce sound. * The tone/pitch can be varied by changing the input frequency. * It is more energy-efficient than electromagnetic buzzers. #### Piezoelectric Element The part consists of a ceramic disc bonded to a metal plate. When a voltage is applied, the ceramic expands and contracts (the inverse piezoelectric effect), causing the diaphragm to vibrate and move air, creating sound waves. --- ### 3. Typical Driving Circuit To operate this part with a microcontroller (like an Arduino or STM32), a simple transistor switching circuit is often used to handle the voltage requirements. ```cpp // Example: Driving the APS2714S-R using PWM void setup() { pinMode(9, OUTPUT); // Connect to Transistor Base } void loop() { tone(9, 4000); // Send 4kHz square wave (Resonant Frequency) delay(500); noTone(9); delay(500); } ``` --- ### 4. Applications * **Medical Devices:** Handheld monitors and diagnostic tools. * **Consumer Electronics:** Microwave beepers, digital clocks, and calculators. * **Industrial:** Alarm systems and control panel feedback. * **Mobile Devices:** Due to its low profile and SMT design.