The **KEPF-12PC-R** is a specific electronic component categorized as a **Piezoelectric Transducer (Buzzer)**. It is primarily used to generate sound in electronic devices via the piezoelectric effect. --- ### 1. General Specifications The KEPF-12PC-R is designed for high-efficiency sound output with low power consumption. | Parameter | Specification | | :--- | :--- | | **Type** | Piezoelectric Transducer (External Drive) | | **Rated Voltage** | 3 - 25 Vp-p (Square Wave) | | **Sound Pressure Level (SPL)** | Min 75 dB @ 10cm / 3Vp-p / 4kHz | | **Resonant Frequency** | 4,000 Hz ± 500 Hz | | **Capacitance** | ~12,000 pF @ 120Hz | | **Operating Temperature** | -20°C to +70°C | | **Mounting Type** | Through-hole (PCB Mount) | --- ### 2. Physical Construction The part is engineered for durability and compact PCB integration. * **Housing Material:** Usually Black PBT (Polybutylene Terephthalate) or similar high-temp plastic. * **Dimensions:** Typically 12mm in diameter and 7mm to 9mm in height. * **Terminals:** Two PC pins for direct soldering to a printed circuit board. * **Design:** A "Washable" or "Sealed" design is often denoted by the "R" suffix or a top sticker, allowing the board to be cleaned after soldering without damaging the internal ceramic element. --- ### 3. Operating Principle Unlike an *indicator* (which has internal circuitry to beep when DC power is applied), the KEPF-12PC-R is a **transducer**. * **Drive Circuitry Required:** It requires an external oscillating signal (square wave) to function. * **The Piezo Effect:** When an AC voltage is applied to the ceramic disc inside, it vibrates mechanically, moving the surrounding air to create sound waves. * **Frequency Tuning:** To achieve the maximum volume (SPL), the input frequency must match the resonant frequency (4.0 kHz). --- ### 4. Typical Application Circuit To drive this component using a microcontroller (like an Arduino or STM32), a simple transistor switching circuit is often used to handle the voltage peaks. ```cpp // Example: Driving a 4kHz tone on an Arduino void setup() { pinMode(9, OUTPUT); // Pin connected to Transistor Base } void loop() { tone(9, 4000); // Send 4000Hz square wave delay(1000); noTone(9); delay(1000); } ``` ---