## KPE-14-R: Piezoelectric Audio Indicator The **KPE-14-R** is a high-performance piezoelectric audio indicator (buzzer) commonly used in consumer electronics, medical devices, and industrial control panels. It is categorized as a "transducer" or "buzzer" that converts electrical signals into audible sound. ### Technical Specifications | Parameter | Specification | | :--- | :--- | | **Rated Voltage** | 12V DC | | **Operating Voltage Range** | 3.0V to 20V DC | | **Current Consumption** | Max 10mA (at rated voltage) | | **Sound Pressure Level (SPL)** | Min 80dB (at 30cm / 12V DC) | | **Resonant Frequency** | 3,300 ± 500 Hz | | **Operating Temperature** | -20°C to +70°C | | **Mounting Type** | Through-hole (PCB) | --- ### Key Electronic Components & Construction 1. **Piezoelectric Element**: The core is a ceramic disc (Lead Zirconate Titanate) bonded to a metal plate (usually brass or stainless steel). When voltage is applied, the ceramic deforms, vibrating the plate to create sound waves. 2. **Internal Drive Circuit**: Unlike a basic transducer, the "R" in the series often signifies a built-in frequency generator. This means it only requires a stable DC voltage to produce a continuous tone, rather than an external PWM signal. 3. **Housing**: Typically constructed from PBT (Polybutylene Terephthalate) or ABS plastic, designed to act as a resonant chamber to amplify the sound pressure. ### Physical Characteristics * **Pin Configuration**: Usually features two pins (Positive and Negative) with a specific pitch (e.g., 7.5mm or 10mm depending on the specific revision). * **Dimensions**: Compact cylindrical design, typically around 14mm in diameter. * **Color**: Standard models are usually black. --- ### Implementation Considerations * **Polarity**: This is a polarized component. The positive terminal (usually marked with a '+' or a longer lead) must be connected to the positive supply. * **Driving Circuitry**: Since it consumes low current (10mA), it can often be driven directly by a microcontroller GPIO pin, though using a transistor (like a 2N2222) is recommended to protect the MCU from back-EMF or current spikes. * **Sound Output**: To achieve the maximum 80dB output, ensure the mounting environment does not obstruct the sound hole on the top of the casing.