The **LPA-41PA-R** is a high-performance, ultra-compact piezoelectric sounder (buzzer) manufactured by **Mallory Sonalert Products**. It is primarily used for providing audible feedback in small electronic devices. --- ### 1. Key Technical Specifications The following table outlines the primary electrical and physical characteristics of the LPA-41PA-R: | Parameter | Specification | | :--- | :--- | | **Transducer Type** | Piezoelectric (External Drive) | | **Rated Voltage** | 3.0 Vp-p | | **Operating Voltage Range** | 1.0 - 25 Vp-p | | **Current Consumption** | Max 1.0 mA (at 3Vp-p, 4.0kHz) | | **Sound Pressure Level (SPL)** | Min 75 dB @ 10cm | | **Resonant Frequency** | 4,000 Hz ± 500 Hz | | **Mounting Type** | Surface Mount (SMT) | | **Dimensions** | 4.0 x 4.0 x 1.9 mm | --- ### 2. Electronic Composition and Working Principle The LPA-41PA-R is an **external drive** piezo element, meaning it does not have internal circuitry to generate an oscillation. * **Piezoelectric Ceramic:** The core component is a ceramic disc that expands and contracts when an alternating voltage is applied. * **Capacitive Load:** Electronically, the device behaves like a capacitor. Because of this, it consumes very little power compared to electromagnetic buzzers. * **Housing:** It is encased in a Liquid Crystal Polymer (LCP) or similar high-temperature plastic to withstand reflow soldering processes. ### 3. Application Circuit Requirements To operate this part, your electronic design must include: 1. **Frequency Generator:** A microcontroller (MCU) PWM pin or a 555 timer circuit set to ~4.0 kHz. 2. **Driving Signal:** A square wave or sine wave. Peak-to-peak voltage determines the loudness. 3. **Circuit Protection:** Often a parallel resistor is used to discharge the piezo capacitance, or a transistor switching circuit is used to provide the necessary Vp-p. ### 4. Comparison: Piezo vs. Magnetic | Feature | LPA-41PA-R (Piezo) | Magnetic Transducer | | :--- | :--- | :--- | | **Power Consumption** | Very Low (< 1mA) | High (20-80mA) | | **Voltage Range** | Wide (Up to 25V) | Narrow (1.5 - 12V) | | **Size** | Ultra-thin/Small | Bulky | | **Sound Quality** | High Pitch/Tonal | Lower Frequency/Rich | ---