The **ROM-2235P-HD-R** is a high-performance piezoelectric transducer (buzzer) manufactured by PUI Audio. It is designed specifically for applications requiring high-density sound output in a compact, surface-mount form factor. --- ## 1. Technical Specifications The following table summarizes the primary electrical and physical characteristics: | Parameter | Specification | | :--- | :--- | | **Type** | Piezoelectric Indicator (External Drive) | | **Rated Voltage** | 3.0 Vp-p | | **Operating Voltage Range** | 1.0 ~ 25.0 Vp-p | | **Sound Pressure Level (SPL)** | 85 dB @ 10cm | | **Resonant Frequency** | 3,500 Hz ± 500 Hz | | **Capacitance** | 12,000 pF ± 30% @ 120Hz | | **Operating Temperature** | -40°C to +85°C | | **Mounting Type** | Surface Mount (SMD) | --- ## 2. Key Components & Construction The device consists of three main architectural elements: 1. **Piezoelectric Element:** A ceramic disc that expands and contracts when an alternating voltage is applied. This vibration creates sound waves. 2. **Housing:** Made of high-temperature LCP (Liquid Crystal Polymer), allowing the part to withstand lead-free reflow soldering processes. 3. **HD (High Density) Design:** The "HD" suffix indicates a design optimized for high output relative to its small footprint, making it ideal for portable electronics. --- ## 3. Implementation (Driving Circuit) Because this is a **transducer** (not an indicator), it does not have internal circuitry to create a tone. You must provide a square wave at the resonant frequency (3.5 kHz) to drive it. ### Basic Driver Example A simple NPN transistor circuit is often used to interface with a Microcontroller (MCU): ```cpp // Example: Driving the ROM-2235P-HD-R with an Arduino/MCU const int buzzerPin = 9; // Connected to the base of the transistor void setup() { pinMode(buzzerPin, OUTPUT); } void loop() { // Generate a 3.5kHz tone (Resonant Frequency) tone(buzzerPin, 3500); delay(500); noTone(buzzerPin); delay(500); } ``` --- ## 4. Typical Applications * **Medical Devices:** Handheld monitors and diagnostic tools. * **Consumer Electronics:** Smart home hubs, tablets, and wearables. * **Industrial:** Alarm systems and status feedback for control panels. * **IoT Devices:** Battery-powered sensors requiring low current consumption.