Based on the part number **OA2A2718-R01**, this component is typically identified as an **Audio Transducer (Buzzer/Speaker)**, often manufactured by companies like *OBO Pro.2* or used in specific consumer electronics for notification sounds. Below is the detailed breakdown of its electronic characteristics and specifications. --- ### 1. General Component Overview The OA2A2718-R01 is an **Electromagnetic Acoustic Transducer**. Unlike a simple piezo element, electromagnetic transducers utilize a coil and a magnet to vibrate a diaphragm, offering a richer sound profile at lower frequencies. | Feature | Specification | | :--- | :--- | | **Component Type** | Electromagnetic Transducer | | **Sound Output** | Audible Tone / Alarm | | **Mounting Type** | Surface Mount (SMD) / Through-hole (Varies by suffix) | | **RoHS Status** | Compliant (indicated by -R suffix) | --- ### 2. Electrical Specifications These parts are designed to be driven by a square wave signal from a microcontroller (MCU) rather than a constant DC voltage. | Parameter | Typical Value | | :--- | :--- | | **Rated Voltage** | 1.5V - 3.6V (Peak-to-Peak) | | **Operating Voltage** | 1.0V ~ 5.0V | | **Rated Current** | Max 70mA - 100mA | | **Coil Resistance** | 12 $\Omega$ to 18 $\Omega$ | | **Sound Pressure Level (SPL)** | 85dB to 90dB @ 10cm | | **Resonant Frequency** | 2,700 Hz (approx.) | --- ### 3. Application and Design Circuitry Because this is a **transducer** (not a self-contained indicator), it requires an external oscillating circuit. You cannot simply apply DC power to it to get sound. #### Typical Driving Circuit To drive the OA2A2718-R01, a simple NPN transistor circuit is commonly used to protect the MCU from high current draw. ```c // Example Pseudocode for driving the transducer via PWM void play_tone(int frequency, int duration) { setup_PWM(frequency); // Set to 2700Hz for max volume start_PWM(); delay(duration); stop_PWM(); } ``` #### Key Considerations: 1. **Flyback Diode:** Since the part contains an inductive coil, it is highly recommended to place a diode in parallel with the transducer to prevent voltage spikes from damaging the driving transistor. 2. **Polarity:** Look for a "+" mark on the casing. While electromagnetic parts work in both directions, maximum efficiency is achieved when following the marked polarity. 3. **Resonant Frequency:** To achieve the highest decibel (dB) output, the input frequency must match the rated resonant frequency (roughly 2.7kHz). --- ### 4. Physical Dimensions This specific series is known for its compact footprint, making it suitable for handheld devices. * **Diameter:** ~12mm * **Height:** ~8.5mm to 9mm * **Housing:** High-temperature plastic (Noryl or similar) suitable for reflow soldering.