The **MAH28FAA-R** is an ultra-small, high-performance **Piezoelectric Ceramic Buzzer (Transducer)** typically manufactured by companies like **Mallory Sonalert Products**. It is designed for applications where space is at a premium and low power consumption is critical. --- ## 1. Technical Specifications Below are the typical electrical and physical parameters for this component: | Parameter | Specification | | :--- | :--- | | **Technology** | Piezoelectric (Requires external drive circuit) | | **Operating Voltage** | 1.0 to 20.0 Vp-p | | **Resonant Frequency** | 4,000 Hz ± 500 Hz | | **Sound Pressure Level (SPL)** | ~75 dB @ 10cm (at 3Vp-p, 4kHz) | | **Current Consumption** | < 1 mA (Typical at 3Vp-p) | | **Capacitance** | ~10,000 pF ± 30% | | **Operating Temp** | -20°C to +70°C | | **Mounting Type** | Surface Mount (SMD) | --- ## 2. Key Features ### A. Piezoelectric Construction Unlike magnetic buzzers that use a coil and magnet, the MAH28FAA-R uses a ceramic disk that deforms when an electric field is applied. * **Low Current:** It draws significantly less power than magnetic versions, making it ideal for battery-operated devices. * **Thin Profile:** The SMD design allows it to be integrated into slim consumer electronics. ### B. "External Drive" Requirement The **R** suffix often denotes that this is a **Transducer**, not an Indicator. * **Indicator:** Has internal circuitry; you apply DC voltage, and it beeps. * **Transducer (MAH28FAA-R):** Requires an AC or square wave signal at its resonant frequency (4kHz) to produce sound. This allows the designer to control the pitch and tone. --- ## 3. Circuit Integration To use this part, you typically need a simple transistor driver circuit or a direct connection to a Microcontroller (MCU) PWM pin. ```cpp // Example: Driving the buzzer with an Arduino-style PWM int buzzerPin = 9; // Connect to the gate of a MOSFET/Transistor void setup() { pinMode(buzzerPin, OUTPUT); } void loop() { tone(buzzerPin, 4000); // Send 4kHz square wave delay(500); noTone(buzzerPin); delay(500); } ``` --- ## 4. Common Applications * **Wearables:** Smartwatches and fitness trackers. * **Medical Devices:** Handheld glucose meters or portable monitors. * **Mobile Electronics:** Confirmation tones for keypads or touchscreens. * **Alarms:** Low-battery alerts in smoke detectors or IoT sensors.