The **MA21TAA-R** is a specific model of an **Electromagnetic Buzzer** (also known as a transducer) typically manufactured by companies like **Mallory Sonalert Products**. These components are used to convert electrical signals into audible sound through mechanical vibration. --- ## 1. Technical Specifications The "MA21" series generally follows a standardized set of electronic characteristics designed for industrial and commercial applications. | Parameter | Typical Value / Range | | :--- | :--- | | **Operating Voltage** | 1.5V to 3V DC | | **Rated Voltage** | 2.0V DC | | **Current Consumption** | Max 30mA - 40mA | | **Sound Pressure Level (SPL)** | 80dB to 90dB @ 10cm | | **Resonant Frequency** | 2,000Hz - 2,500Hz | | **Operating Temperature** | -20°C to +70°C | | **Mounting Type** | Through-hole (Pins) | --- ## 2. Key Internal Components The MA21TAA-R operates on the principle of electromagnetism. It contains several critical electronic and mechanical parts: ### A. The Magnetic Coil A fine copper wire wound around a core. When current flows through it, it creates a fluctuating magnetic field. ### B. The Diaphragm A thin metal plate (usually iron or steel) located above the coil. The magnetic field pulls the diaphragm, and when the current is cut, it snaps back. This rapid movement creates sound waves. ### C. Housing (Case) The "TAA" suffix often refers to the specific housing style. It is usually a high-temperature plastic (like PBT or PPS) designed to withstand wave soldering. --- ## 3. Part Number Breakdown (Nomenclature) While manufacturers vary slightly, the code typically breaks down as follows: 1. **MA**: Series identifier (Mallory/Standard series). 2. **21**: Size/Diameter indicator (typically ~12mm to 20mm). 3. **T**: Terminal type (likely Pin/Through-hole). 4. **AA**: Frequency or Voltage rating specific code. 5. **R**: RoHS Compliant (Lead-free). --- ## 4. Driving Circuit Requirements Unlike "Indicators" which beep when DC voltage is applied, **Transducers** like the MA21TAA-R require an external drive circuit (like a square wave) to function. ```python # Conceptual Microcontroller code to drive the buzzer import machine import time buzzer = machine.PWM(machine.Pin(15)) buzzer.freq(2400) # Set to the resonant frequency def beep(): buzzer.duty_u16(32768) # 50% duty cycle time.sleep(0.5) buzzer.duty_u16(0) # Off ``` ---