The **MA25TBD-R** is a specialized electronic component, typically categorized as a **Piezoelectric Diaphragm** or **Piezo Transducer**. It is widely used in applications requiring sound generation, such as alarms, medical devices, and instrumentation. --- ### 1. Technical Specifications Below are the typical characteristics associated with the MA25TBD-R series: | Parameter | Specification (Typical) | | :--- | :--- | | **Component Type** | Piezoelectric Diaphragm (External Drive) | | **Resonant Frequency** | ~2.5 kHz to 4.0 kHz | | **Resonant Impedance** | 500Ω - 1000Ω (Max) | | **Capacitance** | ~20,000 pF to 30,000 pF at 120Hz | | **Diameter** | Approx. 25mm | | **Material** | Brass (Plate) + Piezoceramic (Element) | | **Connection Type** | Red/Black Lead Wires (R suffix) | --- ### 2. Key Internal Components The MA25TBD-R consists of three primary physical layers that allow it to function: 1. **Metal Plate (Substrate):** Usually made of brass or stainless steel. It acts as the structural base and one of the electrodes. 2. **Piezoelectric Ceramic:** A thin layer of ceramic material (like Lead Zirconate Titanate) bonded to the metal plate. 3. **Silver Electrode:** A thin coating on top of the ceramic to allow for the second electrical connection. 4. **Lead Wires:** The "R" in the part number often signifies the presence of **Red and Black wires** pre-soldered to the unit for easy integration. --- ### 3. How it Works (Physics) The device operates on the **Inverse Piezoelectric Effect**: * **Input:** When an alternating voltage (AC) or a square wave is applied to the leads. * **Mechanical Action:** The ceramic layer expands and contracts rapidly. * **Output:** Because the ceramic is bonded to the metal plate, it causes the plate to flex or "bow." This vibration pushes the surrounding air, creating audible sound waves. --- ### 4. Application Circuit Example Since this is an **External Drive** type (it does not have a built-in oscillator), it requires an external circuit to generate sound. ```cpp // Simple Arduino code to drive a Piezo like the MA25TBD-R void setup() { pinMode(9, OUTPUT); // Connect Piezo to Pin 9 } void loop() { tone(9, 2500); // Send 2.5kHz square wave delay(500); // Sound for 0.5 seconds noTone(9); // Silence delay(500); } ``` --- ### 5. Common Use Cases * **Smoke Alarms:** High-decibel output at specific frequencies. * **Handheld Electronics:** "Beep" confirmations for keypresses. * **Industrial Sensors:** Used as a low-cost vibration sensor (Reverse Effect). * **Medical Equipment:** Alert tones for patient monitors.