The **PT-266-R** is an electronic component primarily classified as a **Piezoelectric Audio Transducer** (Buzzer). It is commonly used in consumer electronics, medical devices, and industrial alarms to provide acoustic feedback or warning signals. --- ### 1. Technical Specifications Below are the typical electrical and physical characteristics associated with the PT-266-R series: | Parameter | Specification | | :--- | :--- | | **Transducer Type** | Piezoelectric | | **Operating Voltage** | 1 ~ 30 Vp-p (Max) | | **Rated Voltage** | 3.0 ~ 5.0 Vp-p | | **Current Consumption** | 2 ~ 5 mA (at rated voltage) | | **Sound Pressure Level (SPL)** | 80 ~ 90 dB at 10cm | | **Resonant Frequency** | 4,000 Hz (Typical) | | **Operating Temperature** | -20°C to +70°C | | **Mounting Type** | Through-hole (Pins) | --- ### 2. Core Electronic Components The device is not a "mechanical" bell but an electronic solid-state component consisting of: * **Piezoelectric Ceramic Disc:** The heart of the part. When an oscillating voltage is applied, the ceramic material expands and contracts (the inverse piezoelectric effect), creating sound waves. * **Metal Diaphragm:** A thin brass or stainless steel plate attached to the ceramic disc that amplifies the vibrations into audible sound. * **Housing/Case:** Usually made of PBT (Polybutylene Terephthalate) or ABS plastic, designed with a resonant chamber to focus the sound output. * **Lead Pins:** Tin-plated brass pins for PCB integration. --- ### 3. Operational Requirements Unlike an "indicator" (which makes sound as soon as DC power is applied), the PT-266-R is a **transducer**. This means: 1. **External Circuitry Required:** It does not have a built-in internal oscillator. 2. **Square Wave Input:** To produce sound, the user must provide a PWM (Pulse Width Modulation) signal or a square wave from a microcontroller (like an Arduino or ESP32). 3. **Frequency Control:** The pitch of the sound can be changed by adjusting the frequency of the input signal. --- ### 4. Typical Applications * **User Interface:** Beeps for button presses on appliances. * **Alarms:** Low-battery warnings or error alerts. * **Timers:** Completion signals for ovens or laboratory equipment.