The **WSP-12A-R** is a high-performance, water-resistant, ultra-miniature piezo buzzer (transducer) typically used in electronics for audible feedback or alarms. It is widely utilized in handheld devices, medical equipment, and automotive electronics due to its small footprint and environmental protection. --- ### 1. Key Technical Specifications | Parameter | Specification | | :--- | :--- | | **Type** | Piezoelectric Transducer (External Drive) | | **Rated Voltage** | 3.0 Vp-p | | **Operating Voltage** | 1.0 ~ 20.0 Vp-p | | **Resonant Frequency** | 4,000 Hz ± 500 Hz | | **Sound Pressure Level (SPL)** | Min. 75 dB at 10cm / 3Vp-p / 4kHz | | **Current Consumption** | Max. 3 mA | | **Operating Temperature** | -20°C to +70°C | | **Mounting Type** | SMD (Surface Mount Device) | --- ### 2. Functional Components The WSP-12A-R consists of several critical electronic and mechanical parts: #### A. Piezoelectric Ceramic Element This is the heart of the device. It consists of a ceramic disc bonded to a metal diaphragm (usually brass or stainless steel). When an alternating voltage is applied, the ceramic expands and contracts (the inverse piezoelectric effect), causing the diaphragm to vibrate and create sound waves. #### B. Housing and Sound Chamber * **Material:** Liquid Crystal Polymer (LCP) or high-temperature plastic. * **Function:** The internal chamber is acoustically tuned to match the resonant frequency (4kHz) of the piezo element, maximizing the volume (SPL). #### C. Sealing (The "R" Suffix) The "R" in the part number often denotes **Water Resistance** or **Washability**. * It usually features a protective film or potting that prevents water, dust, and flux cleaners (during the soldering process) from entering the sound hole and damaging the internal diaphragm. #### D. SMD Terminals The bottom of the component features gold-plated or tin-plated pads for surface mounting. This allows for automated pick-and-place assembly on PCBs. --- ### 3. Driving Circuit Requirements Unlike an "indicator" (which has internal circuitry), the **WSP-12A-R is a transducer**. It requires an external oscillating signal to produce sound. ```cpp // Example: Arduino Pseudo-code for driving the WSP-12A-R int buzzerPin = 9; void setup() { pinMode(buzzerPin, OUTPUT); } void loop() { // Generate a 4000Hz square wave (Resonant Frequency) tone(buzzerPin, 4000); delay(500); noTone(buzzerPin); delay(500); } ``` --- ### 4. Comparison: Transducer vs. Indicator | Feature | WSP-12A-R (Transducer) | Active Buzzer (Indicator) | | :--- | :--- | :--- | | **Internal Oscillator** | No | Yes | | **Input Signal** | AC/Square Wave | DC Voltage | | **Tone Flexibility** | Can change frequency/pitch | Fixed frequency | | **Circuit Complexity** | Requires driving circuit | Simple On/Off | ---