The **CSS-314S** is a professional-grade, miniature high-performance **Magnetic Buzzer/Transducer** commonly used in electronics for audible feedback. It is manufactured by companies like CUI Devices (now Same Sky). --- ### 1. Key Technical Specifications Below are the primary electronic characteristics of the CSS-314S: | Parameter | Specification | | :--- | :--- | | **Type** | Magnetic Transducer | | **Rated Voltage** | 3.0 Vp-p | | **Operating Voltage** | 2.0 ~ 5.0 Vp-p | | **Rated Current** | Max 70 mA | | **Sound Pressure Level (SPL)** | Min 85 dB (at 10cm) | | **Resonant Frequency** | 2,730 Hz | | **Coil Resistance** | 15 ± 3 Ω | | **Mounting Type** | Surface Mount (SMD) | --- ### 2. Electronic Components & Structure The CSS-314S is a **transducer**, not an indicator. This means it does not have internal driving circuitry. To function, it requires an external oscillating signal. * **Coil (Electromagnet):** A copper winding with a DC resistance of approximately 15 Ohms. When current passes through, it creates a magnetic field. * **Permanent Magnet:** Provides a static magnetic field that interacts with the coil's field. * **Diaphragm:** A thin metal plate that vibrates rapidly when the electromagnetic field fluctuates, creating sound waves. * **SMD Housing:** High-temperature plastic (LCP) designed to withstand SMT reflow soldering processes. --- ### 3. Application Circuitry Because this is a magnetic transducer, you must drive it with a square wave at its resonant frequency (2,730 Hz) for maximum volume. #### Typical Driver Circuit A simple NPN transistor or MOSFET is usually used to switch the buzzer: ```text VCC (3V - 5V) | [Buzzer CSS-314S] | +----[Flyback Diode (1N4148)]---- (Parallel to Buzzer) | [Collector/Drain of Transistor] | [Emitter/Source to Ground] ``` **Note:** Always include a **flyback diode** in parallel with the buzzer. Since the buzzer contains a coil (inductor), it can generate high-voltage spikes when switched off, which might damage your microcontroller or transistor. --- ### 4. Comparison: Transducer vs. Indicator | Feature | CSS-314S (Transducer) | Built-in Indicator | | :--- | :--- | :--- | | **Drive Signal** | Requires PWM/Square Wave | Requires constant DC | | **Frequency Control** | Variable (Adjustable pitch) | Fixed pitch | | **Complexity** | Higher (Needs external oscillating circuit) | Low (Plug and play) |