The **AS04008MS-R** is a high-quality, miniature speaker manufactured by **PUI Audio**. It is part of their "Mobile Series" and is specifically designed for applications where space is limited but audio clarity is essential. --- ## 1. Technical Specifications Below are the primary electronic and physical characteristics of the AS04008MS-R: | Parameter | Specification | | :--- | :--- | | **Speaker Type** | Dynamic, Permanent Magnet | | **Rated Power** | 0.5 Watts | | **Maximum Power** | 0.8 Watts | | **Impedance** | 8 Ohms ± 15% | | **Frequency Range** | 500 Hz ~ 20,000 Hz | | **Sound Pressure Level (SPL)** | 85 dB @ 0.5W, 10cm | | **Dimensions** | 40mm (L) x 40mm (W) x 8.4mm (H) | | **Mounting Type** | Surface Mount / Bracket Mount | --- ## 2. Key Internal Components The AS04008MS-R operates using standard electromagnetic principles, consisting of the following parts: ### A. The Voice Coil A precision-wound copper wire coil attached to the diaphragm. When an electrical signal (AC) passes through the coil, it creates a fluctuating magnetic field. ### B. NdFeB Magnet (Neodymium) This speaker utilizes a high-strength **Neodymium-Iron-Boron** magnet. Neodymium is used because it provides a stronger magnetic field in a smaller footprint compared to traditional ferrite magnets, allowing the speaker to be very thin. ### C. Mylar Diaphragm The cone is typically made of **Mylar (polyester film)**. Mylar is chosen for miniature speakers because it is moisture-resistant, lightweight, and capable of high-frequency reproduction without distorting. ### D. Frame (Housing) The frame is made of a rigid ABS plastic or metal alloy to maintain structural integrity and prevent "buzzing" or rattling during high-excursion audio playback. --- ## 3. Application Use Cases Due to its low profile (8.4mm thickness) and 8-ohm impedance, this part is commonly used in: * **Handheld Devices:** Scanner/PDA audio alerts. * **Security Systems:** Control panels and alarm chimes. * **IoT Devices:** Smart home hubs and voice assistants. * **Medical Instrumentation:** Equipment status beeps and alarms. --- ## 4. Design Considerations * **Polarity:** Ensure the positive (+) and negative (-) terminals are connected correctly to maintain "in-phase" operation, especially if using multiple speakers. * **Enclosure:** To maximize the 85dB SPL, it is recommended to mount the speaker in a sealed or ported enclosure to prevent acoustic short-circuiting (sound waves from the back canceling out waves from the front).