Tech-dat/MCU-dat/8051-dat/8051-dat.md
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# 8051-dat
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+- [[MCU-dat]]
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The official name of the 8051 microcontroller is Intel MCS-51.
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It was introduced by Intel in 1980 as a part of their MCS (Microcontroller Set) family. Over time, the 8051 architecture became popular and was adopted by many manufacturers, often with enhancements and additional features. Examples of such variants include Atmel's AT89 series and Silicon Labs' 8051-based microcontrollers.
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+
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+## flash
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+
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+- [[DPR1088-dat]]
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+
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## Chips
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- [[n76e003-dat]]
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- [[STC89C52-dat]]
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-- [[STC-dat]] - [[stc15w202s-dat]]
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+- [[STC-dat]] - [[stc15w202s-dat]]
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+## AT89
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+
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+- AT89S51
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+- AT89S52
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+- AT89S53
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+- AT89S8252
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+
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+- AT89C55WD
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+
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+
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+## ref
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+
Tech-dat/acturator-dat/speaker-dat/2026-03-03-21-13-02.png
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Tech-dat/acturator-dat/speaker-dat/speaker-dat.md
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## Cavity Speakers (Box Speakers)
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+![](2026-03-03-21-13-02.png)
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A **Cavity Speaker** (often called a "Box Speaker" in electronics) is not a different type of speaker driver, but rather a **complete acoustic system**. It consists of a standard speaker driver pre-installed into a precisely engineered, sealed plastic or metal enclosure (the "cavity").
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Think of it as a professional, miniature version of a bookshelf speaker designed to fit inside compact devices like smartphones, laptops, or your DIY projects.
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| **Protection** | Membrane is exposed to dust/damage | Fully protected inside the box |
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| **Complexity** | You must calculate "air volume" yourself | Acoustic tuning is done by the factory |
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+## cavity speaker types
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+
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+- 商品型号：3718腔体喇叭_8欧2瓦_带线2P_2.0
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+- 产品类型：腔体喇叭
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+- 封装尺寸：3718带线2P_2.0
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+- 阻抗：8欧
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+- 功率：2瓦
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+- 工作频率：0-20KHz
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+- 输出声压：95±3dB
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+
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+more
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+
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+| Model | diaphragm | Size (mm) | Impedance | Power | Connector |
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+| ----- | --------- | --------- | --------- | ----- | --------------- |
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+| 2415 | | 24x15 | 8Ω | 1W | Wired 2P 1.25mm |
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+| 3020 | | 30x20 | 4Ω | 3W | Wired 2P 1.25mm |
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+| 3020 | | 30x20 | 8Ω | 2W | Wired 2P 1.25mm |
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+| 3525 | | 35x25 | 4Ω | 3W | Wired 2P 1.25mm |
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+| 3525 | | 35x25 | 8Ω | 2W | Wired 2P 1.25mm |
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+| 3020 | | 30x20 | 4Ω | 3W | Wired 2P 2.0mm |
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+| 3020 | | 30x20 | 8Ω | 2W | Wired 2P 2.0mm |
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+| 3525 | | 35x25 | 4Ω | 3W | Wired 2P 2.0mm |
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+| 3525 | | 35x25 | 8Ω | 2W | Wired 2P 2.0mm |
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+| 2828 | | 28x28 | 4Ω | 2W | Wired 2P 1.25mm |
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+| 2828 | | 28x28 | 4Ω | 2W | Wired 2P 2.0mm |
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+| 2828 | | 28x28 | 4Ω | 3W | Wired 2P 1.25mm |
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+| 2828 | | 28x28 | 4Ω | 3W | Wired 2P 2.0mm |
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+| 2831 | | 28x31 | 4Ω | 3W | Wired 2P 1.25mm |
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+| 2831 | | 28x31 | 4Ω | 3W | Wired 2P 2.0mm |
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+| 2831 | | 28x31 | 4Ω | 3W | Wired 2P Dupont |
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+| 4014 | | 40x14 | 4Ω | 2W | Wired 2P 2.54mm |
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+| 4014 | | 40x14 | 8Ω | 2W | Wired 2P 2.54mm |
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+| 3718 | | 37x18 | 8Ω | 2W | Wired 2P 2.0mm |
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+| 5318 | | 53x18 | 8Ω | 2W | Wired 2P 2.0mm |
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+| 3070 | | 30x70 | 8Ω | 3W | Wired 2P 2.0mm |
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+| 3370 | | 33x70 | 8Ω | 3W | Wired 2P 2.0mm |
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+| 3080 | | 30x80 | 8Ω | 3W | Wired 2P 2.0mm |
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+| 6423 | | 64x23 | 8Ω | 2W | Wired 2P 2.0mm |
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+| 45100 | | 45x100 | 8Ω | 5W | Wired 2P 2.0mm |
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+| 45100 | dual | 45x100 | 8Ω | 5W | Wired 2P 2.0mm |
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+| 3718 | | 37x18 | 8Ω | 2W | Wired 4P 2.0mm |
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+| 5318 | | 53x18 | 8Ω | 2W | Wired 4P 2.0mm |
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+| 3070 | | 30x70 | 8Ω | 3W | Wired 4P 2.0mm |
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+| 3370 | | 33x70 | 8Ω | 3W | Wired 4P 2.0mm |
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+| 3080 | | 30x80 | 8Ω | 3W | Wired 4P 2.0mm |
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+| 6423 | | 64x23 | 8Ω | 2W | Wired 4P 2.0mm |
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+| 45100 | | 45x100 | 8Ω | 5W | Wired 4P 2.0mm |
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+| 45100 | dual | 45x100 | 8Ω | 5W | Wired 4P 2.0mm |
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+## audio impedance
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+Impedance (Z)?
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+In electronics, **Impedance** (symbol: $Z$) is the total opposition that a circuit presents to alternating current (AC). It combines basic resistance ($R$) with "reactance" ($X$), which depends on the frequency of the signal.
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+For your ESP32-S3 and robotics projects, impedance plays four critical roles:
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+---
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+### 1. Power Transfer & Efficiency
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+In audio systems, matching the impedance of your **amplifier** to your **speaker** is vital.
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+* **The Rule:** Your MAX98357A amplifier is rated for specific loads (usually $4\Omega$ or $8\Omega$).
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+* **Low Impedance ($4\Omega$):** Draws more current. The speaker will be louder, but the amplifier will run hotter and consume more battery.
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+* **High Impedance ($8\Omega$):** Draws less current. The system is more stable and produces less heat, but the maximum volume is lower.
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+
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+---
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+
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+### 2. Circuit Protection (Current Limiting)
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+Impedance acts like a "throttle" for electricity.
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+* If you connect a device with **$0\Omega$ impedance** (a short circuit) to an ESP32 GPIO, the current will spike instantly and burn the internal transistors.
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+* By choosing components with the correct impedance (or adding resistors), you ensure the current stays within the ESP32's safe limit of **20mA to 40mA**.
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## 4-ohm and 8-ohm