Chip-cn-dat/HLW-dat/HLW8032-dat/HLW8032-ISO-Version-dat/HLW8032-ISO-Version-dat.md
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@@ -36,4 +36,6 @@ Then, use the coefficients K1, K2, and K3 as constants for calculating power, vo
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- [[zeming-dat]]
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-- [[HLW8032-dat]] - [[HLW-dat]]
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+- [[HLW8032-dat]] - [[HLW-dat]]
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+
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+- [[HLW8032-ISO-version]] - [[HLW]]
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Chip-cn-dat/HLW-dat/hlw-dat.md
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| ! chip | Sensing | Size | Calibration | COMM | Other |
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| ------- | ----------------------- | ------- | ----------- | -------- | ---------------------------- |
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-| HLW8112 | 2x current / 1x voltage | SSOP16 | No need | SPI/UART | OV / LV / Zeor-crossing / OC |
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-| HLW8032 | Example | Example | | | |
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-| HLW8012 | Example | Example | | | |
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+| [[HLW8112-dat]] | 2x current / 1x voltage | SSOP16 | No need | SPI/UART | OV / LV / Zeor-crossing / OC |
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+| [[HLW8032-dat]] | Example | Example | | | |
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+| [[HLW8012-dat]] | Example | Example | | | |
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- http://www.hiliwi.com
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* [[HLW8012-dat]] - [[HLW8032-dat]]
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-
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+- [[SVC1031-dat]] - [[SVC1035-dat]] - [[OPM1126-dat]]
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## code repo
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## ref
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-- [[HLW]]
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+- [[HLW]] - [[HLW8032]]
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Chip-dat/toshiba-dat/PC817-dat/PC817-dat.md
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# PC817-dat
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-- [[PC817]]
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+
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+
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+## PIN 4 current-limit resistor
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+
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+### 🔌 Understanding Pin 4
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+- **Pin 4** is the **collector** of the phototransistor inside the PC817.
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+- Typically connected to **Vcc** through a **pull-up resistor**.
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+- **Pin 3** (emitter) is usually connected to **ground**.
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+- When the internal LED is ON, the transistor conducts and pulls Pin 4 low.
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+
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+---
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+
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+### 📐 Key Factors to Consider
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+1. **Vcc voltage level** (e.g., 3.3V or 5V)
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+2. **Desired output current** from the transistor (1–20 mA typical)
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+3. **Speed requirement** (lower resistance = faster switching)
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+4. **Input requirements** of the following stage (e.g., microcontroller)
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+
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+---
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+
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+### ⚙️ General Pull-Up Resistor Range
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+| Vcc | Recommended Pull-Up Resistor |
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+|------|------------------------------|
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+| 5V | 2.2kΩ – 10kΩ (default: 4.7kΩ) |
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+| 3.3V | 1kΩ – 4.7kΩ (default: 2.2kΩ) |
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+
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+---
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+
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+### 🧮 Optional Calculation (Ohm’s Law)
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+
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+```text
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+R = (Vcc - Vce(sat)) / Ic
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+```
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+
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+- Vce(sat) ≈ 0.2V (when transistor is ON)
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+- Ic = desired collector current (e.g., 1 mA)
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+
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+**Example for 5V system:**
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+
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+```text
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+R = (5V - 0.2V) / 0.001A = 4.8kΩ → Use 4.7kΩ standard value
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+```
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+
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+---
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+
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+### ✅ Summary
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+- **Use 4.7kΩ** for 5V as a safe default.
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+- Choose **lower resistance** for faster switching.
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+- Choose **higher resistance** for lower power consumption.
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+
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+
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+
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+## ref
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+
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+- [[PC817]]
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+
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+- [[optical-coupler-dat]]
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Tech-dat/Optical-Coupler-DAT/Optical-Coupler-DAT.md
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@@ -37,6 +37,8 @@ The EL357 has a **wider operating temperature range**, which may be beneficial i
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![](2025-05-29-16-00-18.png)
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+
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+
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## ref
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- [[tech-dat]]
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