Optocoupler Isolation Board, PC817 4 Channel, 3.6-30V

🛡️ A 4‑channel PC817 optocoupler isolation board designed for galvanic isolation and voltage‑level interfacing between a control side (MCU/PLC/IoT) and a higher‑voltage / noisier load side. It helps protect sensitive logic, improves noise immunity, and enables safe control of external driver stages (MOSFETs, power transistors, relay drivers, etc.).

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🔍 What it’s for (common use cases)

• Galvanic isolation between 3.3 V / 5 V logic and up to 24–30 V control circuits.
• Noise/EMI reduction when switching inductive loads (relays, motors) via external drivers.
• PLC 24 V interfacing to microcontroller voltage levels.
• Isolated sensor level conversion (e.g., 12 V sensor output to a 5 V system).
• Output logic selection (high‑level / pull‑up vs low‑level / pull‑down) using an onboard jumper.

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⭐ Key features

• 🔌 4 independent channels (one PC817 per channel).
• ⚡ Drive (input) signal voltage: 3.6–24 V.
• ⚙️ Output‑side voltage range: 3.6–30 V.
• 🔁 Pulse signal limit: recommended < 4 kHz (higher frequency control may not work reliably).
• 🎚️ Jumper‑selectable output type: “high potential” (pull‑up) or “pull‑down / low output”.
• 🧩 Input side shares GND, while output channels are electrically independent, enabling multiple output voltages simultaneously (within the board’s limits).

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🧾 Technical specifications

Parameter	Value
Optocouplers	PC817 × 4 (one per channel)
Number of channels	4
Drive (input) signal voltage	3.6–24 V
Output‑side voltage range	3.6–30 V
Max output current	up to 10 mA (load‑dependent; total power is limited)
Pulse frequency	recommended < 4 kHz
Output logic selection	jumper: pull‑up (High) or pull‑down (Low)
Board size	about 48 × 38 mm
Mounting hole spacing	long side ~ 42 mm, short side ~ 32 mm

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📌 Terminals / wiring (general concept)

Exact silkscreen labels can vary by batch, but the concept is typically:

Input side (control)

• GND (common) – common ground for the input side
• IN1…IN4 – control signals (3.6–24 V)

Output side (isolated / controlled)

• OUT1…OUT4 – output channels (up to 3.6–30 V; current is limited)
• Jumper setting determines whether the output behaves as:
  • high‑level (pull‑up) output, or
  • low‑level (pull‑down) output.

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⚠️ Notes for reliable operation

• 🧪 For pulse signals, keep frequency below ~4 kHz.
• 🔥 The 10 mA limit means the board is intended mainly for signal transfer / driving external stages, not powering loads directly.
• 🛠️ For higher power loads, use OUT as a control signal for an external MOSFET/transistor/relay driver, preserving isolation.

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