PC817 Optocoupler (Opto-Isolator IC)

PC817 Optocoupler (Opto-Isolator IC)

The PC817 Optocoupler is a widely used isolation component that transfers electrical signals between two circuits using light, providing excellent electrical isolation. It consists of an internal infrared LED and a phototransistor, making it ideal for protecting low-voltage circuits from high-voltage spikes and noise.

Key Features

• Optical Isolation – Electrically isolates input and output circuits
• Infrared LED + Phototransistor – Reliable signal transfer using light
• High Voltage Isolation – Typically up to 5kV isolation
• Compact DIP Package – Easy to use in through-hole designs
• Low Power Consumption – Efficient operation
• Fast Switching – Suitable for digital signal isolation

Applications

• Microcontroller Protection – Isolate Arduino/ESP32 from high voltage
• SMPS & Power Supplies – Feedback and regulation circuits
• Signal Isolation – Noise reduction in communication lines
• Industrial Control Systems – Safe interfacing
• Relay & Switching Circuits – Control high-power loads

Technical Specifications

• Model: PC817
• Type: Optocoupler (Opto-isolator)
• Input: Infrared LED
• Output: Phototransistor
• Isolation Voltage: ~5kV (typical)
• Forward Voltage (LED): ~1.2V
• Collector-Emitter Voltage: Up to 80V
• Current Transfer Ratio (CTR): ~50%–600% (variant dependent)
• Package: DIP-4

Product Example

PC817 Optocoupler IC (DIP-4 Package)
A reliable isolation component for protecting and interfacing electronic circuits.

Why Choose PC817?

• Simple and effective isolation solution
• Widely used and easily available
• Protects sensitive electronics
• Compact and easy to integrate
• Suitable for both analog and digital signals

⚠️ Important Notes

• Requires current-limiting resistor for input LED
• Output is not a perfect logic level — may need pull-up resistor
• Switching speed is moderate (not for very high-speed signals)
• CTR varies between batches — design accordingly
• Ensure correct pin configuration before use