1 Channel EL817/PC817 3-5V Optocoupler Isolation Module

1 Channel EL817/PC817 3-5V Optocoupler Isolation Module provides a safe and effective way to interface low-voltage control circuits with higher-voltage systems by using light-based electrical isolation. This module utilizes the high-performance PC817 or EL817 optocoupler to prevent voltage spikes or noise from damaging sensitive microcontrollers like an Arduino or ESP32. Consequently, it acts as a protective barrier that ensures system stability in electrically noisy environments. The board accepts a 3V to 5V input signal to trigger a secondary output, effectively decoupling the ground planes of two different power systems. Therefore, you should integrate this module into your project whenever you need to switch a high-voltage load using a low-power digital signal without risking your control hardware.

Key Features:

• High Isolation Voltage: The integrated EL817/PC817 provides a physical air gap and optical coupling, offering high-voltage transient protection between the input and output.
• Broad Input Compatibility: This module works seamlessly with 3.3V and 5V logic levels, making it compatible with most modern microcontrollers and PLCs.
• On-board Status Indicator: A dedicated LED lights up when the input signal is active, allowing for quick visual debugging during system setup.
• Signal Inversion/Level Shifting: Users can utilize this module to shift signal levels or invert logic states depending on the wiring configuration.
• Compact Form Factor: The small PCB footprint allows for easy installation in tight enclosures or modular control cabinets.

Technical Specifications:

• Input Trigger Voltage: 3 V to 5 V DC
• Output Maximum Voltage: Up to 35 V DC
• Maximum Output Current: 50 mA
• Isolation Voltage (V_ISO): 5000 V_RMS
• Current Transfer Ratio (CTR): 50% to 600% at I_F = 5mA
• Response Time: ≈ 4 μs (Rise), 3 μs (Fall)
• Operating Temperature: −30°C to +85°C

Mechanical Specifications:

• Optocoupler IC: EL817 or PC817 (DIP-4 package mounted on PCB)
• Connector Type: Screw terminals or pin headers for robust connections
• Board Material: High-quality FR-4 fiberglass PCB
• Mounting: Two 3mm mounting holes for secure mechanical fixing

Dimensions:

• Length: ≈ 36.0 mm
• Width: ≈ 13.0 mm
• Height: ≈ 12.0 mm (including components)
• PCB Thickness: 1.6 mm

Pinout and Wiring:

• IN+ (Input Positive): Connect to the 3.3V-5V control signal from the MCU.
• IN- (Input Negative/GND): Connect to the ground of the control circuit.
• VCC (Output Power): Connect to the positive terminal of the output side power supply (up to 35V).
• OUT (Output Signal): Connect to the load or the next stage of the circuit.
• GND (Output Ground): Connect to the ground of the output side power supply.

Datasheet Reference:

• Download Sharp PC817 Series Optocoupler Datasheet

Commonly Used in:

• Microcontroller Isolation: Protecting GPIO pins from back-EMF when switching inductive loads like small motors.
• PLC Interfacing: Connecting standard industrial 24V sensors to 5V digital logic inputs safely.
• Power Supply Monitoring: Detecting the presence of voltage in high-power circuits without direct electrical contact.

Applications:

• Level Conversion: Converting a 3.3V signal to a 12V or 24V signal for industrial equipment.
• Noise Suppression: Eliminating ground loops in complex audio or data acquisition systems.
• Safe Switch Triggering: Using a low-power tactile button to trigger a high-current transistor or relay.

Equivalent Models:

• TLP521: A common Toshiba equivalent that offers similar current transfer ratios and isolation.
• 4N25 / 4N35: Standard 6-pin optocouplers, however, these require a different footprint and lack the integrated module components.
• LTV-817: Lite-On’s direct equivalent to the PC817 series with identical pinouts and electrical characteristics.

Package Includes:

• 1 x 1 Channel EL817/PC817 3-5V Optocoupler Isolation Module