A single-channel optocoupler relay module allows a microcontroller to safely control high-voltage or high-current devices with electrical isolation between the control and load circuits.

Overview and Functionality

A single-channel optocoupler relay module is an interface board that enables low-voltage microcontrollers (like Arduino, ESP32, or Raspberry Pi) to switch high-power AC or DC loads. The optocoupler provides electrical isolation, protecting the microcontroller from voltage spikes and preventing ground loops, which enhances safety and reliability .

Key Specifications

• Control Voltage: Typically 5V DC, configurable for high-level or low-level triggering via a jumper .
• Relay Ratings: Can switch AC 250V at 10A or DC 30V at 10A, suitable for lamps, motors, and other appliances .
• Terminals: Standard screw terminals for COM (common), NO (normally open), and NC (normally closed) connections .
• Driver Current: Requires approximately 15–20mA from the microcontroller to activate the relay .
• Indicators: Onboard LEDs indicate relay activation and power status .

Features and Advantages

• Electrical Isolation: The optocoupler separates the low-voltage control side from the high-voltage load side, reducing risk of damage or shock .
• Configurable Triggering: Can be set to activate on logic high or logic low, making it compatible with various microcontroller logic levels .
• Ease of Use: Plug-and-play design with standard interfaces allows direct connection to microcontrollers without additional circuitry .
• Versatility: Suitable for home automation, robotics, industrial control, and IoT projects .

Applications

• Home Automation: Control lights, fans, or appliances remotely.
• Industrial Automation: Switch motors, solenoids, or other high-power devices.
• Robotics: Operate actuators or high-current components safely.
• IoT Projects: Integrate with smart home systems for remote control and monitoring .

Usage Tips

1. Connect VCC to 5V and GND to the microcontroller ground.
2. Connect the control signal to the input pin, respecting the jumper setting for high/low trigger.
3. Connect the load to COM, NO, or NC terminals according to the desired switching behavior.
4. Ensure the load does not exceed the relay's rated voltage and current.
5. Use the onboard LED indicators to verify proper operation .

This module is ideal for beginners and students due to its simplicity, safety, and compatibility with common microcontrollers while providing reliable control of high-power devices.