How to Use 5V 30A 1- Channel Relay Module With Optocoupler High/Low Level Trigger: Examples, Pinouts, and Specs

The 5V 30A 1-Channel Relay Module manufactured by SONGLE (Part ID: RELAY MODULE) is a versatile electronic component designed to control high-voltage devices using low-voltage signals. It features an optocoupler for electrical isolation, ensuring safe operation and protection of sensitive control circuits. This module supports both high-level and low-level triggering, making it adaptable to a wide range of applications.

• Home automation systems (e.g., controlling lights, fans, or appliances)
• Industrial automation and control
• IoT projects requiring high-voltage device control
• Robotics and motor control
• Smart home projects with microcontrollers like Arduino, Raspberry Pi, or ESP32

The following table outlines the key technical details of the relay module:

The relay module has the following pins and terminals:

1. Power the Module: Connect the VCC pin to a 5V DC power supply and the GND pin to ground.
2. Connect the Load:
   • For devices that should turn ON when the relay is active, connect the load between the COM and NO terminals.
   • For devices that should turn OFF when the relay is active, connect the load between the COM and NC terminals.
3. Control Signal:
   • Connect the IN pin to the control signal from a microcontroller or other control circuit.
   • Ensure the control signal matches the trigger mode (high-level or low-level) configured on the module.
4. Optional Isolation:
   • If electrical isolation is required, remove the jumper between VCC and JD-VCC.
   • Provide a separate 5V power supply to JD-VCC for the relay coil.

• Electrical Isolation: Use the optocoupler feature to protect sensitive control circuits from high-voltage spikes.
• Load Ratings: Ensure the connected load does not exceed the module's maximum ratings (250V AC / 30V DC, 30A).
• Trigger Mode: Verify the trigger mode (high or low) before connecting the control signal.
• Flyback Diode: For inductive loads (e.g., motors), use a flyback diode across the load to prevent voltage spikes.
• Secure Connections: Ensure all connections are tight and insulated to prevent short circuits.

Below is an example of how to control the relay module using an Arduino UNO:

// Example: Controlling a 5V Relay Module with Arduino UNO
// This code toggles the relay ON and OFF every 2 seconds.

#define RELAY_PIN 7  // Define the pin connected to the relay module's IN pin

void setup() {
  pinMode(RELAY_PIN, OUTPUT);  // Set the relay pin as an output
  digitalWrite(RELAY_PIN, LOW); // Start with the relay OFF (LOW level trigger)
}

void loop() {
  digitalWrite(RELAY_PIN, HIGH); // Turn the relay ON
  delay(2000);                   // Wait for 2 seconds
  digitalWrite(RELAY_PIN, LOW);  // Turn the relay OFF
  delay(2000);                   // Wait for 2 seconds
}

Note: Adjust the RELAY_PIN definition to match the Arduino pin connected to the relay module.

1. Relay Not Activating:

   • Cause: Insufficient power supply or incorrect wiring.
   • Solution: Ensure the VCC pin is connected to a stable 5V power source and the GND pin is properly grounded.

2. Load Not Responding:

   • Cause: Incorrect wiring of the load to the relay terminals.
   • Solution: Verify the load is connected to the correct terminals (COM, NO, or NC) based on the desired behavior.

3. Microcontroller Not Triggering the Relay:

   • Cause: Mismatch between the control signal and the trigger mode.
   • Solution: Check the trigger mode (high-level or low-level) and ensure the control signal matches.

4. Relay Clicking but No Output:

   • Cause: Faulty relay or damaged module.
   • Solution: Test the relay with a multimeter or replace the module if necessary.

Q1: Can I use this relay module with a 3.3V microcontroller like ESP32?
A1: Yes, the module supports high-level triggers as low as 3.0V, making it compatible with 3.3V logic.

Q2: Is it safe to control AC appliances with this module?
A2: Yes, but ensure proper insulation and follow safety guidelines when working with high-voltage AC loads.

Q3: Can I use this module to control multiple devices?
A3: No, this is a single-channel relay module. For multiple devices, use a multi-channel relay module.

Q4: What is the purpose of the optocoupler?
A4: The optocoupler provides electrical isolation between the control circuit and the high-voltage load, protecting sensitive components.

Q5: How do I change the trigger mode?
A5: The module typically includes a jumper or solder pads to configure the trigger mode. Refer to the module's datasheet for specific instructions.