How to Use 2 channel 12 V relay module: Examples, Pinouts, and Specs

The 2 Channel 12V Relay Module is a versatile electronic component designed to control high-power devices using low-power signals. Each relay on the module can switch devices on and off with a 12V signal, making it ideal for automation and control systems. This module is commonly used in home automation, industrial control, and various DIY projects.

1. Power Supply:

   • Connect the VCC pin to a 5V power supply.
   • Connect the GND pin to the ground of the power supply.

2. Control Signals:

   • Connect the IN1 pin to a digital output pin of a microcontroller (e.g., Arduino).
   • Connect the IN2 pin to another digital output pin of the microcontroller.

3. Load Connections:

   • Connect the device you want to control to the COM1 and NO1/NC1 terminals for Relay 1.
   • Connect another device to the COM2 and NO2/NC2 terminals for Relay 2.

• Ensure that the power supply voltage matches the module's operating voltage (12V DC).
• Use appropriate heat sinks or cooling mechanisms if switching high-power loads.
• Avoid switching loads that exceed the relay's maximum ratings to prevent damage.
• Use optocouplers or isolation circuits if controlling the relay module from sensitive electronics.

/*
  Example code to control a 2 Channel 12V Relay Module using Arduino UNO.
  This code will turn on Relay 1 for 2 seconds, then turn it off and turn on
  Relay 2 for 2 seconds, and repeat the cycle.
*/

const int relay1Pin = 7; // Pin connected to IN1
const int relay2Pin = 8; // Pin connected to IN2

void setup() {
  // Initialize the relay control pins as outputs
  pinMode(relay1Pin, OUTPUT);
  pinMode(relay2Pin, OUTPUT);

  // Ensure relays are off at startup
  digitalWrite(relay1Pin, HIGH);
  digitalWrite(relay2Pin, HIGH);
}

void loop() {
  // Turn on Relay 1
  digitalWrite(relay1Pin, LOW);
  delay(2000); // Wait for 2 seconds

  // Turn off Relay 1
  digitalWrite(relay1Pin, HIGH);

  // Turn on Relay 2
  digitalWrite(relay2Pin, LOW);
  delay(2000); // Wait for 2 seconds

  // Turn off Relay 2
  digitalWrite(relay2Pin, HIGH);
}

1. Relays Not Switching:

   • Ensure the control signals (IN1 and IN2) are correctly connected and receiving the appropriate voltage.
   • Verify that the power supply voltage is 12V DC.

2. Relay Module Overheating:

   • Check if the load exceeds the relay's maximum current rating.
   • Use heat sinks or cooling mechanisms if necessary.

3. Interference with Microcontroller:

   • Use optocouplers or isolation circuits to prevent electrical noise from affecting the microcontroller.

• Check Connections: Ensure all connections are secure and correctly oriented.
• Measure Voltages: Use a multimeter to verify the voltages at the VCC, GND, IN1, and IN2 pins.
• Test Relays Individually: Test each relay separately to isolate the issue.
• Use External Power Supply: If the microcontroller's power supply is insufficient, use an external power supply for the relay module.

By following this documentation, users can effectively integrate the 2 Channel 12V Relay Module into their projects, ensuring reliable and efficient control of high-power devices.