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 applications where you need to control high-voltage or high-current devices such as lights, motors, and other electrical appliances. This module is commonly used in home automation, industrial automation, and various DIY projects.

1. Power Supply:

   • Connect the VCC pin to a 12V DC 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 your microcontroller (e.g., Arduino).
   • Connect the IN2 pin to another digital output pin of your 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 operating voltage of the relay module (12V DC).
• Use appropriate flyback diodes across the relay coils to protect your microcontroller from voltage spikes.
• Avoid exceeding the maximum switching voltage and current ratings to prevent damage to the relays.
• Use proper insulation and safety measures when dealing with high-voltage AC loads.

/*
 * Example code to control a 2 Channel 12V Relay Module using Arduino UNO.
 * This code will alternately switch the relays on and off every second.
 */

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

void setup() {
  // Initialize the relay control pins as outputs
  pinMode(relay1Pin, OUTPUT);
  pinMode(relay2Pin, OUTPUT);
  
  // Initially turn off both relays
  digitalWrite(relay1Pin, HIGH); // Relay is active low
  digitalWrite(relay2Pin, HIGH); // Relay is active low
}

void loop() {
  // Turn on Relay 1 and turn off Relay 2
  digitalWrite(relay1Pin, LOW);  // Activate Relay 1
  digitalWrite(relay2Pin, HIGH); // Deactivate Relay 2
  delay(1000); // Wait for 1 second
  
  // Turn off Relay 1 and turn on Relay 2
  digitalWrite(relay1Pin, HIGH); // Deactivate Relay 1
  digitalWrite(relay2Pin, LOW);  // Activate Relay 2
  delay(1000); // Wait for 1 second
}

1. Relays Not Activating:

   • Ensure that the VCC and GND pins are properly connected to a 12V DC power supply.
   • Verify that the control signals (IN1 and IN2) are receiving the correct voltage levels from the microcontroller.

2. Microcontroller Resetting:

   • This could be due to voltage spikes caused by the relay coils. Use flyback diodes across the relay coils to mitigate this issue.

3. Load Not Switching:

   • Check the connections to the COM, NO, and NC terminals.
   • Ensure that the load does not exceed the maximum switching voltage and current ratings of the relay.

• Double-check Wiring: Ensure all connections are secure and correctly placed.
• Use Flyback Diodes: Place diodes across relay coils to protect the microcontroller from voltage spikes.
• Check Power Supply: Make sure the power supply provides a stable 12V DC output.
• Test Relays Individually: Isolate and test each relay to ensure they are functioning correctly.

By following this documentation, you should be able to effectively use the 2 Channel 12V Relay Module in your projects, ensuring reliable control of high-power devices with low-power signals.