How to Use 3 Channel Relay 5V: Examples, Pinouts, and Specs

The Yongli 5V Relay 3 C is a 3-channel relay module designed for interfacing high-voltage devices with low-voltage microcontroller systems like Arduino, Raspberry Pi, or PIC. Each channel can control a separate device, making it suitable for a variety of applications such as home automation, industrial controls, and hobbyist projects.

• Home automation systems
• Remote control of AC/DC motors
• Switching of high-power LEDs
• Control of pumps, fans, and other electrical appliances

• Operating Voltage: 5V DC
• Relay Maximum Switching Voltage: 250V AC / 30V DC
• Relay Maximum Switching Current: 10A (AC) / 10A (DC)
• Number of Channels: 3
• Control Signal: TTL Logic
• Isolation: Opto-isolated inputs

1. Connect the VCC pin to a 5V power supply.
2. Connect the GND pin to the ground of the power supply.
3. Connect the IN1, IN2, and IN3 pins to the digital output pins of a microcontroller.
4. Connect the device you want to control to the NO or NC and COM pins of the relay.

• Ensure the power supply does not exceed 5V as it may damage the relay module.
• Do not exceed the maximum switching voltage and current ratings of the relays.
• Use flyback diodes when controlling inductive loads to prevent back EMF damage.
• Always ensure proper isolation when working with high-voltage circuits.

// Define relay control pins
const int relay1 = 2;
const int relay2 = 3;
const int relay3 = 4;

void setup() {
  // Set relay pins as outputs
  pinMode(relay1, OUTPUT);
  pinMode(relay2, OUTPUT);
  pinMode(relay3, OUTPUT);
}

void loop() {
  // Turn on relay 1
  digitalWrite(relay1, HIGH);
  delay(1000); // Wait for 1 second
  // Turn off relay 1
  digitalWrite(relay1, LOW);
  delay(1000); // Wait for 1 second
  
  // Repeat for relay 2 and 3
  digitalWrite(relay2, HIGH);
  delay(1000);
  digitalWrite(relay2, LOW);
  delay(1000);
  
  digitalWrite(relay3, HIGH);
  delay(1000);
  digitalWrite(relay3, LOW);
  delay(1000);
}

• Relay not activating: Check the input signal and power connections.
• Intermittent operation: Ensure solid connections and no loose wires.
• Overheating: Do not exceed the rated current and voltage.

• Verify that the 5V power supply is stable and within tolerance.
• Check for proper grounding in your circuit.
• Use a multimeter to confirm the control signal from the microcontroller.
• Ensure that the load does not exceed the relay's maximum ratings.

Q: Can I control the relay module with a 3.3V microcontroller?

A: Yes, but ensure that the 3.3V signal is sufficient to trigger the relay. Check the module's datasheet for the minimum input signal voltage.

Q: Is it safe to control AC devices with this relay module?

A: Yes, as long as you do not exceed the maximum voltage and current ratings and ensure proper isolation and safety precautions.

Q: Can I use PWM to control the relay?

A: No, relays require a stable HIGH or LOW signal to switch states. PWM is not suitable for relay control.

Remember to always follow safety guidelines when working with electronics, especially when controlling high-voltage devices.