How to Use 1 Channel 5V Relay Module: Examples, Pinouts, and Specs

The 1 Channel 5V Relay Module is an electronic component designed to allow a low-voltage control signal (e.g., from a microcontroller) to switch a higher voltage circuit. This module is widely used in applications where electrical isolation and control of high-power devices are required. It is ideal for controlling devices such as lights, fans, motors, and other appliances.

• Home automation systems
• Industrial control systems
• IoT projects for switching high-power devices
• Motor control in robotics
• Smart lighting systems

The following are the key technical details of the 1 Channel 5V Relay Module:

The module has a total of 6 pins and terminals, as described below:

1. Power the Module: Connect the VCC pin to a 5V DC power supply and the GND pin to the ground.
2. Control Signal: Connect the IN pin to a digital output pin of a microcontroller (e.g., Arduino UNO). The relay will activate when the control signal is HIGH.
3. Connect the Load:
   • Connect the device you want to control (e.g., a light bulb) to the COM and NO terminals if you want it to turn on when the relay is activated.
   • Alternatively, connect the device to the COM and NC terminals if you want it to turn off when the relay is activated.
4. Isolation: Ensure proper electrical isolation between the low-voltage control circuit and the high-voltage load circuit.

• Safety First: Always ensure the high-voltage side of the circuit is properly insulated to avoid electric shock.
• Current Rating: Do not exceed the maximum current rating of 10A to prevent damage to the relay.
• Flyback Diode: If controlling an inductive load (e.g., a motor), use a flyback diode across the load to protect the relay from voltage spikes.
• Logic Level Compatibility: Ensure the control signal voltage matches the relay's trigger voltage (3.3V or 5V).

Below is an example of how to use the 1 Channel 5V Relay Module with an Arduino UNO to control a light bulb.

• Connect the relay module's VCC to the Arduino's 5V pin.
• Connect the relay module's GND to the Arduino's GND pin.
• Connect the relay module's IN pin to Arduino digital pin 7.
• Connect the light bulb to the COM and NO terminals of the relay module.
• Connect the other side of the light bulb to the AC power supply.

// Define the relay control pin
const int relayPin = 7;

void setup() {
  // Set the relay pin as an output
  pinMode(relayPin, OUTPUT);
  
  // Ensure the relay is off at startup
  digitalWrite(relayPin, LOW);
}

void loop() {
  // Turn the relay on (light bulb ON)
  digitalWrite(relayPin, HIGH);
  delay(5000); // Keep the light on for 5 seconds
  
  // Turn the relay off (light bulb OFF)
  digitalWrite(relayPin, LOW);
  delay(5000); // Keep the light off for 5 seconds
}

1. Relay Not Activating:

   • Cause: Insufficient control signal voltage.
   • Solution: Ensure the IN pin receives a voltage of at least 3.3V (logic HIGH).

2. Load Not Switching:

   • Cause: Incorrect wiring of the load to the relay terminals.
   • Solution: Double-check the connections to the COM, NO, and NC terminals.

3. Relay Clicking but No Output:

   • Cause: Faulty relay or insufficient power supply.
   • Solution: Verify the power supply voltage and current. Replace the relay if necessary.

4. Indicator LED Not Lighting Up:

   • Cause: No power to the module or damaged LED.
   • Solution: Check the VCC and GND connections. Replace the module if the LED is damaged.

Q1: Can I use this relay module with a 3.3V microcontroller like the ESP8266?
A1: Yes, the relay module can be triggered with a 3.3V control signal. Ensure the VCC pin is still powered with 5V.

Q2: Can I control DC devices with this relay?
A2: Yes, the relay can switch DC devices as long as the voltage does not exceed 30V and the current does not exceed 10A.

Q3: Is the relay module safe for switching high-power AC devices?
A3: Yes, but ensure proper insulation and follow safety guidelines when working with high-voltage circuits.