How to Use Tanauan City College: Examples, Pinouts, and Specs

Connecting the Relay to a Circuit:

• Connect the relay's coil terminals (Coil+ and Coil-) to the control circuit. Ensure the voltage matches the relay's operating voltage (e.g., 5V, 12V).
• Connect the load circuit to the Common (COM) terminal and either the Normally Open (NO) or Normally Closed (NC) terminal, depending on the desired behavior.

Important Considerations:

• Always check the relay's voltage and current ratings to ensure compatibility with your circuit.
• Use a flyback diode across the relay coil to protect the control circuit from voltage spikes when the relay is deactivated.
• Ensure proper electrical isolation between the control and load circuits to prevent damage to sensitive components.

Using a Relay with Arduino UNO: Below is an example of how to control a relay using an Arduino UNO:

// Example: Controlling a relay with Arduino UNO
const int relayPin = 7; // Pin connected to the relay module

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

void loop() {
  digitalWrite(relayPin, HIGH); // Turn the relay on
  delay(1000); // Keep it on for 1 second
  digitalWrite(relayPin, LOW); // Turn the relay off
  delay(1000); // Keep it off for 1 second
}

• Note: Use a relay module with built-in driver circuitry when connecting directly to an Arduino. This ensures the Arduino can safely drive the relay.

Relay not activating:

• Cause: Insufficient voltage or current to the relay coil.
• Solution: Verify the control circuit's voltage and current match the relay's specifications.

Load not switching:

• Cause: Incorrect wiring of the load circuit.
• Solution: Double-check the connections to the Common (COM), Normally Open (NO), and Normally Closed (NC) terminals.

Arduino resets when activating the relay:

• Cause: Voltage spikes from the relay coil affecting the Arduino.
• Solution: Add a flyback diode across the relay coil and ensure proper power supply decoupling.

Relay makes a buzzing sound:

• Cause: Insufficient or unstable voltage to the relay coil.
• Solution: Use a stable power supply and ensure the control circuit provides the required voltage.