How to Use 4 channel relay module 5V JD-VCC: Examples, Pinouts, and Specs

The 4 Channel Relay Module 5V JD-VCC is an electronic component designed to control up to four independent devices using low-power control signals. It operates on a 5V power supply and features an optocoupler-based isolation mechanism, ensuring safe and reliable operation in automation and control systems. The JD-VCC pin allows the relay power to be isolated from the control signal, reducing electrical noise and protecting sensitive microcontrollers.

• Home automation systems (e.g., controlling lights, fans, or appliances)
• Industrial automation and control
• Robotics and IoT projects
• Switching high-power devices (e.g., motors, pumps) with low-power microcontrollers
• Smart home projects integrated with Arduino, Raspberry Pi, or other microcontrollers

• Operating Voltage (Control Signal): 5V DC
• Relay Voltage (JD-VCC): 5V DC
• Trigger Current (per channel): 15-20mA
• Relay Type: SPDT (Single Pole Double Throw)
• Maximum Load (per channel):
  • AC: 250V at 10A
  • DC: 30V at 10A
• Optocoupler Isolation: Yes
• Number of Channels: 4
• Dimensions: Approximately 75mm x 55mm x 20mm
• Indicator LEDs: One per channel (lights up when the relay is active)

The module has two sets of pins: control pins and relay output terminals.

Each relay has three output terminals:

1. Power the Module:

   • Connect the VCC pin to a 5V power supply and GND to ground.
   • For isolated operation, connect a separate 5V power supply to JD-VCC and remove the jumper cap.

2. Connect the Control Signals:

   • Connect the IN1, IN2, IN3, and IN4 pins to the digital output pins of a microcontroller (e.g., Arduino).
   • The relays are triggered by a LOW signal (0V).

3. Connect the Load:

   • For each relay, connect the device you want to control to the NO, NC, and COM terminals as needed.
   • Example: For a light bulb, connect one wire to COM and the other to NO.

4. Write the Control Code:

   • Use the microcontroller to send LOW signals to the IN pins to activate the relays.

• Isolation: For better safety and noise reduction, use a separate power supply for JD-VCC and remove the jumper cap.
• Inductive Loads: When switching inductive loads (e.g., motors), use a flyback diode across the load to prevent voltage spikes.
• Current Ratings: Ensure the connected load does not exceed the relay's maximum current and voltage ratings.
• Active LOW Trigger: Remember that the relays are activated by a LOW signal, not HIGH.

// Example code to control a 4 Channel Relay Module with Arduino UNO
// This code toggles each relay ON and OFF with a 1-second delay.

#define RELAY1 2  // Connect IN1 to digital pin 2
#define RELAY2 3  // Connect IN2 to digital pin 3
#define RELAY3 4  // Connect IN3 to digital pin 4
#define RELAY4 5  // Connect IN4 to digital pin 5

void setup() {
  // Set relay pins as OUTPUT
  pinMode(RELAY1, OUTPUT);
  pinMode(RELAY2, OUTPUT);
  pinMode(RELAY3, OUTPUT);
  pinMode(RELAY4, OUTPUT);

  // Initialize all relays to OFF (HIGH state)
  digitalWrite(RELAY1, HIGH);
  digitalWrite(RELAY2, HIGH);
  digitalWrite(RELAY3, HIGH);
  digitalWrite(RELAY4, HIGH);
}

void loop() {
  // Turn each relay ON and OFF with a delay
  digitalWrite(RELAY1, LOW);  // Relay 1 ON
  delay(1000);                // Wait 1 second
  digitalWrite(RELAY1, HIGH); // Relay 1 OFF

  digitalWrite(RELAY2, LOW);  // Relay 2 ON
  delay(1000);                // Wait 1 second
  digitalWrite(RELAY2, HIGH); // Relay 2 OFF

  digitalWrite(RELAY3, LOW);  // Relay 3 ON
  delay(1000);                // Wait 1 second
  digitalWrite(RELAY3, HIGH); // Relay 3 OFF

  digitalWrite(RELAY4, LOW);  // Relay 4 ON
  delay(1000);                // Wait 1 second
  digitalWrite(RELAY4, HIGH); // Relay 4 OFF
}

1. Relays Not Activating:

   • Cause: Insufficient power supply or incorrect wiring.
   • Solution: Ensure the VCC and JD-VCC pins are connected to a stable 5V power source. Check the GND connection.

2. Microcontroller Resets When Relays Activate:

   • Cause: Voltage spikes or insufficient power supply.
   • Solution: Use a separate power supply for JD-VCC and remove the jumper cap. Add a capacitor across the power supply to stabilize it.

3. Relay LED Lights Up, but Load Does Not Switch:

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

4. Relays Stay ON or OFF Unexpectedly:

   • Cause: Electrical noise or floating input pins.
   • Solution: Use pull-up or pull-down resistors on the IN pins to stabilize the control signals.

• Can I use this module with a 3.3V microcontroller?

  • Yes, but you may need a level shifter or transistor to ensure the control signals are compatible with the 5V relays.

• What happens if I exceed the relay's current rating?

  • Exceeding the current rating can damage the relay contacts and cause overheating. Always stay within the specified limits.

• Can I control AC and DC loads simultaneously?

  • Yes, as long as each load is connected to a separate relay and does not exceed the relay's ratings.

• Is the module safe for high-voltage applications?

  • The module is designed for high-voltage applications, but proper insulation and safety precautions must be followed.