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

The 4-channel relay module (5V JD-VCC) is a versatile electronic component designed to control high-power devices such as lights, motors, and appliances using low-power control signals from a microcontroller. This module features four independent relays, each capable of switching AC or DC loads. The JD-VCC pin allows for the isolation of the relay power supply from the control signal, improving safety and reducing electrical noise.

• Home automation systems (e.g., controlling lights, fans, or appliances)
• Industrial automation for switching high-power devices
• Robotics and IoT projects requiring control of multiple devices
• Motor control and power distribution in embedded systems

• Operating Voltage: 5V DC
• Relay Channels: 4
• Relay Type: SPDT (Single Pole Double Throw)
• Maximum Load (per relay):
  • AC: 250V at 10A
  • DC: 30V at 10A
• Trigger Voltage: 3.3V to 5V (compatible with most microcontrollers)
• Isolation: Optocoupler isolation for improved safety
• Dimensions: Approximately 75mm x 55mm x 20mm
• Indicator LEDs: One LED per relay to indicate activation status

The module has two sets of pins: control pins and power pins. Additionally, each relay has three output terminals.

1. Power the Module:

   • Connect the JD-VCC pin to a 5V power supply for the relay coils.
   • Connect the VCC pin to a 5V power supply for the control circuit.
   • Connect the GND pin to the ground of your microcontroller or power supply.

2. Control Signals:

   • Connect the IN1, IN2, IN3, and IN4 pins to the digital output pins of your microcontroller.
   • When a control pin is set to LOW, the corresponding relay will activate.

3. Connecting Loads:

   • For each relay, connect the device you want to control to the COM and NO or NC terminals, depending on whether you want the device to be normally off or on.

4. Jumper Configuration:

   • If you want to use a single power supply for both the control circuit and the relay coils, leave the jumper cap in place.
   • For separate power supplies, remove the jumper cap and connect JD-VCC to a dedicated 5V source.

• Ensure the total current drawn by the relays does not exceed the power supply's capacity.
• Use optocoupler isolation (enabled by JD-VCC) to protect your microcontroller from electrical noise.
• Avoid switching loads that exceed the relay's maximum ratings to prevent damage.
• Use flyback diodes across inductive loads (e.g., motors) to suppress voltage spikes.

// Example code to control a 4-channel relay module with Arduino UNO
// Ensure the relay module's VCC and GND are connected to the Arduino's 5V and GND

#define RELAY1 2  // Define pin 2 for Relay 1
#define RELAY2 3  // Define pin 3 for Relay 2
#define RELAY3 4  // Define pin 4 for Relay 3
#define RELAY4 5  // Define pin 5 for Relay 4

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

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

void loop() {
  // Example sequence to toggle relays
  digitalWrite(RELAY1, LOW); // Turn ON Relay 1
  delay(1000);               // Wait for 1 second
  digitalWrite(RELAY1, HIGH); // Turn OFF Relay 1

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

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

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

1. Relays Not Activating:

   • Ensure the JD-VCC and VCC pins are properly powered.
   • Verify that the control signals (IN1–IN4) are set to LOW to activate the relays.

2. Electrical Noise or Unstable Operation:

   • Use separate power supplies for JD-VCC and VCC to isolate the relay coils from the control circuit.
   • Add decoupling capacitors (e.g., 100µF) near the power supply pins.

3. Relay Clicking but Load Not Switching:

   • Check the wiring of the load to the COM, NO, and NC terminals.
   • Ensure the load does not exceed the relay's maximum ratings.

4. Arduino Resetting When Relays Activate:

   • This may occur due to insufficient power supply. Use a separate power source for JD-VCC.

Q: Can this module be used with a 3.3V microcontroller?
A: Yes, the module is compatible with 3.3V control signals, but ensure the relays are powered with 5V.

Q: What is the purpose of the jumper cap?
A: The jumper cap connects VCC and JD-VCC for shared power. Remove it to use separate power supplies.

Q: Can I control AC devices with this module?
A: Yes, the relays can switch AC loads up to 250V at 10A. Ensure proper insulation and safety precautions.