2-Channel 5V SPDT Power Relay Module with Optocoupler Isolation — 250V/10A — Arduino, ESP32, Raspberry Pi Compatible

📋 Overview

The 2-Channel 5V Relay Module with Optocoupler Isolation lets you safely control high-voltage or high-current devices — such as lamps, fans, heaters, pumps, solenoid locks, and motors — from a low-voltage microcontroller like an Arduino, ESP32, or Raspberry Pi. Each channel features an SPDT (Single Pole Double Throw) relay rated for up to 250V AC / 10A or 30V DC / 10A, with onboard optocouplers that electrically isolate the relay coil circuit from your microcontroller for added safety and noise protection.

This version features a 4-pin input header (GND, IN1, IN2, VCC) and a JD-VCC jumper that lets you choose between shared power (simple wiring) or fully isolated operation (separate relay power supply). The relays are active-LOW — they turn ON when the input signal is pulled LOW. LED indicators show the activation state of each channel at a glance.

⭐ Key Features

• 2 independent relay channels — each with its own optocoupler-isolated input and LED status indicator
• SPDT relay contacts — COM, NO (Normally Open), and NC (Normally Closed) screw terminals per channel
• High-power switching — rated for 250V AC / 10A or 30V DC / 10A per channel
• Optocoupler isolation — electrically separates your microcontroller from the relay coil circuit, preventing ground loops and protecting sensitive electronics from voltage spikes
• JD-VCC jumper — leave on for simple shared-power wiring, or remove for full electrical isolation with a separate 5V relay supply
• 3.3V and 5V logic compatible — works directly with 5V Arduino boards; supports 3.3V logic (ESP32, Raspberry Pi) when JD-VCC jumper is removed
• Active-LOW trigger — relay activates when input pin is pulled LOW (15–20 mA per channel)
• Screw terminals — secure, tool-tightened connections for high-voltage / high-current output wiring
• 4 mounting holes — M3 holes for secure installation in enclosures or project frames

📌 Pinout Reference

Input Header (4-Pin, Low-Voltage Side)

JD-VCC Jumper

Relay Output Terminals (High-Voltage Side) — Per Channel

🔧 JD-VCC Jumper Explained

The JD-VCC jumper is what makes this module more versatile than basic relay boards. It controls whether the relay coils share power with your microcontroller or run from a separate supply.

Jumper ON — Simple Wiring (No Isolation)

With the jumper in place, just connect VCC to your Arduino's 5V pin and GND to GND. The relay coils draw power from the same 5V rail as your microcontroller. This is the easiest setup but offers no electrical isolation.

Jumper OFF — Full Isolation

Remove the jumper and connect a separate 5V power supply to JD-VCC and the relay-side GND. The VCC pin on the input header now only powers the optocoupler LEDs and can run at 3.3V — making this mode essential for ESP32, Raspberry Pi, and other 3.3V boards.

🔌 Wiring — Arduino (Jumper ON)

🔌 Wiring — ESP32 / Raspberry Pi (Jumper OFF)

💻 Sample Arduino Code

This sketch toggles each relay on and off. Remember: LOW = relay ON, HIGH = relay OFF (active-LOW logic).

// 2-Channel Relay Module — Basic Toggle Example
// Active-LOW: LOW = ON, HIGH = OFF

const int relay1 = 4;
const int relay2 = 5;

void setup() {
  pinMode(relay1, OUTPUT);
  pinMode(relay2, OUTPUT);
  digitalWrite(relay1, HIGH);  // Start OFF
  digitalWrite(relay2, HIGH);  // Start OFF
  Serial.begin(9600);
  Serial.println("2-Channel Relay Test");
}

void loop() {
  digitalWrite(relay1, LOW);   // Relay 1 ON
  Serial.println("Relay 1: ON");
  delay(2000);

  digitalWrite(relay1, HIGH);  // Relay 1 OFF
  Serial.println("Relay 1: OFF");
  delay(1000);

  digitalWrite(relay2, LOW);   // Relay 2 ON
  Serial.println("Relay 2: ON");
  delay(2000);

  digitalWrite(relay2, HIGH);  // Relay 2 OFF
  Serial.println("Relay 2: OFF");
  delay(2000);
}

📊 Specifications

📦 What's in the Box

• 1x 2-Channel 5V Relay Module with Optocoupler Isolation (JD-VCC jumper pre-installed)

🔌 Compatible With

• Arduino Uno, Mega, Nano, Leonardo, and other 5V Arduino boards
• ESP32 and ESP8266 (3.3V — remove JD-VCC jumper, use separate 5V relay supply)
• Raspberry Pi (3.3V GPIO — remove JD-VCC jumper, use separate 5V relay supply)
• STM32, Teensy, and other 3.3V/5V microcontrollers
• PLC and industrial control interfaces with 5V logic outputs

🎯 Typical Applications

• Home automation — control lights, fans, appliances, and door locks
• IoT projects — remote switching via Wi-Fi (ESP32/ESP8266) or Bluetooth
• 3D printers & CNC machines — control heated beds, spindles, or cooling fans
• Robotics — switch motors, solenoids, and pneumatic valves
• Automotive — control 12V accessories like LED light bars or auxiliary equipment
• Aquarium & greenhouse automation — timed control of pumps, lights, heaters, and ventilation

⚠️ Important Notes

• Mains voltage is dangerous. If switching AC mains (110V/220V), ensure all high-voltage wiring is properly insulated and enclosed. Never touch exposed terminals when the circuit is energized. If you are not experienced with mains wiring, consult a qualified electrician.
• Do not exceed the relay's rated current. For continuous loads, derate to 7–8A to extend relay life and reduce heat buildup.
• Inductive loads (motors, solenoids, transformers) generate voltage spikes when switched. Add a flyback diode (DC loads) or snubber circuit (AC loads) across the load to protect the relay contacts.
• Relay activates on power-up? GPIO pins may float LOW during microcontroller boot. Add a 10 kΩ pull-up resistor from each input pin to VCC, and in your code, set the pin HIGH before configuring it as an output.
• This module is not UL/CE certified for permanent mains installations. It is intended for prototyping, hobby, and educational use.

📄 Documentation & Resources

• 📘 2-Channel 5V Relay Module User Guide — complete setup guide with wiring diagrams, JD-VCC jumper explanation, sample code, and troubleshooting
• 🔗 All Power & Switching Component User Guides