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) Pin Function Description GND Ground Connect to microcontroller GND IN1 Relay 1 Input Active-LOW — pull LOW to activate Relay 1 IN2 Relay 2 Input Active-LOW — pull LOW to activate Relay 2 VCC Logic Power Connect to 5V (or 3.3V if JD-VCC jumper is removed) JD-VCC Jumper Jumper State Behavior ON (default) VCC and JD-VCC are bridged — relay coils share power with logic input. Simple wiring, but no electrical isolation. OFF (removed) VCC and JD-VCC are separated — supply 5V separately to JD-VCC for full isolation. Enables 3.3V logic compatibility. Relay Output Terminals (High-Voltage Side) — Per Channel Terminal Name Description COM Common Connect your load's power line here NO Normally Open Disconnected from COM when relay is OFF; connected when relay is ON NC Normally Closed Connected to COM when relay is OFF; disconnected when relay is ON 🔧 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) Relay Module Pin Arduino Pin GND GND IN1 Digital Pin 4 IN2 Digital Pin 5 VCC 5V 🔌 Wiring — ESP32 / Raspberry Pi (Jumper OFF) Relay Module Pin Connection GND (input header) Microcontroller GND IN1 GPIO pin (e.g., GPIO 4) IN2 GPIO pin (e.g., GPIO 5) VCC (input header) Microcontroller 3.3V JD-VCC External 5V supply (+) GND (relay side) External 5V supply (−) 💻 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 Specification Details Number of Channels 2 Relay Type SPDT (Single Pole Double Throw) Relay Contact Rating (AC) 250V AC / 10A Relay Contact Rating (DC) 30V DC / 10A Coil Voltage 5V DC Coil Current (per relay) Approx. 70 mA Trigger Level Active-LOW (LOW = relay ON) Input Drive Current 15–20 mA per channel Isolation Optocoupler (optical isolation between input and relay coil) Input Connector 1×4 pin header (2.54mm pitch): GND, IN1, IN2, VCC Relay Power Jumper JD-VCC (connects or disconnects VCC from relay coil power) Output Terminals Screw terminals — COM, NO, NC per channel Status Indicators 1 LED per channel (lights when relay is active) Logic Compatibility 5V direct; 3.3V with JD-VCC jumper removed Board Dimensions Approx. 51 × 38 × 18 mm (2.0 × 1.5 × 0.7 inches) L × W × H Mounting Holes 4 (M3) 📦 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