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

Control high-voltage or high-current devices -- lamps, fans, heaters, pumps, motors, and solenoid locks -- safely from a low-voltage microcontroller. This 2-channel relay module features onboard optocouplers that electrically isolate your microcontroller from the relay coil circuit, and a JD-VCC jumper that lets you choose between simple shared-power wiring or fully isolated operation with 3.3V logic support. Each SPDT relay is rated for up to 250V AC / 10A or 30V DC / 10A.

⚠️ Active-LOW Logic: These relays turn ON when the input pin is pulled LOW. Set your output pins HIGH in setup() to prevent relays from activating during microcontroller boot.

🔧 How It Works

When the input pin is HIGH (or floating), the relay is OFF -- the COM terminal is connected to NC (Normally Closed).
When you pull the input pin LOW, current flows through the optocoupler LED, which triggers the relay driver on the isolated side.
The relay coil energizes, pulling the internal armature from NC to NO (Normally Open) -- you'll hear a distinct "click."
When the input goes HIGH again, the coil de-energizes and the spring returns the contact to NC.

The optocoupler transmits the signal optically -- no direct electrical connection between your microcontroller and the relay coil circuit. This prevents voltage spikes from damaging your microcontroller and eliminates ground loop issues.

⚡ 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 250V AC / 10A or 30V DC / 10A per channel
Optocoupler isolation -- electrically separates your microcontroller from the relay coil circuit
JD-VCC jumper -- leave on for simple shared-power wiring, or remove for full isolation with separate 5V relay supply
3.3V and 5V logic compatible -- works directly with 5V boards; supports 3.3V logic (ESP32, Raspberry Pi) when JD-VCC jumper is removed
Active-LOW trigger -- relay activates when input is pulled LOW (15–20 mA per channel)
Screw terminals -- secure connections for high-voltage / high-current output wiring
4 mounting holes (M3) -- for secure installation in enclosures or project frames

📐 Specifications

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)

USB cable, power supply, jumper wires, and microcontroller are not included.

🛒 What You'll Need

Microcontroller -- Arduino, ESP32, Raspberry Pi, or any 3.3V/5V board with digital GPIO pins
Jumper wires -- female-to-male or female-to-female for connecting the 4-pin input header
5V power supply (optional) -- required only if removing the JD-VCC jumper for fully isolated operation
USB cable -- for programming your microcontroller (type depends on your board)

🔌 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

💡 JD-VCC Jumper Tip: Leave the jumper ON for simple Arduino projects (shared 5V power, no isolation). Remove the jumper for ESP32 or Raspberry Pi projects -- connect a separate 5V supply to JD-VCC and the relay-side GND, then connect VCC on the input header to your board's 3.3V output.

⚠️ 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 may activate on power-up. GPIO pins can float LOW during microcontroller boot. Add a 10 kΩ pull-up resistor from each input pin to VCC, and set pins HIGH before configuring them as outputs in your code.
This module is not UL/CE certified for permanent mains installations. It is intended for prototyping, hobby, and educational use.

🏪 About Envistia Mall

Envistia Mall is a US-based electronics retailer specializing in development boards, sensors, modules, and components for makers, engineers, and educators. We ship from the United States with fast handling times. Product documentation and technical support are available at our dedicated support site.

📦 Fast Free US Shipping | 🔄 Hassle-Free Returns | 📧 Responsive Customer Support

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