4-Channel 5V SPDT Power Relay Module — 250V/10A — Arduino, ESP32, Raspberry Pi Compatible

📋 Overview

This 4-channel 5V relay module lets you control up to four high-power AC or DC loads directly from a microcontroller like an Arduino, Raspberry Pi, or ESP32. Each channel uses a Single-Pole Double-Throw (SPDT) relay rated for 250V AC at 10A, giving you access to both Normally Open (NO) and Normally Closed (NC) contacts for flexible wiring options.

This is the direct-drive model without optocoupler isolation. It features a simple 6-pin input header (GND, VCC, IN1–IN4) and uses active low logic — pull a control pin LOW to energize the relay. Each channel has a red status LED that lights up when its relay is activated. Just connect your microcontroller's digital output pins and you're ready to switch loads.

⭐ Key Features

• 4 Independent Channels — Control up to four separate high-power devices from a single module
• SPDT Relay Contacts — Each relay provides COM, NO (Normally Open), and NC (Normally Closed) terminals
• 250V AC / 10A Switching — Each channel handles up to 250V AC at 10A, 125V AC at 15A, or 30V DC at 10A
• Active Low Inputs — Pull the input pin LOW to activate the relay, compatible with most microcontrollers
• 5V Control Logic — Powered and controlled directly from a 5V microcontroller — no external relay power supply needed
• LED Status Indicators — Each channel has a red LED that illuminates when the relay is activated
• Simple 6-Pin Interface — Single input header with GND, VCC, IN1, IN2, IN3, IN4 for easy wiring
• Screw Terminals — Secure, tool-tightened connections for high-power load wiring
• Mounting Holes — Four 3.1mm mounting holes for secure installation

📊 Specifications

📌 Pinout

Input Header (6-Pin)

Output Terminals (Per Relay Channel)

🔧 How It Works

This module uses active low logic:

• Input pin HIGH (5V or floating): Relay is OFF — the NO contact is open (disconnected from COM)
• Input pin LOW (0V / GND): Relay is ON — the NO contact closes (connects to COM), and the channel's red LED lights up

Each relay is a Single-Pole Double-Throw (SPDT) switch. When the relay is OFF, COM connects to NC. When the relay is ON, COM switches to NO. You'll hear an audible "click" when the relay switches — this is completely normal.

🔌 Wiring to Arduino

To connect a load to a relay channel, wire one side of your power source to the COM terminal, run a wire from the NO terminal to your load, and complete the circuit from the load back to the power source.

🔋 Power

This module is powered entirely from the 5V VCC pin. There is no separate relay power supply pin or jumper on this model.

If you experience unreliable switching or microcontroller resets, use an external 5V power supply (500 mA+) for the module and share a common GND with your microcontroller.

📦 What's in the Box

• 1x 5V 4-Channel SPDT Power Relay Module

Jumper wires, microcontroller, and mounting hardware are not included.

🛒 What You'll Need

• Microcontroller — Arduino Uno, Mega, Nano, ESP32, Raspberry Pi, or similar 5V-compatible board
• Jumper wires — Female-to-male or male-to-male depending on your setup
• 5V power supply — Recommended if running all four relays simultaneously (500 mA or more)
• Load and power source — The AC or DC device you want to switch, along with its power source

🔌 Compatible With

• Arduino Uno, Mega, Nano, Leonardo, and other 5V Arduino boards
• Raspberry Pi (via 5V pin and GPIO — Pi GPIO is 3.3V, may need level shifting)
• ESP32 / ESP8266 (3.3V logic — test reliability or use a level shifter)
• STM32, PIC, AVR, ARM, MSP430, and other 5V-compatible microcontrollers

🎯 Typical Applications

• Home Automation — Control lights, fans, heaters, and appliances from a microcontroller or IoT platform
• Irrigation Systems — Switch solenoid valves for automated watering schedules
• Industrial Control — Activate motors, pumps, or solenoids in automation projects
• IoT Projects — Combine with Wi-Fi modules (ESP8266/ESP32) for remote appliance control
• Robotics — Control high-power motors or actuators from a low-power controller
• Automotive — Switch 12V accessories like lights, horns, or cooling fans
• Security Systems — Control door locks, alarms, or sirens

⚠️ Important Notes

• No optocoupler isolation: The control inputs connect directly to the relay driver transistors without galvanic isolation. Electrical noise from relay coils or high-voltage loads could potentially affect your microcontroller. For applications where isolation is critical, consider the optocoupler-isolated version.
• Active Low operation: LOW = ON, HIGH = OFF. If your relays seem to work "backwards," check that you're using the correct logic in your code.
• Not suitable for PWM or rapid switching: Mechanical relays have a limited lifespan (~100,000 cycles) and ~10ms switching speed. For high-speed switching, use solid-state relays or MOSFETs.
• Maximum ratings are absolute maximums: For long-term reliability, operate at no more than 80% of rated current (8A at 250V AC).
• 3.3V microcontrollers: This module is designed for 5V logic. Reliable operation at 3.3V is not guaranteed — test thoroughly or use a logic level shifter.
• High-voltage safety: This module can switch mains-level AC voltages. Always disconnect power before making or changing high-voltage connections. If you are not experienced with high-voltage wiring, consult a qualified electrician.

📄 Documentation & Resources

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