12V 8 Channel Relay Module Board For Arduino Raspberry Pi

12V 8-Channel Relay Module with Optocoupler – Low Level Trigger

Product Description

The 12V 8-Channel Relay Module with Optocoupler is a multi-channel relay board designed to control multiple AC or DC electrical loads using a microcontroller or development board. It features 8 independent relay channels with optocoupler isolation, providing reliable switching and improved protection between the control circuit and load section.

The module uses high-current relays capable of switching up to 250V AC at 10A or 30V DC at 10A. Each channel provides NO, COM, and NC contacts, allowing flexible control of normally open and normally closed circuits.

The relay inputs use active-low triggering, making the module easy to interface with popular development platforms. Onboard relay indicator LEDs provide visual feedback when individual channels are activated. The module also includes screw terminals for convenient and secure load connections.

With four mounting holes and a standard control interface, this relay board is suitable for robotics, home automation, industrial control prototypes, Arduino projects, and other applications requiring multiple electrical outputs.

Features

• 8-channel relay module
• 12V relay operation
• Optocoupler isolation
• Low-level trigger inputs
• High-current relay contacts
• Supports up to 250V AC / 10A
• Supports up to 30V DC / 10A
• Independent NO, COM, and NC contacts
• Relay status indicator LEDs
• Convenient screw terminal connections
• Standard interface for development boards
• Four mounting holes for easy installation
• Double-sided FR-4 PCB construction
• Suitable for 51/AVR/ARM and other controller platforms
• 100% function and stability tested

Specifications

Parameter	Specification
Product Type	8-Channel Relay Module
Relay Channels	8
Relay Voltage	12V DC
Trigger Type	Low Level / Active Low
Isolation	Optocoupler
AC Switching Rating	250V AC @ 10A
DC Switching Rating	30V DC @ 10A
Control Supply	5V DC
Control Inputs	IN1 – IN8
Output Contacts	NO, COM, NC
PCB Material	FR-4
Terminal Type	KF301 Screw Terminal
Mounting Holes	4
Mounting Hole Diameter	3.1 mm
Mounting Hole Pitch	131 × 49.5 mm
Module Dimensions	138 × 56 × 18.5 mm
Weight	Approximately 120 g

Pin Configuration

Pin	Function
VCC	5V control power supply
GND	Ground
IN1	Relay Channel 1 trigger
IN2	Relay Channel 2 trigger
IN3	Relay Channel 3 trigger
IN4	Relay Channel 4 trigger
IN5	Relay Channel 5 trigger
IN6	Relay Channel 6 trigger
IN7	Relay Channel 7 trigger
IN8	Relay Channel 8 trigger

Relay Output Configuration

Each relay channel provides three output terminals:

Terminal	Function
NO1 – NO8	Normally Open contacts
COM1 – COM8	Common relay contacts
NC1 – NC8	Normally Closed contacts

When the relay is inactive, COM is connected to NC. When the relay is activated, COM switches to NO.

Design and Construction

The module is built using a double-sided FR-4 PCB designed for reliable electrical and mechanical performance. Eight relays are arranged on the board along with optocouplers, driver circuitry, indicator LEDs, and screw terminals.

The blue KF301 screw terminals provide secure and convenient connections for the controlled loads. Four mounting holes allow the module to be securely installed inside enclosures, control panels, robotic systems, and other project structures.

The optocoupler-based control section helps provide electrical isolation between the input/control circuitry and relay switching section, improving resistance to electrical interference.

Working Principle

The module receives control signals through IN1–IN8. Each input independently controls its corresponding relay channel. The inputs are active low, so applying a LOW signal to an input activates the associated relay.

When a relay is activated, its indicator LED turns on and the relay changes its contact state. The COM and NO contacts become connected, allowing the connected load to operate.

When the relay is released, COM returns to its NC connection. This allows each channel to be configured for either normally open or normally closed switching depending on the application.

Usage

1. Connect the module’s control supply to the appropriate power source.
2. Connect VCC to 5V and GND to the power supply ground.
3. Connect the controller’s output pins to IN1–IN8.
4. Use the appropriate NO, COM, or NC terminals to connect the loads.
5. Apply a LOW-level trigger to the required input to activate its relay.
6. Check the corresponding LED to confirm relay activation.

Applications

• Arduino automation projects
• Raspberry Pi control systems
• Home automation
• Industrial automation prototypes
• Multi-load switching
• Lighting control
• Fan control
• Pump control
• Motor control
• Solenoid control
• Robotics
• IoT projects
• Smart control panels
• Electrical appliance switching
• DIY electronics
• Educational projects

Compatible Platforms

• Arduino
• 51 microcontrollers
• AVR
• ARM
• Raspberry Pi
• ESP32
• ESP8266
• STM32
• Other compatible microcontroller and development boards

Package Includes

• 1 × 12V 8-Channel Relay Module with Optocoupler

Product Disclaimer

The relay contact ratings indicate the maximum specified switching capacity and may vary depending on the type of load. Motors, pumps, transformers, and other inductive loads can generate switching transients and may require additional protection.

The control interface uses 5V power, while the relays are rated for 12V operation as specified. Verify the power connections and module configuration before use.

High-voltage AC connections can be hazardous. Use suitable insulation, wiring, fusing, and electrical safety precautions when working with mains-powered loads.

Product images are for representation only. The actual product may differ slightly in appearance, colour, component placement, or terminal configuration depending on the manufacturing batch.