BDD 1CH 3.3V Relay Module High/Low Level Trigger Optocoupler Board

The BDD Relay Board 1 Channel 3.3V is a compact and reliable relay control module designed for safe and efficient switching of electrical loads in low-voltage control systems. Featuring a high/low level trigger input and built-in optocoupler isolation, this module provides stable performance and enhanced protection for microcontrollers and sensitive electronics.

Engineered for 3.3V logic systems, the relay module allows direct interfacing with popular development platforms such as Arduino, ESP8266, ESP32, Raspberry Pi (via GPIO level shifting), and other embedded controllers. Its flexible trigger configuration supports both active-high and active-low operation, making it suitable for a wide range of applications.

A key feature of this module is its fault-tolerant design, ensuring that the relay remains in a safe state even if the control signal is disconnected or disrupted. This improves system reliability and prevents unintended switching in critical applications.

The relay output section provides standard switching terminals: Normally Open (NO), Normally Closed (NC), and Common (COM). This allows users to control both NO and NC load configurations depending on circuit requirements.

The onboard trigger selection jumper (S1) allows users to easily configure whether the relay activates on a high or low input signal. This flexibility makes it adaptable for different microcontroller logic levels and control schemes.

Key Features

Part Number: BDD Relay Board 1CH 3.3V

1-channel relay output

Operating voltage: 3.3V DC logic control

High-level or low-level trigger selectable

Built-in optocoupler isolation for safe control

Fault-tolerant design for improved safety

Standard NO / NC / COM output terminals

Compatible with microcontrollers and IoT boards

Easy integration into DIY and industrial projects

Stable and reliable switching performance

Relay Interface Description

DC+: Positive power supply input (3.3V)

DC-: Ground connection

IN: Control signal input (high/low trigger)

Output Terminals

NO (Normally Open): Open circuit until relay is activated

NC (Normally Closed): Closed until relay is activated

COM (Common): Shared switching terminal

Trigger Configuration

Jumper S1 selects trigger mode

LOW trigger: Relay activates on LOW signal

HIGH trigger: Relay activates on HIGH signal

Applications

Home automation systems

Microcontroller-based switching circuits

Smart IoT devices

Robotics control systems

LED and lighting control

Motor and solenoid switching (low power)

Industrial signal switching

DIY electronics projects

Security and alarm systems

Embedded system prototyping

Technical Specifications

Model: BDD Relay Board 1 Channel 3.3V

Channels: 1

Control Voltage: 3.3V DC

Trigger Type: High / Low selectable

Isolation: Optocoupler

Output Contacts: NO / NC / COM

Design: Fault-tolerant control system

Interface: Digital IN control pin

Benefits

Safe isolation between control and load circuits

Flexible trigger configuration for different systems

Reliable switching for automation projects

Easy integration with microcontrollers

Compact and durable design

Reduced risk of control line failure

Summary

The BDD 1 Channel 3.3V Relay Module is a versatile and safe switching solution designed for modern embedded systems. With optocoupler isolation, selectable trigger modes, and fault-tolerant operation, it ensures reliable performance in automation, IoT, and electronic control applications while maintaining compatibility with low-voltage microcontroller platforms.

What's in the box
1 x BDD 1CH 3.3V Relay Module High/Low Level Trigger Optocoupler Board