1 way electromagnetic relay module low level trigger without optocoupler with light 3.3V

Description

Product Overview

The 1 Way Electromagnetic Relay Module is a simple, cost-effective switching solution designed to control high-power AC or DC loads directly from a 3.3V logic system. Unlike more complex relay modules that incorporate optocoupler isolation, this module uses a direct transistor driver circuit (typically an NPN transistor such as 2N2222 or BC547) to activate the relay coil . This design offers a lower cost and simpler circuit, making it ideal for hobbyist projects, educational use, and applications where isolation is not critical.

Designed with a low-level trigger, the relay activates when the control pin is pulled LOW (0V) and deactivates when pulled HIGH (3.3V) . This active-LOW behavior provides a degree of safety—the relay remains off during power-up or if the control signal is lost, preventing accidental activation of connected devices.

With relay contacts rated for 10A at 250V AC or 10A at 30V DC, this module can control lights, fans, motors, pumps, solenoids, and other household or industrial appliances . An onboard status LED provides visual confirmation when the relay is activated, simplifying operation monitoring and troubleshooting.

Important Note: This module does not include optocoupler isolation. The control circuit and the high-voltage load share a common ground path . Exercise caution when wiring high-voltage loads and ensure proper insulation and clearance for safety .

Key Features

• Low-Level Trigger (Active LOW): Relay activates when the IN pin is pulled LOW (0V) and deactivates when HIGH (3.3V). This design ensures the relay remains off during power-up .

• Direct Transistor Drive: Uses a simple NPN transistor (such as 2N2222, BC547, or S8050) to drive the relay coil, eliminating the need for optocoupler components .

• 3.3V Logic Compatibility: Designed specifically for 3.3V microcontrollers like ESP32, ESP8266, Raspberry Pi Pico, and STM32, with a control signal range of 0V–3.3V .

• 10A High Switching Capacity: SPDT relay contacts rated for 10A at 250V AC or 10A at 30V DC, suitable for controlling lights, fans, motors, pumps, and industrial equipment .

• SPDT Contact Configuration: Provides Common (COM), Normally Open (NO), and Normally Closed (NC) terminals for maximum wiring flexibility—use NO for OFF-by-default operation or NC for ON-by-default operation .

• Status Indicator LED: Onboard LED illuminates when the relay is activated (IN pin LOW), providing clear visual feedback .

• Compact and Lightweight: Small PCB footprint with mounting holes for easy integration into breadboards, enclosures, or control panels .

• Simple 3-Pin Control Interface: Standard 2.54mm pitch header (VCC, GND, IN) allows direct connection to microcontrollers, sensors, or manual switches .

Technical Specifications