LR7843 MOSFET Control Relay Module - Solid State Relay (SSR) Replacement

The LR7843 is a high-performance MOSFET-based control relay module designed as a solid-state relay (SSR) replacement for traditional mechanical relays. Featuring the LR7843 transistor and IRF843 MOSFET, this module provides reliable, fast switching for DC loads with PWM control capability, making it ideal for Arduino projects, motor control, LED dimming, and automation applications.

Key Features:

• LR7843 transistor with IRF843 MOSFET for high-current switching
• Solid-state relay (SSR) design - no mechanical parts
• PWM control input for variable speed/brightness control
• Optoisolator (PC817) for electrical isolation and protection
• Wide DC power supply range: 6-28VDC
• Screw terminal connectors for easy wiring
• Compact PCB design with clear labeling
• LED indicator for load status
• Compatible with Arduino, Raspberry Pi, and other microcontrollers

Technical Specifications:

• Main Component: LR7843 + IRF843 MOSFET
• Power Supply Voltage: 6-28VDC
• Control Signal: PWM (3.3V/5V compatible)
• Isolation: PC817 optoisolator
• Load Type: DC motors, LED strips, resistive loads
• Switching Speed: High-speed solid-state switching
• Terminal Type: Screw terminals (Blue/Green)
• PCB Color: Black
• Dimensions: Compact module design

Pin Configuration:

• Power Supply: + (Positive), - (Negative/Ground)
• Load Connection: Load Power (+/-), Load Ground
• Control Signal: PWM (Signal Input), GND (Ground)
• Clear labeling on PCB for easy connection

Circuit Features:

• Optoisolator isolation for microcontroller protection
• MOSFET IRF843 for high-current load switching
• Built-in flyback diode for inductive load protection
• Resistor network for proper biasing (4.7K, 100Ω, 1.7K)
• LED indicator with current-limiting resistor
• Professional PCB layout with HY-532 designation

Applications:

• DC motor speed control with PWM
• LED strip dimming and control
• Solenoid and relay replacement
• Arduino and Raspberry Pi projects
• Automation and robotics
• Power switching applications
• Variable load control
• DIY electronics projects

Wiring Diagram Included:

• Complete circuit schematic showing connections
• DC power supply connection (6-28VDC)
• Motor/load connection diagram
• PWM control signal from Arduino/microcontroller
• Optoisolator isolation circuit
• Ground connections clearly marked

Advantages Over Mechanical Relays:

• No mechanical wear - longer lifespan
• Silent operation - no clicking sound
• Faster switching speed
• PWM compatible for variable control
• No contact bounce
• Lower power consumption

Package Includes:

• 1 x LR7843 MOSFET Control Relay Module
• Screw terminal connectors (pre-installed)

Compatibility:

• Arduino (Uno, Mega, Nano, etc.)
• Raspberry Pi
• ESP8266/ESP32
• STM32 and other microcontrollers
• 3.3V and 5V logic levels
• DC motors, LED strips, solenoids, and other DC loads