MOSFET FR120N Control Module (Solid-State Relay Replacement Board)
Take control of your high-speed switching circuits and eliminate mechanical failure points with the industrial-grade MOSFET FR120N Control Module. Specifically engineered as a high-performance, solid-state replacement for traditional mechanical relays, this module utilizes an advanced optocoupler-isolated metal-oxide-semiconductor field-effect transistor circuit to manage heavy direct-current loads with absolute precision and zero physical wear.
Unlike traditional electromagnetic relays that suffer from slow response times, noisy contact clicking, and electrical degradation over time, this solid-state alternative operates entirely electronically. With built-in optical isolation, it completely shields your sensitive microcontrollers from high-voltage spikes on the load side. It serves as the definitive choice for automated industrial actuators, high-frequency Pulse Width Modulation motor drivers, custom CNC machinery, and smart agricultural systems.
Key Features
Full Optical Logic Isolation: Features an onboard optocoupler chip that isolates the control signal input side from the high-power load grid, ensuring that inductive feedback spikes never reach your master microcontroller.
Perfect Mechanical Relay Upgrade: Eliminates audible switching noise, mechanical bounce, and contact sparking, allowing the module to achieve an almost infinite operational lifetime.
High-Frequency PWM Control Loop: Responds instantly to digital Pulse Width Modulation signals, making it perfect for precision duty-cycle adjustments such as smooth LED dimming and DC motor velocity profiling.
Versatile Voltage and Power Grid: Supports an output load operating voltage range from 6V up to 40V DC, managing continuous running currents of up to 5 Amps under standard operating conditions.
Low-Voltage Microcontroller Trigger: Functions flawlessly using low-voltage digital control signals from 3.3V to 12V DC, making it plug-and-play compatible with development boards like Arduino, ESP32, STM32, and Raspberry Pi.
Dual-Terminal Layout Safety: Designed with robust terminal blocks on the load paths alongside a standardized pin header layout on the control side for secure, vibration-resistant integration.
Technical Specifications
Feature | Specification |
Core Switching Transistor | FR120N High-Power MOSFET |
Isolation Chipset | High-Speed Onboard Optocoupler |
Output Load Voltage Range | 6V to 40V DC |
Trigger Logic Input Voltage | 3.3V to 12V DC (Supports standard microcontroller outputs) |
Continuous Operating Current | 5 Amps (At standard ambient temperatures) |
Maximum Peak Load Current | Up to 9.4 Amps (For short burst durations) |
Control Signal Frequency Support | Fully compatible with high-speed digital switching and PWM lines |
Board Dimensions | 34 mm x 17 mm x 12 mm |
Hardware Wiring & Interface Configuration
The module features a highly organized layout that ensures straightforward, error-free system wiring:
1. Control Input Side (3-Pin Header)
VCC: Connects to the logic power supply rail of your microcontroller setup (3.3V to 12V).
GND: Connects to the common ground reference of your control logic rail.
IN (Signal Trigger): Connects directly to the digital I/O or PWM output pin of your microcontroller to drive the internal optocoupler.
2. High-Power Load Side (Screw Terminals)
DC+: Connects to the positive power rail of your external high-power DC battery or bench supply (6V to 40V).
DC-: Negative return path of your external high-power supply.
OUT+: Connects directly to the positive power terminal of your target DC motor, solenoid valve, or LED array.
OUT-: Connects directly to the negative return terminal of your target load device.
Common Applications
Solid-State Relay Retrofitting: Replace failure-prone mechanical relays in automated distribution systems to guarantee continuous operation without downtime.
Precision DC Motor Speed Governors: Adjust the velocity of small DC motors, cooling fans, and miniature conveyor tracks via microcontroller PWM duty cycles.
High-Power LED Dimming: Manage industrial lighting configurations, localized laboratory grow lights, or indicator arrays smoothly without flickering.
Solenoid & Actuator Automation: Cycle pneumatic valves, electronic door locks, and automated irrigation solenoids instantly inside smart agriculture panels.
🛠️ Pro-Engineering Operating Tip: Because this module features full optocoupler isolation, it provides complete electrical separation between the control circuit and the high-voltage load circuit. For applications requiring complete isolation against heavy inductive back-electromotive force, make sure that the ground line of your microcontroller loop is kept completely independent from the negative supply terminal of your high-power load battery.
Package Includes:
1 x MOSFET FR120N Control Module (Optocoupler-Isolated Solid-State Relay)