How to Use MOSFETs with Arduino | Drive Loads Safely – Onzuu

If you're working with LEDs, motors, or solenoids and want to control them with an Arduino, using a MOSFET like BSS138 is a reliable and safe way to drive higher current loads. In this guide, you'll learn how to wire, code, and safely operate a MOSFET with your Arduino project.

📌 What Is a MOSFET?

A MOSFET (Metal–Oxide–Semiconductor Field-Effect Transistor) is a switching device used to amplify or switch electronic signals. N-Channel MOSFETs like the BSS138 are commonly used for switching low-side loads.

🔌 Basic Circuit Diagram

This diagram shows a simple circuit where an N-channel MOSFET switches a 12V LED strip using a 5V signal from an Arduino.

💡 Arduino Code Example

int mosfetPin = 9;

void setup() {
  pinMode(mosfetPin, OUTPUT);
}

void loop() {
  analogWrite(mosfetPin, 128); // 50% brightness
  delay(1000);
  analogWrite(mosfetPin, 0);   // off
  delay(1000);
}
  

⚙️ Choosing the Right MOSFET

• Logic-level gate: Ensure it turns on fully with 3.3V or 5V
• Low R_DS(on): For efficient switching
• V_GS(th): Threshold voltage must be lower than your microcontroller's output

📽 Video Guide

📚 Related Guides

• Explore More N-Channel MOSFETs
• ON Semiconductor BSS138