Documentation

Overview

The IRF520 MOSFET Driver Module is the simplest possible power switch: one N-channel MOSFET on a breakout with screw terminals, letting a microcontroller pin switch and PWM loads far beyond what a GPIO could ever source — LED strips, DC motors, fans, pumps, solenoids, and heating elements up to 24 V DC.

Operation is low-side switching: your load’s supply connects to VIN/GND, the load itself sits on the V+/V− output pair, and the MOSFET completes the circuit on the ground side whenever SIG goes high. Because the gate is voltage-controlled, the module draws essentially nothing from your GPIO, and PWM on SIG translates directly into smooth brightness or speed control. An on-board LED shows the switch state.

The one honest caveat: the IRF520 is a classic, not a logic-level MOSFET. It switches fully at a 10 V gate drive; at 5 V logic it handles a few amps, and at 3.3 V it is best kept to roughly an amp. Within that envelope it is a wonderfully robust first power stage. This manual covers the pinout, wiring for Arduino, ESP32, Raspberry Pi, and Pico, PWM code for each, and the questions about heat, inductive loads, and logic levels.

At a Glance

Specifications

Pinout Diagram

Three header pins on the left: SIG (the control/PWM input), VCC (powers the indicator LED), and GND. Two screw-terminal pairs on the right: VIN/GND take the load’s DC supply, and the load itself connects across V+/V−. V+ is joined internally to VIN; V− is the MOSFET-switched return.

Wiring Guide

Code Examples

Arduino — PWM Dimming an LED Strip

const int SIG = 9;

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

void loop() {
  // breathe a 12 V LED strip
  for (int d = 0; d <= 255; d += 3) {
    analogWrite(SIG, d);
    delay(12);
  }
  for (int d = 255; d >= 0; d -= 3) {
    analogWrite(SIG, d);
    delay(12);
  }
}

ESP32 — Fan Speed Steps

const int SIG = 25;

void setup() {
  Serial.begin(115200);
  pinMode(SIG, OUTPUT);
}

void loop() {
  int steps[] = {0, 96, 160, 255};   // off, low, mid, full
  for (int i = 0; i < 4; i++) {
    analogWrite(SIG, steps[i]);
    Serial.printf("Duty: %d/255\n", steps[i]);
    delay(3000);
  }
}

Raspberry Pi — Python (gpiozero)

from gpiozero import PWMOutputDevice
from time import sleep

load = PWMOutputDevice(18, frequency=1000)  # GPIO 18, 1 kHz

try:
    while True:
        for pct in (0.2, 0.5, 0.8, 1.0, 0.0):
            load.value = pct
            print(f"Duty: {pct * 100:.0f}%")
            sleep(2)
except KeyboardInterrupt:
    load.off()

Raspberry Pi Pico — MicroPython

from machine import Pin, PWM
import time

sig = PWM(Pin(15))
sig.freq(1000)

def set_duty(pct):
    sig.duty_u16(int(pct * 65535))

while True:
    # slow ramp up, fast blink, off
    for p in range(0, 101, 2):
        set_duty(p / 100)
        time.sleep(0.05)
    for _ in range(4):
        set_duty(0); time.sleep(0.2)
        set_duty(1); time.sleep(0.2)
    set_duty(0)
    time.sleep(1)

Frequently Asked Questions

Related Tutorials