I dunno. This is supposed to be something about voltage - Wokwi ESP32, STM32, Arduino Simulator

int ledpin=3;
void setup() {
  // put your setup code here, to run once:
pinMode(ledpin, OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
analogWrite(ledpin, 255);
delay(1000);

}