const int ledPin = 9;       
const int potPin = A0;      
int potValue = 0;           
int ledBrightness = 0;     

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

void loop() {
  potValue = analogRead(potPin);              
  ledBrightness = map(potValue, 0, 1023, 0, 255); 

  analogWrite(ledPin, ledBrightness);         
  delay(10);                                  
}