int ledPin = 9; // LED connected to digital pin 9
int analogPin = A3; // potentiometer connected to analog pin 3
int val = 0; // variable to store the read value

void setup() {
   pinMode(ledPin, OUTPUT); // sets the pin as output file
}

void loop() {
   val = analogRead(analogPin); // read the input pin
   analogWrite(ledPin, (val / 4)); // analogRead values go from 0 to 1023, 
      // analogWrite values from 0 to 255
}