This sketch reads the value of a potentiometer and controls the brightness of an LED

potentiometer.ino

int potentiometerPin = 0;
int ledPin = 11;
int potentiometerVal = 0;

void setup()
{	
  Serial.begin(9600); // setup serial
}

void loop()
{	
  potentiometerVal = analogRead(potentiometerPin); //I use the map function because PWM pins can only accept
                                                   //values from 0 to 255. Analog pins can output values from
                                                   //0 to 1023. With the map function, the range 0-1023 is

                                                   //converted to appropriate values from 0 to 255.
  
  int mappedVal = map(potentiometerVal,0,1023,0,255);	
  Serial.print(potentiometerVal);
  Serial.print(" - ");
  Serial.println(mappedVal);
  analogWrite(ledPin,mappedVal);
  delay(10);
}