void setup() {
  pinMode(9, OUTPUT);
  Serial.begin(9600); 

}

void loop() {
  int x = analogRead(A0);
 int PWM = map(x, 0, 1023, 0, 255);   
     Serial.print("PWM: ");      
  Serial.println(PWM);    
delay(100); // 
analogWrite(9,PWM);
}