int readVal;
int time=400;
int readPin=A1;
int Gpin=5;
float ledVal;

void setup() {
  // put your setup code here, to run once:
Serial.begin(9600);
pinMode(readPin,INPUT);
pinMode(Gpin,OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
readVal=analogRead(readPin);
ledVal=(255./1023.)*readVal;
analogWrite(Gpin,ledVal);
Serial.print("potentiometer voltage =");
Serial.println(ledVal);
delay(time);
}