int pname = A3;
float readvalue;
float V2 = 0 ;
int led = 8;
int timedelay = 350;

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

}

void loop() {
  readvalue = analogRead(pname);
  V2 = (5./1023.)*readvalue;
  Serial.print("The potentiometer is set for the voltage : ");
  Serial.print(V2);
  Serial.println(" .");
  if(V2 == 5){
    digitalWrite(led, HIGH);
  }
  else{
    digitalWrite(led, LOW);
  }
  delay(timedelay);

  // put your main code here, to run repeatedly:

}