int ledPin = 9;
int ptMeter = A0;
int ptVal;
long ledVal;

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

void loop(){
   ptVal = analogRead(ptMeter);
   ledVal = 0.2490 * ptVal;
   // 255 / 1024

   Serial.println(ledVal);
   analogWrite(ledPin, ledVal);
}