It's just the worst case extremes of a KTY thermistor. 3000 ohm is the max i expect to measure 500 is the minimum. Though still just expectations. But i think that if i use two 8bit registers i will have enough storage space for whatever is measured. ----------------******************************------------------ From: Jinx Is the 500 to 3000 in ohms ? How are you arriving at the numbers ? An internal timing routine ? PWM ? Jinx ______________________________________________________ Get Your Private, Free Email at http://www.hotmail.com