> Most wristwatches do not have any temperature compensation. If worn, the > wristwatch is pretty close at the 25°C (the human body is a quite good and > temperature stable oven). The difference only starts to > show when the watch > isn't worn for long periods of time.
That explains my experience with the first microcontroller based clock I built years ago. I used a commercial module with a micro and some accessories including a watch crystal for timing. It's on a window ledge facing west in Australia where the temp varies during the year by 40°C. It was always a bit fast and I spent a lot of time checking my code to make sure I was dividing it by the right amount. I eventually tamed it by programming a short pause at 3:00 am. I'm sure the temp of the watch crystal is very rarely 25°C!! Morris _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
