Wall clock PPM
From Electriki
Jump to navigationJump to searchPPM - A Layman approach to accurate measurements
The wall clock had been running too fast for a long time, about 10min, I wondered how much. Well I could use a stop-watch and count how long it takes to count 60sec. The problem with this is that the uncertainty of my reaction speed would have a significant impact on the result. Say I can react within 1 sec, that is also the resolution on the watch, the potential error is 1/60, or 16667PPM!! (OMG,BBQ,WTF and so on and so forth).
The solution was simple but brilliant (in all modesty).
As a time reference, the clock
