[time-nuts] Simple AC mains zero-cross detector

Jim Lux jimlux at earthlink.net
Wed Dec 17 13:15:07 EST 2014

On 12/17/14, 6:46 AM, Chuck Forsberg WA7KGX wrote:
> Seems to me CFLs and other loads switching on and off would affect the
> 60 Hz waveform
> enough to make microsecond measurements meaningless.

folks measure the frequency to tenths of a Hz (albeit not a single cycle)..
0.1 Hz out of 60 Hz is 27 microseconds.

But yes, given the terrible power factor of a lot of consumer loads, I 
suspect you could see a change in the phase of the voltage just due to 
the IR drop in the feeder and distribution, since the I isn't in phase 
with the E.

The 15 year old refrigerator I just got rid of was 200W+ and had a PF of 
0.50-0.60, which is pretty bad.

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