[time-nuts] 60 Hz frequency and phase measurement

[Mark Sims]

There are numerous devices out there that do non-contact detection of AC voltage in wiring.  The wire just has to be live and not connected to a load.   Fluke sells a nice one, but I like the GVD-505A from GB instruments because it had a pot to adjust the sensitivity.  It has a power switch on the pot... the Fluke has a pushbutton/LED that can be a pain to tell what mode it is in.   The non-contact power detection feature is being built into a lot of new multimeters.   

I also bought a couple of Chinese Fluke style knockoffs... these are dangerous since they don't always respond to conductors carrying current.   The circuit seems to be a CMOS gate with a probe wire connected to a gate input.  I think there was a biasing circuit / coupling cap on the gate input.  Something like that may work for you...