[time-nuts] Re: Another reason to monitor line frequency :) - My AC measurement project & question

[Bob kb8tq]

Hi

None of these transformers are designed for audio use. The same is true
of the various inductors and capacitors mounted up on power poles to try
to phase correct the distribution process. Pretty much all of them are “out 
in the wild” and thus exposed to fairly large temperature swings. 

All of that suggests that the typical power distribution line is pretty narrow 
band / low pass. Indeed back in the day, that’s what we found when measuring 
this and that. 

I’d vote for sticking with the transformer. 

Bob

> On Jan 21, 2022, at 10:16 PM, Keelan Lightfoot <keelanlightfoot at gmail.com> wrote:
> 
> I was pondering this recently. But then I realized something: Sure, something like this would eliminate the transformer… in your house. But there’s still a transformer out on the street somewhere, then another in a substation somewhere, then another in a bigger substation somewhere, then another…
> 
> - Keelan
> 
>> 
>> You can use a capacitorsget your galvanic isolation, and a CR voltage divider with minimal waveform distortion. Pick a burden current (say, 1 mA) and for 120V line, you need 120k impedance at line frequency 60Hz
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