Re: What's riding on my 60Hz AC? I want to find out

From: Mike Page (mike_at_SCRUBeclectic-CAPSweb.BLAMEco.SWENuk)
Date: 07/12/04 

Date: Mon, 12 Jul 2004 23:21:27 +0100

Tim Wescott wrote:
> Norm Dresner wrote:
>
>> I want to be able to look at the HF content on my 60 Hz AC main supply
>> -- the first use is because I want to see exactly what frequency a
>> "wireless"
>> intercom is using but I'd also like a general capability for later.
>>
>
> Just a capacitor from the line to a resistor to ground should do. Make
> sure the cap only flows a few mA of 60Hz, and consider looking at
> neutral and power the same way. A cap to a coupling transformer would
> work as well, I think most power line stuff happens around 100kHz right
> now, but BPL and others have suggested much higher frequencies.
>

Polypropylene have excellent transient ratings (look at the class X and
class Y types). I would suggest keeping the 60Hz current below 0.5mA. A
couple of MOVs might help to control the local transient level. 

-- 
Mike Page BEng(Hons) MIEE           www.eclectic-web.co.uk
Quiet! Tony's battling the forces of conservatism, whoever we are.

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