Apptech wrote:
>> So if you'd like to provide comment on my interface 
>> circuit, have a look:
>> <http://nnytech.net/~martin/Power%20Meter.pdf>
>>     
>
>
>
> Seeing that you've gone to the effort of including TR1 - 
> could it's output be used for voltage sensing, making the 
> whole electronic system 'potentially' low voltage? Phase 
> shift of voltage WRT current waveform is crucial for power 
> measurement so you would need to ensure that the electronics 
> power load preserved this.
>
>
>
>         R
>
>   

I've seen small cheap transformers like this operate at near saturation, 
distorting the waveform. I had thought about including a switching power 
supply but it violates the simplicity rule. I wonder if I could keep 
current usage down and use a linear reg. direct from rectified AC. 
Probably not though - I think I'm going to use an 18F or 30F device 
which will use significant current (several mA perhaps).

Thanks for looking at it.
-
Martin
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