Tom Handley wrote:

>    There has been some discussion on measuring power recently. Analog
> Devices has a specialized A/D converter that's designed for this
> application. It includes two differential A/D channels that feed a
> multiplier with an output converted to frequency. It also includes a
> voltage reference, conditioning circuitry, and runs off a 5V supply.
> The recent flyer quotes a price of $3.20 in 10K volume.
>
>    You measure voltage on one channel and current on the other. The
> output frequency is related to power. I have an application where I'll
> be measuring AC voltage and AC current (using a current transformer) to
> monitor various loads and make decisions on when to `shed' or duty-cycle
> loads. I wish I had this technology back when I was designing energy-
> managemnet systems... For more info:
>
>       Analog Devices Solutions Bulletin, Converters, March 98
>       P/N AD7750
>       www.analog.com/solutions/converters
>       800-262-5643

Time for a South African plug <waving a lighter in the air and listening to
'Nkosi>

SAMES in South Africa make a range of power measurement chips that
can be controller via a serial bus. They are rugged and cheap. The link
for sames is on my page at :

http://www.wasp.co.za/~tjaart/electroniclinks.html

--
Friendly Regards

Tjaart van der Walt
mailto:tjaart@wasp.co.za
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