RadioBanter - View Single Post

September 14th 04, 06:02 AM

On 13 Sep 2004 21:21:01 GMT, (JGBOYLES) wrote:

I am simply
using a resistive voltage divider, to get a voltage sample, and squaring it
with an AD633 multiplier.

Hi Gary,

If you are thinking of E²/R, you should note this is division, not
multiplication. As such you will need an inverter ahead of the first
product and then a second multiplier to complete the squaring. Then
you would have a problem of dynamic range (not much).

I would suggest you look into turning the voltage into a log
representation so you could then have a linear power scale. Adding
logs is much simpler form of multiplication too and logs give much
more dynamic range. You may lose out in resolution, but if you are
driving a common 3½ digit converter for readout, you can recover that.

73's
Richard Clark, KB7QHC