On Sun, 7 Feb 1999 22:55:52 +0200 Mohamed Elegairy <egairy@iname.com>
writes:
>Hi
>I want to use PIC16F84 to measure power factor witch is (as I know )
>the angle between voltage and current.

It's usually shown as the cosine of that angle converted to percentage,
but of course you can compute that in software.

> I know how to detect voltage angle (zero crossing
>) but
>how to do it for the current should I use current transformer? any
>other
>idea.

For small currents (up to tens of amps) it's probably simplest to amplify
the voltage developed across a small resistor in series with the load.
You can even use a section of wire as the resistor but, since the
resistance of wire changes with temperature, that method doesn't have a
lot of absolute precision.  For larger currents use a current transformer
or linear Hall sensor magnetically coupled to a conductor.


___________________________________________________________________
You don't need to buy Internet access to use free Internet e-mail.
Get completely free e-mail from Juno at http://www.juno.com/getjuno.html
or call Juno at (800) 654-JUNO [654-5866]