Re: Input power measurement

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Jim Lux by way of Terry Fritz <teslalist-at-qwest-dot-net>" <jimlux-at-earthlink-dot-net>

Even easier with a single chip analog multiplier.  There's a number of
applications notes out from companies like National Semiconductor that
describe watt meters.  Robert Pease (of NatSemi) has written a number of
columns about analog wattmeters of late.

----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Monday, March 17, 2003 7:05 AM
Subject: Re: Input power measurement


 > Original poster: "by way of Terry Fritz <teslalist-at-qwest-dot-net>"
<dhmccauley-at-spacecatlighting-dot-com>
 >
 >
 >  >  > Hi John,
 >  >  >
 >  >  > Yes, to extract the active component of the current means
determining
 >  >  > the portion of the current which is in-phase with the load voltage.
 >  >  >
 >  >  > Thus there's got to be some component which can take in both
signals,
 >  >  > and that component has to somehow effect an instant-by-instant
 >  >  > multiplication of the two waveforms.
 >
 >
 > This can be accomplished through the use of log and anti-log configured
 > op-amps and is fairly easy.
 >
 > The Captain
 >
 >