Engineers - who uses the poynting vector at work?

"poynting vector" ?

If you mean vectors, you can't do much in the field of AC power systems without using vectors.

Charles Perry P.E.

Why do you have a "?" after "poynting vector" ?

Check out:

Shouldn't it be capitalized to show proper respect for John Henry Poynting (1852-1914) ?

Best regards, Spehro Pefhany

Nah!

Its one of those things you learn and if you have a 3 digit IQ you say, "That's interesting" and do a few exercises to demonstrate that integrating that vector over a closed space DOES give you the electrical energy consumed inside and then forget about it unless you end up teaching a sophomore physics class.

Dunno, is watt (or volt, amp, ohm, ...) capitalized?

You can use the Poynting vector to calculate the time averger power flowing along a waveguide or T-line from the field solutions. Pertubatively, you can caluclate the conduction losses from this.

Of course, the computer would probably do this, but its nice to know.

Gotta love the Poynting vector!

Pratik

If we were referring to a unit called the poynting you'd have a point. It's Ohm's law, Ampère's theorem, and Cooper's droop.

Best regards, Spehro Pefhany

sorry - how quickly we forget....

Should I perhaps add a: ;-)

in article bla8dt$9oldj$ snipped-for-privacy@ID-103962.news.uni-berlin.de, Charles Perry at snipped-for-privacy@hotmail.com wrote on 9/29/03 2:32 PM:

Now I am confused. Charles, I presume that in more modern terminology you mean phasors (complex numbers) rather than vectors. True, phasors do act like two dimensional vectors under addition and subtraction. Dot products may have some meaning in calculating power and the like. But a conceptual stretch is required to put meaning into cross products (vector products that are not true vectors) using phasors.

Getting back to the original question, the Poynting (it derives from a proper name) vector is an extremely usseful concept. When working, it was useful all the time. One should always understand the Poynting theorem which requres integration over a closed surface.

A few years back, in this newsgroup, I had many postings about how the Poynting vector gave me new insight into how transformers worked and how leakage reactance entered into the explanation.

I have been away from this group for a while because my ISP's DSL service was driving me up the wall.

Bill