Message-ID: <002401c4cdc7$94613100$80457ad5@jgtdiynm>
From: "James Moritz" <james.moritz@btopenworld.com>
To: rsgb_lf_group@blacksheep.org
References: <01C4CCB4.3A7963B0.actalbot@southsurf.com>
Date: Thu, 18 Nov 2004 23:37:32 -0000
MIME-Version: 1.0
Subject: Re: LF: Loading Coils
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Dear Andy, LF Group,

----- Original Message -----
From: Andy <actalbot@southsurf.com>
To: <rsgb_lf_group@blacksheep.org>
Sent: Wednesday, November 17, 2004 2:46 PM
Subject: RE: LF: Loading Coils

> > I share my office with some young electronics engineers and was
> > surprised that they know very little about RF inductors or Q factor.
> > It must be a dying art !


> Its not just young electronics engineers who know nothing about inductors.
I
> work with a number of middle aged ones (well, 30 - 50 anyway) who also
know
> next to nothing about inductors, wire antennas, or even radio
communications.

Actually, there is quite a lot of interest in academic and engineering
circles about inductor Q at the moment - but this is about inductors on
ICs - little planar spirals of several nH that occupy quite a lot of space
on most "system on a chip" ICs containing RF transceivers for "Bluetooth",
"WiFi" and so on. A state-of-the-art Q for one of these is about 5 - 10 ...
even with lousy Q like this, circuit designers find they can't live without
them for amplifiers and oscillators and the like, despite spending half a
century inventing circuits to try and get rid of inductors!

> some graduates can't even apply ohms law to a practical
> situation.

As someone who occasionally has to help undergraduates do this, I'm afraid I
have to agree. V = I x R they can usually cope with, but I = V/R is a bit
more challenging, involving division as it does ... any mention of kilohms,
microamps etc. and all bets are off!

Cheers, Jim Moritz
73 de M0BMU