Xref: utzoo sci.physics:2747 sci.electronics:1858
Path: utzoo!utgpu!water!watmath!clyde!cbosgd!ucbvax!pasteur!trinity!max
From: max@trinity.uucp (Max Hauser)
Newsgroups: sci.physics,sci.electronics
Subject: Re: Neon/gas discharge Iluminators
Summary: voltages?, efficiencies
Message-ID: <215@pasteur.Berkeley.Edu>
Date: 16 Jan 88 15:26:07 GMT
References: <636@ndmath.UUCP>
Sender: news@pasteur.Berkeley.Edu
Reply-To: max@trinity.UUCP (Max Hauser)
Organization: UC Berkeley
Lines: 30

In article <636@ndmath.UUCP> milo@ndmath.UUCP (Greg Corson) writes:
>I recently read about a computer company using a neon tube (bent in
>a serpentine pattern behind diffusing glass) as a backlight for it's
>portable computer LCD screen.  Their reason was supposedly lower power
>requirements than an Electroluminescent pannel.

>Is this correct?  How difficult would it be to make a power supply that
>would run off 6-12 volts to drive such a neon tube.

Sounds reasonable; glow tubes are efficient, cool, diffuse.

How difficult? Depends on the required voltage, which you need to
find out. A neon tube inches long could require kilovolts, which
would be a pity, since up to a few hundred volts there are
simplified, reasonably-efficient (30%-50%) high-voltage generator
circuits from batteries, using a transistor with an inductive
collector load. If you want to be unreasonably efficient, up to
85% or so, you must use a transformer designed for the purpose,
with a proper drive circuit. Middlebrook (?) at Cal Tech has
refined this to an art, and I believe he has a book out.

Sorry that I can't provide hard details about the tubes themselves;
my experience is with the DC-DC conversion part, which I have
used successfully for small (100v) neon bulbs and xenon flashtubes
(200-300v).

Max Hauser / max@eros.berkeley.edu / ...{!decvax}!ucbvax!eros!max

"For every complex problem, there is a solution that is simple,
neat, and wrong." -- H.L. Mencken (as quoted by Ron Ueberschaer)