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From: email@example.com (Eric Y. Chang)
Subject: Re: fluorescent lamp inverter problem
Date: Fri, 3 Jan 2003 05:56:57 +0000 (UTC)
Organization: California Institute of Technology, Pasadena
NNTP-Posting-Date: Fri, 3 Jan 2003 05:56:57 +0000 (UTC)
X-Newsreader: TIN [version 1.2 PL2]
Da Man (firstname.lastname@example.org) wrote:
: Often the base only contains a magnetic ballast, and the starter is part of
: the tube socket, since the starters wear out. 4 pins are usually needed to
: fire up a tube without a high voltage kick.
Hi Jeff. The socket is pretty abbreviated. This lamp is designed only
for use with an electronic ballast which does provide such a kick. I
looked at some app notes, and they usually consist of some smart IC which
does this, in addition to running a PFC boost converter and a small
: > There are just two pins. One going into
: > each end of the tube. They usually do not have a starter.
: There is very likely a perminant starter bult into the plug of that tube if
: it only has 2 pins (usally in between the pins in a little protruding box
: (the starter is simular in size to a NE2 neon indicator bulb)). At least
: every 2 pin tube I saw had one built in. The 4 pin ones had the starter
: built in the base, or had an elecronic ballast instead of an magnetic one.
: Check with a normal tube to be sure. That really does sound like it has a
: starter in it, with the blue flash and then the tube going out. Besides,
: what else would make a blue flash?
That is a great idea. I'll have to dig up a regular tube (with filaments)
Meanwhile, I found an interesting www site which said something about the
folly of using a non-square loop ferrite (such as the ones found in PC
power supplies) in a Royer type fluorescent inverter transformer. The
main point is that these kinds of topologies work best with a square loop
material. Since the author did not have such a core, he improvised by
changing the geometry of a PC power supply core so that the region of
saturation is limited in volume. From the basis of power dissipation,
this has a similar effect to squaring up the hysteresis loop. He goes
on to say that this is even better than using a salvaged TV flyback
transformer core. This does not completely answer my question, but it
does go a long way.
Thanks for all the suggestions.
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