I bought a cheap flourescent luminair. Works of 12 VDC 500mA.

I took it apart because I thought the lamp inside is about the right size
for a project. Ballast is electronic on a small PCB, only a few descrete
components. Obviously the ballast is cheap to make.

Inside is an unbranded T5 lamp of 8W. It's 288mm long so it is a mini TL
lamp. Two pins on each end.

Looking at Philips technical site I see that the recommended ballast for
this kind of Philips lamp/lamp would be type BPL 02W. This ballast is a
simple inductor. It's compactish, 85mm x 39mm x 28mm. Wiring is standard
when using a choke and a starter.

But, the electronic ballast in this luminaire does not employ the heaters.
Pins at both end are joined together.

I suppose that whether employing the cheap electronic ballast or the
choke,
the lamp gives the same light output. True? But for economy, I guess one
would always go with the proprietry electronic ballast. Although mains
working would require a step doen transformer. So, cost savings would
not materilise - perhaps.

Not sure about any differences in lamp protection and safety.

I just get to wondering when I come across this kind of thing why anyone
would select the choke ballast.

I bought a cheap fluorescent luminair. Works of 12 VDC 500mA.

I took it apart because I thought the lamp inside is about the right size
for a project. Ballast is electronic on a small PCB, only a few descrete
components. Obviously the ballast is cheap to make.

Inside is an unbranded T5 lamp of 8W. It's 288mm long so it is a mini TL
lamp. Two pins on each end.

Looking at Philips technical site I see that the recommended ballast for
this kind of Philips lamp/lamp would be type BPL 02W. This ballast is a
simple inductor. It's compactish, 85mm x 39mm x 28mm. Wiring is standard
when using a choke and a starter.

But, the electronic ballast in this luminaire does not employ the heaters.
Pins at both end are joined together.

I suppose that whether employing the cheap electronic ballast or the
choke,
the lamp gives the same light output. True? But for economy, I guess one
would always go with the proprietry electronic ballast. Although mains
working would require a step doen transformer. So, cost savings would
not materilise - perhaps.

Not sure about any differences in lamp protection and safety.

I just get to wondering when I come across this kind of thing why anyone
would select the choke ballast.

I bought a cheap flourescent luminair. Works of 12 VDC 500mA.

I took it apart because I thought the lamp inside is about the right size
for a project. Ballast is electronic on a small PCB, only a few descrete
components. Obviously the ballast is cheap to make.

Inside is an unbranded T5 lamp of 8W. It's 288mm long so it is a mini TL
lamp. Two pins on each end.

Looking at Philips technical site I see that the recommended ballast for
this kind of Philips lamp/lamp would be type BPL 02W. This ballast is a
simple inductor. It's compactish, 85mm x 39mm x 28mm. Wiring is standard
when using a choke and a starter.

But, the electronic ballast in this luminaire does not employ the heaters.
Pins at both end are joined together.

I suppose that whether employing the cheap electronic ballast or the choke,
the lamp gives the same light output. True? But for economy, I guess one

would always go with the proprietry electronic ballast. Although mains
working would require a step doen transformer. So, cost savings would
not materilise - perhaps.

Not sure about any differences in lamp protection and safety.

I just get to wondering when I come across this kind of thing why anyone
would select the choke ballast.

I bought a cheap flourescent luminair. Works of 12 VDC 500mA.

In article <6f38caF9kj2qU1 at (no spam) mid.individual.net>,
"Richard" <some_email at (no spam) ntlworld.com> writes:
I bought a cheap flourescent luminair. Works of 12 VDC 500mA.

I took it apart because I thought the lamp inside is about the right size
for a project. Ballast is electronic on a small PCB, only a few descrete
components. Obviously the ballast is cheap to make.

Inside is an unbranded T5 lamp of 8W. It's 288mm long so it is a mini TL
lamp. Two pins on each end.

Looking at Philips technical site I see that the recommended ballast for
this kind of Philips lamp/lamp would be type BPL 02W. This ballast is a
simple inductor. It's compactish, 85mm x 39mm x 28mm. Wiring is standard
when using a choke and a starter.

But, the electronic ballast in this luminaire does not employ the
heaters.
Pins at both end are joined together.

Many of those cheap battery inverters don't drive the tube
very well. The lack of preheating will result in fewer starts,
but worse, they often significantly under-run the tube, meaning
the filaments don't get as hot as they should, ant this also
reduces tube live. Often doesn't matter with battery lights as
they aren't operated for that long (battery replacement price
and frequency would become a significant issue).

I suppose that whether employing the cheap electronic ballast or the
choke,
the lamp gives the same light output. True? But for economy, I guess one

As I said, many of those cheap battery inverters significantly
under-run the tube, and get short tube life as a result.

would always go with the proprietry electronic ballast. Although mains
working would require a step doen transformer. So, cost savings would
not materilise - perhaps.

Not sure about any differences in lamp protection and safety.

I just get to wondering when I come across this kind of thing why anyone
would select the choke ballast.

They are cheap. It's also worth pointing out that the 4/6/8W T5
tubes don't work very well on 240V series ballasts with glow
starters. Two things are non-optimal - the 240V mains voltage
can sometimes instant-start them before the filaments get heated up,
but if it doesn't, it can take quite a bit of flashing to get them
started. Glow-start works well with all tubes from 24" upwards
on 240V, but not with the very short tubes.

I would suggest you get a Philips MF-Matchbox 109 ballast. This
is a mains electronic ballast for this tube. It comes in two
types, Blue which is instant start, and Red which is preheat.
Preheat will give longer tube life in the case of frequently
switching on and off. Instant start may be preferable where
you don't want a second or so starting delay and either don't
switch on and off frequently or don't care about the reduction
in tube life. Both types require 4 connections to the tube and
power the filaments (unlike US instant-start circuits). Each
type is available in 2 shapes -- a matchbox, or a longer thinner
box (more suitable for going into a thin T5 fitting), and both
these are also available as just the bare circuit board too.

RS do the Blue cased ones for around £7 (+ VAT/P&P):
http://uk.rs-online.com/web/search/searchBrowseAction.html?method=searchProducts&searchTerm=philips+matchbox

The other thing you might be interested in is making your own
ballast from an old CFL. There are some notes here:

http://www.cucumber.demon.co.uk/lights/diy/

The following shows the Philips matchbox ballast retrofitted
into a light and driving a 10W 2D lamp

http://www.cucumber.demon.co.uk/lights/diy2/

Lets say I'm making a table lamp using a miniature T5, something like an 8W
or 13W lamp.

There are at least two ways:

1 You employ a 12V (say) adaptor, and that plugs into the table lamp. Of
course the simple inverter inside the table lamp is very small and very
cheap.

2 Another way is to feed the lamp directly with AC mains using either
something like a Philips Matchbox ballast, or a simple small choke ballast.

Because I've got in my head the notion that option 2 is the more expensive
option, because of expensive ballasts I'm always thinking that option 1 is
better.

But, I'm not sure option 2 needs to be as expensive as I think it is. I
think this proves the point:

http://www.dealec.co.uk/acatalog/erc_compact_fluorescent_ballasts_mec75.html

I bought a cheap flourescent luminair. Works of 12 VDC 500mA.

I took it apart because I thought the lamp inside is about the right size
for a project. Ballast is electronic on a small PCB, only a few descrete
components. Obviously the ballast is cheap to make.

Inside is an unbranded T5 lamp of 8W. It's 288mm long so it is a mini TL
lamp. Two pins on each end.

Looking at Philips technical site I see that the recommended ballast for
this kind of Philips lamp/lamp would be type BPL 02W. This ballast is a
simple inductor. It's compactish, 85mm x 39mm x 28mm. Wiring is standard
when using a choke and a starter.

But, the electronic ballast in this luminaire does not employ the heaters.
Pins at both end are joined together.

I suppose that whether employing the cheap electronic ballast or the choke,
the lamp gives the same light output. True?

But for economy, I guess one
would always go with the proprietry electronic ballast. Although mains
working would require a step doen transformer.

So, cost savings would
not materilise - perhaps.

Not sure about any differences in lamp protection and safety.

I just get to wondering when I come across this kind of thing why anyone
would select the choke ballast.

On Sun, 27 Jul 2008 13:35:40 +0100, "Richard"
some_email at (no spam) ntlworld.com> wrote:

I bought a cheap flourescent luminair. Works of 12 VDC 500mA.

I took it apart because I thought the lamp inside is about the right size
for a project. Ballast is electronic on a small PCB, only a few descrete
components. Obviously the ballast is cheap to make.

Inside is an unbranded T5 lamp of 8W. It's 288mm long so it is a mini TL
lamp. Two pins on each end.

Looking at Philips technical site I see that the recommended ballast for
this kind of Philips lamp/lamp would be type BPL 02W. This ballast is a
simple inductor. It's compactish, 85mm x 39mm x 28mm. Wiring is standard
when using a choke and a starter.

But, the electronic ballast in this luminaire does not employ the heaters.
Pins at both end are joined together.

Sorry to be a bit late to this discussion.

As others have stated, the electronic ballast operates this
lamp in what we in the US would call instant start mode.

I suppose that whether employing the cheap electronic ballast or the
choke,
the lamp gives the same light output. True?

Not true. Fluorescent lamps give more light output per watt
of power input when operated at frequencies above about
10kHz. If the electronic ballast is of reasonable quality,
then it will give higher overall efficacy than the series
choke system.

But for economy, I guess one
would always go with the proprietry electronic ballast. Although mains
working would require a step doen transformer.

No again. As I think Terry has pointed out, as long as the
mains have enough voltage, the series choke takes care of
the "excess" voltage.

So, cost savings would
not materilise - perhaps.

Not sure about any differences in lamp protection and safety.

I just get to wondering when I come across this kind of thing why anyone
would select the choke ballast.

They were, and may still be, lower cost and that are also
the basic "standard" ballast for this type of lamp.

--
Vic Roberts
http://www.RobertsResearchInc.com