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Today's topics:

* Need help with switching power supply repair - 2 messages, 2 authors
http://groups.google.com/group/sci.electronics.repair/t/efc81d21dede85df?hl=en
* OT Re: CFLs - retrofitting low ESR capacitors - 5 messages, 5 authors
http://groups.google.com/group/sci.electronics.repair/t/4b33f31f667954a0?hl=en
* Rechargable batteries - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/bed135e0d97b3dff?hl=en
* Electromagnetic spectrum – illusion and absurdity - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/d90219824a5fe1f4?hl=en
* wholesale all brand(UGGBOOTS,SHOES,CLOTHES,HANDBAG,WATCH,JEANS,JERSEY,T-
SHIRT,SHIRTS,HOODY,EYEGLASS,CAP,SHAWL,WALLT) and so on. - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/e2b55497fe5b2c3f?hl=en

==============================================================================
TOPIC: Need help with switching power supply repair
http://groups.google.com/group/sci.electronics.repair/t/efc81d21dede85df?hl=en
==============================================================================

== 1 of 2 ==
Date: Sat, Sep 24 2011 5:32 pm
From: "Arfa Daily"

"Geo" <nhhu-o3hu@dea.spamcon.org> wrote in message
news:vp2s77dq27rf3h4is6td7n8mov44rsbqt5@4ax.com...
> On Wed, 21 Sep 2011 13:31:46 -0700 (PDT), senator richards
> <rnewman36@gmail.com> wrote:
>
>>I am trying to troubleshoot a small SMPS that came from an A/V
>>switcher. Input is 120vac and it is supposed to output + and - 15vdc
>>at .8A. Currently it is outputting +17 on one output and somewhere
>>between +22 and +30 on the other output. My experience with SMPS has
>>usually been shorted rectifiers or bad output filter caps so the first
>>thing I did was check all the diodes and replace the output caps.
>>Obviously that didn't fix the problem. The high voltage is about
>>170vdc. The supply to the pwm chip is fluctuating between 7-15v, so
>>i'm thinking this might be the problem, but maybe its something else.
>>In case its not obvious, i'm fairly new to tinkering with these
>>things. Thanks in advance for any help.
>>
> I don't see that a fluctuating supply would cause a polarity reversal
> on the -15v rail.
>

No, you're right, it wouldn't, which is why Franc and I elsewhere in the
thread, have now entered into the discussion of how exactly the OP is taking
his measurements i.e. what point he is using as his ground, for a start.

Arfa

== 2 of 2 ==
Date: Sat, Sep 24 2011 11:00 pm
From: Franc Zabkar

On Sun, 25 Sep 2011 01:29:05 +0100, "Arfa Daily"
<arfa.daily@ntlworld.com> put finger to keyboard and composed:

>Typically, the startup supply doesn't come *directly* from the high voltage
>rail, It is normally fed via a diode, and the self-powering rail is arranged
>to be a higher voltage than the startup supply. This results in the diode
>feeding the startup supply, to become reverse biased once the supply fully
>starts, which then results in the current draw from that supply reducing to
>as good as zero, and thus likewise dropping the power dissipation in the
>startup resistor to virtually zero.
>
>Arfa

Your comment took me by surprise. Just to make sure I wasn't having a
brain fart, I consulted an application note:
http://www.nalanda.nitc.ac.in/industry/AppNotes/Unitrode/slua143.pdf

I confess that I haven't really thought about this subject before, but
according to page 4 of the PDF, there is no back-biased diode. AISI, a
diode that is fed from a 170VDC supply cannot become reverse biased by
a much lower bootstrap voltage.

The app note suggests that the UC3842 will remain in the off state
until the capacitor on its Vcc pin charges up to the UVLO (under
voltage lockout) turn-on voltage of 16V. During this time the IC draws
only 1mA.

After the UVLO turn-on threshold is reached, the IC turns on and
pulses the chopper. The bootstrap winding then generates the Vcc
supply for the IC and prevents the capacitor from discharging below
the IC's UVLO turn-off threshold of 10V.

Fig 31 on page 13 of the same document has an application circuit for
an isolated +/-12V supply. The 56K resistor (R2) can pass about 3mA.
This means that 2mA goes toward charging the capacitor. The UC3842
datasheet specifies a typical operating current of 14mA.

http://www.elektronik.sk/datasheet/UC3842.pdf

If you were to disconnect the bootstrap winding, then the output
voltage will only remain alive for as long as it takes the Vcc
capacitor to discharge from 16V to 10V.

I = C . dV/dt

so ...

dt = C x dV / I

= 100uF x (16V - 10V) / (14 - 3)mA
= 55 msec

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

==============================================================================
TOPIC: OT Re: CFLs - retrofitting low ESR capacitors
http://groups.google.com/group/sci.electronics.repair/t/4b33f31f667954a0?hl=en
==============================================================================

== 1 of 5 ==
Date: Sat, Sep 24 2011 6:52 pm
From: "Arfa Daily"

<snip>

>
> On the other hand, an
>> incandescent bulb uses - what - seven, eight maybe components, each
>> of which could be totally accurately pinned down on their production
>> energy costs. Bear in mind that the processes to produce the
>> components are also very simple and straightforward, unlike the
>> processes required to make the components of a CFL.
>
> **Your point being?
>
> It's not impossible to pin down the cost of manufacturing the relatively
> small number of components in a CFL. Car manufacturers routinely do just
> that, for what is a dramatically more complex device.

But we're not talking cost here. We're talking energy budgets and planetary
pollution from industrial processes. Any fool can say "this transistor costs
us 20 cents. This capacitor costs us 5 cents" and so on. But it's an awful
lot more complex to start looking into the energy budget for refining the
silicon. For turning the silicon into P and N types. For refining the
plastic from the oil. For getting the oil out of the ground. For getting the
iron ore out of the ground. For refining the iron out of the ore, and then
converting it to steel. Transporting all the constituents. Manufacturing
them into a transistor. Then shipping that transistor to the CFL maker. And
on and on. And that's just one component out of a considerable number - see

http://www.pavouk.org/hw/lamp/en_index.html

My point obviously being that in comparison, an incandescent has a very few
constituent parts, all of which are simple, and have simple well defined
manufacturing processes, that could easily be energy budgeted.

>
>>
>>
>>>
>>> Let's put that into some kind of perspective:
>>>
>>> A typical 100 Watt IC lasts for 1,000 hours (at best).
>>> A typical 15 Watt CFL lasts for 5,000 hours (I've certainly
>>> exceeding that figure quite comfortably).
>>
>> I have to say that in my experience, you have been extremely lucky to
>> get that sort of life from CFLs.
>
> **Luck has nothing to do with it. I only buy quality CFLs and I have 19 of
> the suckers in service. If I had (say) 2 in service and not experienced a
> failure, then I might agree with you. I have NINETEEN of them in and
> around my home. And, FWIW: several of them are not installed according to
> manufacturer's instructions. They are surviving nicely.
>
> I have used all sorts over the
>> years, from cheap to expensive, and have never obtained anything like
>> that length of service from any of them, with the exception of some
>> very early ones that I installed in a day nursery that we once owned.
>> They were Dulux globe CFLs and very expensive. We owned that nursery
>> for twelve years, and most of them were still going when we sold it,
>> so I don't dispute that it is possible to make long-lasting CFLs. I
>> just don't think that overall, taken across the whole raft of
>> qualities and costs, they are doing it any more.
>
> **I confess that I have not purchased a CFL for several years, so I can't
> confirm. The damned things are so incredibly long lasting that I simply
> have not had to purchase replacements. In fact, I fully expect LEDs to be
> appropriately priced by the time I need to make any changes.

Well, good luck with that one. As long as they have to keep putting any kind
of control electronics in them to make them run from AC line voltage, then
as long as they are not subsidised, they are never going to get as cheap as
incandescents, or have as low an energy budget to produce. Whilst there have
been some major advances in recent years in the light output and efficiency
of LEDs , they still have relatively poor colour rendition qualities for
home use, and still struggle to produce even omni-directional light as is
required for general lighting, due to the fact that the light is produced at
a flat surface. As to not experiencing the same longevity as you with my
CFLs, I thought that I carefully explained that I have purchased all
qualities of the things, and have not found the expensive 'quality' names to
be any longer lived than the cheapos. This seems to be the findings of
others on here, as well.

<snip>

>> are now gas or nuclear
>
> **Philips cite 6,000 hours for their lamps. Most manufacturers of IC lamps
> cite an average of 750 - 1,000 hours for their standard IC lamps. These
> can be made to last longer, but at the cost of efficiency. Fundamentally,
> however, I take issue with your constant reference to cheap, crappy lamps.
> I have CONSISTENTLY stated that I refer only to quality lamps (like
> Philips). It would be like you trying to argue that automobiles are
> fundamentally unsafe, unreliable and uneconomical, by using ONLY Tata
> automobiles as your reference. You should be using Toyota, Honda, Mecedes,
> Hyundai and the others as part of your reference.
>
> No more talk of cheap, shitty lamps please. Whilst they are are available
> and fools will buy them, they are not representative of state of the art
> in quality or longevity.

Well no. That is an unfair slant in favour of the CFL argument. As long as
cheap crappy ones are available, *most* people - not just "fools" as you so
disparagingly refer to them - will buy them over the expensive quality ones,
because they don't understand the difference, as we do. It's human nature to
buy cheap, which is why the Chinese are doing so well on the back of
world-wide sales of cheap - and often crap quality - electronic goods,
offered for sale through all our nations' supermarkets. This is where the
whole thing breaks down as an argument about the eco validity of any of this
technology. The manufacturers of the cheap CFLs are in it purely to make
money. They have no concern at all for the 'green' credentials of their
products, except in as much as they will sell in their millions,
irrespective of their quality, just because the *are* CFLs. So whilst it is
true what you say in that the cheapo ones are not representative of the
state of the art, unfortunately, they *are* representative of what is being
sold in quantity to the general public, and their contribution to the
validity of the discussion, cannot be ignored until *all* CFLs that are
offered for sale, are indeed representative of the state of the art. I'm
sorry if that offends your sensibilities, but it *is* part of the overall
equation. In fact, your analogy with the cars, is self-defeating, because
you could look at it from the other angle, and say that if you take say BMW
as your reference, then all other cheaper makes are invalid because they are
not 'state of the art', and people who buy them are fools. The cheaper makes
will always be bought by the general public, because not everyone can afford
the safety and performance of a BMW, just like not everyone can afford to
pay £5 or whatever for a bulb to replace an incandescent that they are used
to paying 50 pence for. If there is a CFL costing 50 pence on the shelf
alongside the £5 one, you tell me, which one are most uninformed people
going to buy ? And it is for precisely this reason that the whole CFL thing,
taken on a world-wide basis, falls apart.
>
>>
>>
>>>
>>> And this does not take into pollution created at the point of
>>> manufacture. That is an issue that should be dealt with locally.
>>>
>>>>
>>>> If people want to use CFLs in the belief - mistaken in my opinion -
>>>> that they are in some way helping the world to use less energy, then
>>>> that's fine.
>>>
>>> **It's not a mistaken belief. It's a fact. CFLs use FAR less energy
>>> than incandescents. From cradle to grave. Vastly, hugely less energy.
>>
>>
>> On the face of it, they appear to, and as I said before, that is the
>> *only* angle that's been exploited by the greenies, to try to gain
>> them widespread acceptance.
>
> **Incorrect. ALL green groups have expressed reservations about the proper
> disposal of CFLs.

But that is actually another comparatively minor issue. Important from the
pollution point of view, yes, but insignificant compared to the
manufacturing energy budgets and pollution-causing manufacturing processes,
that are NEVER mentioned by these groups, because they never even consider
these 'hidden' aspects.

>
>
> Personally, I believe that the situation
>> is far less clear than this rather simplistic assumption, when you
>> factor in the *true* costs.
>
> **Fair enough. Cite these "true" costs you speak of. Numbers please.

I cannot give numbers, because there are none that FULLY analyse ALL energy
inputs and pollution outputs for the hundreds of processes involved. And
when I say "costs", I am not talking monetary ones, as I explained earlier.
As I said, I am sure that it is just too complicated a situation to ever be
able to arrive at a real figure, but no matter how much you don't want to
believe it, you have to accept that there *are* many hundreds of process
steps and transport steps involved in CFL manufacture, compared to
incandescent manufacture, which *must* add up to a very significant amount,
that is being totally ignored in making the 'green' case for the things.
Whether it can be accurately quantified or not, if you stop and think about
it, it is common sense.

>
> Almost certainly, they use less energy if
>> you accept the simple picture, get the projected life from them, and
>> believe the equivalence figures for light output, that they put on
>> the boxes. And again, on this score, I understand that they are now
>> trying to legislate over here, to mark the boxes in lumens or some
>> such, probably because users are starting to doubt the quoted
>> equivalence figures. In reality, if you have a genuine like for like
>> in terms of light output, factor in the *real* costs of producing,
>> transporting, and disposing of properly at the end, and get the more
>> typical average service life of 2000 hours from them, then the saving
>> becomes much less significant, and for me, insufficient reason to ban
>> me from using incandescents.
>
> **My CFLs are averaging far more than 2,000 hours. Do you have any data to
> supplort your notion that QUALITY CFLs manage an average of 2,000 hours?
> Are you aware of any consumer legal action against Philips? After Philips
> cite a 6,000 hour life for their product. Here in Australia, the penalties
> are severe for companies engaged in misleading advertising of that nature.
> Recently, LG was penalised several hundred thousand Dollars for making
> misleading claims about the efficiency of their refrigerators. I'm certain
> the legislators would be happy to tackle Philips, if you can supply solid
> supporting evidence to back your claims (about QUALITY CFLs).

See my earlier comments regarding quality CFLs versus the reality of what
people *actually* buy ...

>
>>
>>
>>>
>>> If it's really the case, then CFLs will win out the day
>>>> in the end.
>>>
>>> **By a massive margin, in fact.
>>
>>
>> Distorted by the fact that CFLs are effectively government sponsored,
>
> **Not in Australia. They compete in the market, like any other product.
> They cost approximately 5 times as much as an equivalent IC lamp. They
> last 5 times longer and use 1/5th as much energy.
>
> his might prove an intgeresting read for you:
>
> http://www.choice.com.au/consumer-action/sustainability/energy-efficiency/compact-fluorescent-lightbulbs.aspx
>
>> and that I cannot buy the bulbs I want any more, because they have
>> banned them to make sure that I can't. If it was still incandescents
>> vs CFLs on a level playing field, the take up of CFLs would be much
>> less, which was the reason in the first place that they found it
>> necessary to legislate to force people to use them.
>
> **I agree with that. Most people are, fundamentally, greedy, self-serving,
> fools. They'll choose the cheapest, upfront solution, without regard to
> longevity or running costs.

I don't understand this. By saying that, you make my case for me, and
utterly destroy your own ...

>
>>
>>
>>>
>>> But I think that it is utterly wrong that the existing
>>>> technology has been banned completely on thin evidence and a less
>>>> than truthful declaration of the energy required to make and dispose
>>>> of the things, the only factor being pushed, being the lower energy
>>>> consumption when they are in use, as though this is the be-all and
>>>> end-all of their right to exist, and to be forced on us.
>>>
>>> **Your opinion is duly noted. That comment is a political issue. I
>>> recall EXACTLY the same arguments were made, here in Australia, when
>>> leaded petrol was legislated out of existence. I susepct that, in 20
>>> years, when we look back at this whole discussion, it will appear to
>>> be a non-event. More efficient lighting will be the standard,
>>> incandescents will be relegated to specialised applications (oven
>>> lighting, etc) and the whole issue will be viewed for what it really
>>> is - a storm in a teacup.
>>
>>
>> I fail to see how you equate leaded petrol to the situation with
>> CFLs. It is a different issue entirely, with very clear motives and
>> outcomes. You would have to be brain dead not to understand that
>> putting huge quantities of lead into the atmosphere at ground level
>> and in a form that people could breathe, is bad in every way.
>
> **As is feeding excessive CO2 into the atmosphere. Too much CO2 is causing
> excessive warming of this planet.

That is by no means proven in science. Only in the media. There are many
reputable scientists who believe otherwise.

>
>> Removing lead from petrol had little if any impact on the general
>> public, because it was already possible to build engines that had no
>> requirement for lead in their fuel, without compromising performance.
>
> **That was not the case here in Australia. Manufacturers had to alter
> their production systems, costing millions of Dollars to cope. Most
> automobiles suffered a performance fall when switched to unleaded fuel.
> Those who retained their leaded fuel autos have to use expensive additives
> to compensate.

There is little difference between engines that burn leaded and unleaded
fuel. For sure, there had to be some modification to the production and
design processes, but these occur for the manufacturers every time they
bring out a new model or engine. The monetary costs of doing this are
factored into a new design, so will actually not have been any particularly
burdensome problem for the manufacturers. Drops in performance of existing
engines when converted to run on unleaded fuel were actually fairly minor,
and most people here, at least, did not even bother converting because
leaded petrol was available alongside unleaded, for a reasonable time
period. Back when all this happened, cars were not that long-lived anyway,
so unless you had only just bought a new one, it was no great shakes that
the next one you bought would be produced with an unleaded petrol engine,
already designed in. The manufacturers knew this was coming, and had plenty
of time to carry out the required design alterations, and actually to
amortise the costs in their existing production, in readiness for the
legislation.

>
>
>> It was, unlike CFLs, a classic example of a genuine *replacement*
>> technology, which suffered no disadvantages over the technology that
>> it was replacing.
>
> **Not here in Australia. Costs rose for buyers.
>
> There was not even any need to challenge this bit
>> of legislation, because the advantages were very clear to see in
>> large cities the world over. Even if you clung on to your car that
>> needed leaded petrol, this was still available at the pumps for some
>> years after unleaded came in, and after it was finally removed from
>> sale, there was still LRP (lead replacement petrol) available for
>> some long time after that. Finally, if you still wanted to run your
>> vintage engine, this could be achieved in most cases by the simple
>> expedient of altering the ignition timing, and in the worst case,
>> reducing the compression ratio a little, by fitting a thicker head
>> gasket.
>
> **Incorrect. Leaded fuel vehicles require an additive to allow correct
> operation of valves (seats). The simple expedient of altering timing is
> only for making up for differences in octane, not lead.

The lead was in the petrol as an anti-knock agent, as I recall

>
> CFLs are nothing like this. They are a substitute technology
>> which is unable to replace incandescents in a number of areas - such
>> as decorative light fittings - and having many other shortcomings in
>> comparison to incandescents, in exchange for the dubious possibility
>> that they in some way help to save the planet.
>
> **Specialised IC lamps are still available in Australia. I don't know
> about Europe. Fancy lamps, oven lamps and others are still available. For
> those who refuse to change, halogen replacements are still available.

Nope. Pretty much all outlawed here. You can't get a proper golf ball or
candle any more. You haven't been able to get pearlised bulbs of any
description for a long time. Truly specialised ones for ovens etc are still
available, because it is simply impossible to replace them with anything
else. Halogen 'Apollo nose-cones' are still available at the moment, and
capsule halogens still are, but only in clear envelopes, which are pretty
useless compared to frosted ones. I was looking around the other day to see
if I could still find any halogen replacements (the type where a halogen
capsule bulb is incorporated into a 'traditional' shaped incandescent
envelope), and the only ones of those that I could find were clear. These
give a very harsh light, whereas the pearlised ones, gave a very nice even
light
>
>>

Arfa

== 2 of 5 ==
Date: Sat, Sep 24 2011 7:33 pm
From: TonyS

On 25/09/2011 8:03 AM, Trevor Wilson wrote:
[snipped an awful lot]

> **Perhaps. I swapped out all my iron transformers for SMPS some years ago,
> to increase efficiency. The SMPS seem to deliver a pretty accurate Voltage,
> so I doubt that is an issue. As an aside, my mother has a number of 12 Volt
> halogens in her kitchen. I receive at least 2 calls per year to replace
> blown lamps. I believe that low Voltage halogen downlights are an utterly
> evil blight on society. They are OK for directing light into specific areas,
> but are hopeless at lighting a space, relatively inneficient and they don't
> last very long.

I think there is a place for halogen spot lights. In my kitchen area,
with a pine-lined cathedral ceiling, I have 4 halogens. They are well
placed above the critical spots where I need good lighting.

The 35W lamps from Ikea are just as bright as the old 50W. (Even the 20W
ones could be an option now).

I run them on electronic ballasts and on a trailing edge dimmer, for a
soft background light when the kitchen's closed:)
The dimmer has a soft start switch, very nice!
I have had no 35W lamps failing after 3 years which equates to an
estimated 2000 hrs on full power, and the dimming hasn't done any harm
to them.

I have, for now, substituted 2 of the halogens with LED lights from Deal
Extreme (MR16 4-LED 360-Lumen 3500K Warm White Light Bulb (12V)
Item Number 39027 49.5mm, $8.30) which consume only 6W (6W instead of 35
is a strong argument). They are bright enough but the yellowish colour
really needs to get used to. I don't know if I will keep them or get
some more white ones instead. Maybe someone has tried some more and
different ones? Let us know what you think. There is just too many too
chose from.

Tony

[snipped even more]

== 3 of 5 ==
Date: Sat, Sep 24 2011 9:15 pm
From: Jeff Liebermann

On Sat, 24 Sep 2011 11:02:28 +0100, "Arfa Daily"
<arfa.daily@ntlworld.com> wrote:

>But as I said, coal fired plants have been declining over the years in
>Europe - for instance, we operate just 14 here in the UK now. France has
>none, I believe.

There are about 600 coal plants in the US. The numbers are a bit
misleading as coal fired power plants come in all shapes and sizes.
It's not the number, but the generation capacity that's important. In
the US, we built 10 new plants in 2010 for a total new capacity of
1.6GW (gigawatts). However, if you include decomissioned plants, the
net loss in capacity in 2010 was about -4.6GW lost. Most of the loss
was balanced by a transition to federally subsidized wind power. In
2010, there was also the cancellation of 10 additional plants mostly
due to legislative or EPA restriction. For example, California has a
ban on new coal plants (SB1368). Europe is doing much the same.
<http://www.netl.doe.gov/coal/refshelf/ncp.pdf>
<http://en.wikipedia.org/wiki/Coal_phase_out>
If the EPA gets its way, it's likely that most of the older US coal
plants will need to close to meet emission requirements.
<http://www.sourcewatch.org/index.php?title=Existing_U.S._Coal_Plants>

The loss of -4.6GW of coal generation capacity is not going to make
much of a dent in the mercury emissions. At this time, the US gets
about 45% of about 4 trillion kw-hr of electricity from coal. A few
gigawatts of capacity here and there isn't going to change much.
<http://www.eia.gov/coal/>
Note that capacity loss is usually balanced by burning more coal to
produce more electricity at other plants. Therefore, closing a plant
does NOT constitute an overall decrease in emissions. Only a decrease
in generated mw-hr can decrease emissions.

If you accept my coal generation logic at face value, every product
that uses electricity also dumps mercury into the environment. For
example, my electric water heater would be considered a major
contributor to coal based environmental pollution and far more
significant than a CFL lamp. While this doesn't do anything to help
one decide between CFL and incandescent, it does highlight some
priorities on the process.

>Apparently, the vast majority of increase in CO2 emissions,
>and use of coal to fire power plants, is coming from India and China.

Yep. Something like 90% of the really obnoxious atmospheric pollution
comes from burning coal. There are technologies that drastically
reduce coal fired plant emissions. They're expensive, messy, use huge
amounts of water, and are being largely ignored by the larger plants.
Not so with the smaller plants, a few of which use one or more
technologies.
<http://en.wikipedia.org/wiki/Clean_coal_technology>
As far as I can tell, neither India or China are doing clean coal
plants.

>These
>are both technologically competent nations, who are ignoring any
>responsibility they might have to reduce emissions. So why does that mean
>that I have to suffer a 'pissing into the wind' replacement for technology
>that I am happy with, so they can carry on regardless ?

I don't have an answer to the "why". Most likely, both countries
economies will collapse without the generated power, which makes it
one of many "necessary evils".

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

== 4 of 5 ==
Date: Sat, Sep 24 2011 11:37 pm
From: Mick DaDik

Hi Tony,

> I have, for now, substituted 2 of the halogens with LED lights from Deal
> Extreme (MR16 4-LED 360-Lumen 3500K Warm White Light Bulb (12V)
> Item Number 39027 49.5mm, $8.30) which consume only 6W (6W instead of 35
> is a strong argument). They are bright enough but the yellowish colour
> really needs to get used to. I don't know if I will keep them or get
> some more white ones instead. Maybe someone has tried some more and
> different ones? Let us know what you think. There is just too many too
> chose from.

I have replaced 6 x 50w Halgens in our kitchen with 6 x these ones 3.8w each

http://www.dealextreme.com/p/mr16-3-8w-60-led-6500k-360-lumen-light-bulb-white-12v-30825

and I have to say I am happy on several fronts.

firstly it consumes only 23w compared to 300w of the originals.
secondly they run cool not burning hot
thirdly the light is WHITE not yellow and floods the kitchen rather than
being directional like the halogens were.

Our ceilings are 9ft and the halogens created a bright area that was
very narrow and left deep shadows to the sides of the area...

These LEDs `flood' the whole area and in effect create a daylight
environment much more pleasing to me.

I will add that whilst they ran on AC 12V they had a slight flicker I
found disturbing so I now run them off 12Vdc and they are great.

mick

== 5 of 5 ==
Date: Sun, Sep 25 2011 12:03 am
From: kreed

On Sep 25, 11:52 am, "Arfa Daily" <arfa.da...@ntlworld.com> wrote:
> <snip>
>
>
>
> > On the other hand, an
> >> incandescent bulb uses - what - seven, eight maybe components, each
> >> of which could be totally accurately pinned down on their production
> >> energy costs. Bear in mind that the processes to produce the
> >> components are also very simple and straightforward, unlike the
> >> processes required to make the components of a CFL.
>
> > **Your point being?
>
> > It's not impossible to pin down the cost of manufacturing the relatively
> > small number of components in a CFL. Car manufacturers routinely do just
> > that, for what is a dramatically more complex device.
>
> But we're not talking cost here. We're talking energy budgets and planetary
> pollution from industrial processes. Any fool can say "this transistor costs
> us 20 cents. This capacitor costs us 5 cents" and so on. But it's an awful
> lot more complex to start looking into the energy budget for refining the
> silicon. For turning the silicon into P and N types. For refining the
> plastic from the oil. For getting the oil out of the ground. For getting the
> iron ore out of the ground. For refining the iron out of the ore, and then
> converting it to steel. Transporting all the constituents. Manufacturing
> them into a transistor. Then shipping that transistor to the CFL maker. And
> on and on. And that's just one component out of a considerable number - see
>
> http://www.pavouk.org/hw/lamp/en_index.html
>
> My point obviously being that in comparison, an incandescent has a very few
> constituent parts, all of which are simple, and have simple well defined
> manufacturing processes, that could easily be energy budgeted.
>
>
>
>
>
> >>> Let's put that into some kind of perspective:
>
> >>> A typical 100 Watt IC lasts for 1,000 hours (at best).
> >>> A typical 15 Watt CFL lasts for 5,000 hours (I've certainly
> >>> exceeding that figure quite comfortably).
>
> >> I have to say that in my experience, you have been extremely lucky to
> >> get that sort of life from CFLs.
>
> > **Luck has nothing to do with it. I only buy quality CFLs and I have 19 of
> > the suckers in service. If I had (say) 2 in service and not experienced a
> > failure, then I might agree with you. I have NINETEEN of them in and
> > around my home. And, FWIW: several of them are not installed according to
> > manufacturer's instructions. They are surviving nicely.
>
> > I have used all sorts over the
> >> years, from cheap to expensive, and have never obtained anything like
> >> that length of service from any of them, with the exception of some
> >> very early ones that I installed in a day nursery that we once owned.
> >> They were Dulux globe CFLs and very expensive. We owned that nursery
> >> for twelve years, and most of them were still going when we sold it,
> >> so I don't dispute that it is possible to make long-lasting CFLs. I
> >> just don't think that overall, taken across the whole raft of
> >> qualities and costs, they are doing it any more.
>
> > **I confess that I have not purchased a CFL for several years, so I can't
> > confirm. The damned things are so incredibly long lasting that I simply
> > have not had to purchase replacements. In fact, I fully expect LEDs to be
> > appropriately priced by the time I need to make any changes.
>
> Well, good luck with that one. As long as they have to keep putting any kind
> of control electronics in them to make them run from AC line voltage, then
> as long as they are not subsidised, they are never going to get as cheap as
> incandescents, or have as low an energy budget to produce. Whilst there have
> been some major advances in recent years in the light output and efficiency
> of LEDs , they still have relatively poor colour rendition qualities for
> home use, and still struggle to produce even omni-directional light as is
> required for general lighting, due to the fact that the light is produced at
> a flat surface. As to not experiencing the same longevity as you with my
> CFLs, I thought that I carefully explained that I have purchased all
> qualities of the things, and have not found the expensive 'quality' names to
> be any longer lived than the cheapos. This seems to be the findings of
> others on here, as well.
>
> <snip>
>
> >> are now gas or nuclear
>
> > **Philips cite 6,000 hours for their lamps. Most manufacturers of IC lamps
> > cite an average of 750 - 1,000 hours for their standard IC lamps. These
> > can be made to last longer, but at the cost of efficiency. Fundamentally,
> > however, I take issue with your constant reference to cheap, crappy lamps.
> > I have CONSISTENTLY stated that I refer only to quality lamps (like
> > Philips). It would be like you trying to argue that automobiles are
> > fundamentally unsafe, unreliable and uneconomical, by using ONLY Tata
> > automobiles as your reference. You should be using Toyota, Honda, Mecedes,
> > Hyundai and the others as part of your reference.
>
> > No more talk of cheap, shitty lamps please. Whilst they are are available
> > and fools will buy them, they are not representative of state of the art
> > in quality or longevity.
>
> Well no. That is an unfair slant in favour of the CFL argument. As long as
> cheap crappy ones are available, *most* people - not just "fools" as you so
> disparagingly refer to them - will buy them over the expensive quality ones,
> because they don't understand the difference, as we do. It's human nature to
> buy cheap, which is why the Chinese are doing so well on the back of
> world-wide sales of cheap - and often crap quality - electronic goods,
> offered for sale through all our nations' supermarkets. This is where the
> whole thing breaks down as an argument about the eco validity of any of this
> technology. The manufacturers of the cheap CFLs are in it purely to make
> money. They have no concern at all for the 'green' credentials of their
> products, except in as much as they will sell in their millions,
> irrespective of their quality, just because the *are* CFLs. So whilst it is
> true what you say in that the cheapo ones are not representative of the
> state of the art, unfortunately, they *are* representative of what is being
> sold in quantity to the general public, and their contribution to the
> validity of the discussion, cannot be ignored until *all* CFLs that are
> offered for sale, are indeed representative of the state of the art. I'm
> sorry if that offends your sensibilities, but it *is* part of the overall
> equation. In fact, your analogy with the cars, is self-defeating, because
> you could look at it from the other angle, and say that if you take say BMW
> as your reference, then all other cheaper makes are invalid because they are
> not 'state of the art', and people who buy them are fools. The cheaper makes
> will always be bought by the general public, because not everyone can afford
> the safety and performance of a BMW, just like not everyone can afford to
> pay £5 or whatever for a bulb to replace an incandescent that they are used
> to paying 50 pence for. If there is a CFL costing 50 pence on the shelf
> alongside the £5 one, you tell me, which one are most uninformed people
> going to buy ? And it is for precisely this reason that the whole CFL thing,
> taken on a world-wide basis, falls apart.
>
>
>
>
>
> >>> And this does not take into pollution created at the point of
> >>> manufacture. That is an issue that should be dealt with locally.
>
> >>>> If people want to use CFLs in the belief - mistaken in my opinion -
> >>>> that they are in some way helping the world to use less energy, then
> >>>> that's fine.
>
> >>> **It's not a mistaken belief. It's a fact. CFLs use FAR less energy
> >>> than incandescents. From cradle to grave. Vastly, hugely less energy.
>
> >> On the face of it, they appear to, and as I said before, that is the
> >> *only* angle that's been exploited by the greenies, to try to gain
> >> them widespread acceptance.
>
> > **Incorrect. ALL green groups have expressed reservations about the proper
> > disposal of CFLs.
>
> But that is actually another comparatively minor issue. Important from the
> pollution point of view, yes, but insignificant compared to the
> manufacturing energy budgets and pollution-causing manufacturing processes,
> that are NEVER mentioned by these groups, because they never even consider
> these 'hidden' aspects.
>
>
>
> > Personally, I believe that the situation
> >> is far less clear than this rather simplistic assumption, when you
> >> factor in the *true* costs.
>
> > **Fair enough. Cite these "true" costs you speak of. Numbers please.
>
> I cannot give numbers, because there are none that FULLY analyse ALL energy
> inputs and pollution outputs for the hundreds of processes involved. And
> when I say "costs", I am not talking monetary ones, as I explained earlier.
> As I said, I am sure that it is just too complicated a situation to ever be
> able to arrive at a real figure, but no matter how much you don't want to
> believe it, you have to accept that there *are* many hundreds of process
> steps and transport steps involved in CFL manufacture, compared to
> incandescent manufacture, which *must* add up to a very significant amount,
> that is being totally ignored in making the 'green' case for the things.
> Whether it can be accurately quantified or not, if you stop and think about
> it, it is common sense.
>
>
>
> > Almost certainly, they use less energy if
> >> you accept the simple picture, get the projected life from them, and
> >> believe the equivalence figures for light output, that they put on
> >> the boxes. And again, on this score, I understand that they are now
> >> trying to legislate over here, to mark the boxes in lumens or some
> >> such, probably because users are starting to doubt the quoted
> >> equivalence figures. In reality, if you have a genuine like for like
> >> in terms of light output, factor in the *real* costs of producing,
> >> transporting, and disposing of properly
>
> ...
>
> read more »

As for cheap CFL, we used to buy those 4 packs for about $7.50 from
Bunnings. probably 1 out of 10 would fail after a few months, but the
others have gone for about 3 years so far (50 bought all up). I also
noticed that since the light bulbs have been banned, the cheap CFL's
have all but disappeared and its hard to find any that are under the
$3-4 mark. Most also have this sickening "warm white" light, rather
than the proper "cool white" or "daylight" that is normal with fluros.

I still have some GE CFL ones I bought about 2002 that are working.
Most though last nowhere near as long as incandescents though and they
do not like a lot of the light fittings used in typical Australian
homes.
They either face down, or don't have enough ventilation, or simply
don't fit in them

The one advantage they have over incandescents is that they are not
affected by vibration.

==============================================================================
TOPIC: Rechargable batteries
http://groups.google.com/group/sci.electronics.repair/t/bed135e0d97b3dff?hl=en
==============================================================================

== 1 of 1 ==
Date: Sat, Sep 24 2011 7:57 pm
From: "Phil Allison"

"Arfa Daily"

>
> It says that they are NiMH at the the bottom left of the card, and it
> indicates on the battery body that they are 2400mAH,

** Nope.

DX2400 is a code that gives the battery type and size.

Seems they are really Sanyo Eneloop AAA cells in a new skin.

So they are 800 mAH.

AAAs are never 2400mAH.

... Phil

==============================================================================
TOPIC: Electromagnetic spectrum – illusion and absurdity
http://groups.google.com/group/sci.electronics.repair/t/d90219824a5fe1f4?hl=en
==============================================================================

== 1 of 1 ==
Date: Sat, Sep 24 2011 9:52 pm
From: Jeff Liebermann

On Sat, 24 Sep 2011 19:31:34 -0400, Jamie
<jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote:

>Jeff Liebermann wrote:
>> On Sat, 24 Sep 2011 10:32:29 -0400, Jamie
>> <jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote:
>>
>>
>>>It was once absurd to think the world was round.
>>>Jamie
>>
>>
>> The earth is not round. It's an oblate spheroid.
>>
> Like global warming is a lie? Because the sun
>only heats one side at a time?

The ancients believed in a flat earth and didn't have any problems
with global warming. Obviously, the solution to global warming is to
flatten the planet.

> I saw that some where.

Even if you don't believe the earth is an oblate spheroid, it's also
not "round". Just "round" is ambiguous and might imply a disk, as in
a flat earth. I suggest you use the term "sphere" instead of "round".

>Jamie

The problem with the original article is that the author fails to
understand how a cavity magnetron operates. It's basically a whistle
operating at microwave frequencies. The physics of a whistle are not
trivial. The electron beam entering the cavity crosses the beam
exiting the cavity. The transition is unstable, causing the beam to
oscillate at a rate controlled by the circumference of the cavity.
Rather than accept the mechanical analogy, the author presents a
rather bizarre and faulty explanation, and then concludes that it must
be the result of some new and previously unknown principle. Methinks
not.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

==============================================================================
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SHIRT,SHIRTS,HOODY,EYEGLASS,CAP,SHAWL,WALLT) and so on.
http://groups.google.com/group/sci.electronics.repair/t/e2b55497fe5b2c3f?hl=en
==============================================================================

== 1 of 1 ==
Date: Sun, Sep 25 2011 12:06 am
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