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'[EE] Why?'
2011\04\01@210907 by Herbert Graf

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part 1 1652 bytes content-type:text/plain; charset="utf-8" (decoded base64)

This is a case of something being alot weirder then I thought, and I was
wondering if the list could shed some light on my uneducated eyes.

I bought a couple puck Halogen under-cabinet lights at Ikea. They come
with a little "wall wart" type transformer that says it has an output of
12V, supplying up to 20W.

So, curious as I am, I stuck a DMM on the output to see if it spit out
AC or DC (since it says "electronic transformer" on it).

First off, it doesn't spit anything out when the light is disconnected
or switched off.

Switched on the DMM reads 0 on DC, and 7.7V set to AC.

Confused, I stick my small low end digital scope on it, the waveform is
a complete mess, can't seem to get any sort of clean trigger.

It's cases like these where an analog scope is still VERY useful. I
lugged the monster from the basement and connected it; the attached is
what I got.

For the first image the scope is set to 5us/div and 10V/div.
For the second image the scope is set to 2us/div and 10V/div.

As you can see there's a whole spectrum of "stuff" coming out of this
thing. The base switching freq seems to be around 50Khz, I kinda
expected that given the size of the wall wart, but why the spread
spectrum stuff?

Is this for PFC? Is it to reduce EMI or something like that? Anybody
ever design a switching power supply that outputted something like this?

I want to dim these beasties, my initial thought was that the wart
outputted DC and I could use a simple 555 circuit to dim it, now it
looks like I might have to do things another way.

Thanks for any insight!

TTYL

part 2 42583 bytes content-type:image/jpeg; name="scope1.JPG" (decode)


part 3 27458 bytes content-type:image/jpeg; name="scope2.JPG" (decode)


part 4 181 bytes content-type:text/plain; name="ATT00001.txt"
(decoded base64)

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2011\04\01@212519 by David VanHorn

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> So, curious as I am, I stuck a DMM on the output to see if it spit out
> AC or DC (since it says "electronic transformer" on it).


Is the wall wart suspiciously light for a 20W load?  Sounds like an SMPS to me.
Without a load or output filtering, it would act pretty wierd

2011\04\01@212601 by Bob Blick

face
flavicon
face
On Fri, 01 Apr 2011 21:08 -0400, "Herbert Graf" wrote:

>
> As you can see there's a whole spectrum of "stuff" coming out of this
> thing. The base switching freq seems to be around 50Khz, I kinda
> expected that given the size of the wall wart, but why the spread
> spectrum stuff?
>
> Is this for PFC? Is it to reduce EMI or something like that? Anybody
> ever design a switching power supply that outputted something like this?
>
> I want to dim these beasties, my initial thought was that the wart
> outputted DC and I could use a simple 555 circuit to dim it, now it
> looks like I might have to do things another way.

Hi Herbert,

I'm guessing that the frequency changes 120 times per second. Since the
load is basically resistive, they don't need to do PFC. So the frequency
changes because the circuit is simple.

I wonder how well a simple triac-type lamp dimming circuit would work at
50KHz and ~12 volts? RCA used SCR's at 15KHz in televisions and that
worked well. Losses at 12 volts would be substantial, but not crazy.

Cheerful regards,

Bob

-- http://www.fastmail.fm - Faster than the air-speed velocity of an
                         unladen european swallow

2011\04\01@212756 by Herbert Graf

picon face
On Fri, 2011-04-01 at 19:25 -0600, David VanHorn wrote:
> > So, curious as I am, I stuck a DMM on the output to see if it spit out
> > AC or DC (since it says "electronic transformer" on it).
>
>
> Is the wall wart suspiciously light for a 20W load?  Sounds like an SMPS to me.
> Without a load or output filtering, it would act pretty wierd.

Yes, it's very small and light, for a 20W supply it is most certainly an
SMPS.

BTW, the waveforms are with the light ON. I can post pictures of
waveforms with the switch off if anybody is interested.

TTYL

2011\04\01@234040 by Harold Hallikainen

face
flavicon
face
I've seen these "solid state transformers" before for low voltage
lighting. They are just power oscillators driving a small transformer. A
diode bridge on the input with minimal DC filter capacitor. They seem to
work pretty well off a triac dimmer. I've always wondered how the do on
FCC compliance since that 50kHz is carried down external wiring.

Harold



-- FCC Rules Updated Daily at http://www.hallikainen.com - Advertising
opportunities available

2011\04\02@012621 by Steve Smith

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face
Horrible circuit common to nearly all lighting inverters.
Goes a bit like this:-

Little EMC choke and a small cap
Varistor (if you are lucky)
Rectifier
Bigger cap about 0.22- 0.47
Two transistor inverter with a diac to get it going
Transformer

Lamp

The frequency is a bit voltage dependant and because there is a very small
DC bulk cap it makes them spread the noise across a band a little. This has
the effect of limiting the EMC noise when measured with a quasi peak
detector.

Still a horrible little thing.
Steve

{Original Message removed}

2011\04\02@072257 by Jens M. Guessregen

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> I'm guessing that the frequency changes 120 times per second. Since the
load
> is basically resistive, they don't need to do PFC. So the frequency
changes
> because the circuit is simple.

The 12V lamps themselves may be only a resistive load, but the SMPS is a
capacitive load, which requires PFC against the 230V Source.



> I want to dim these beasties, my initial thought was that the wart
outputted DC and I could use a simple 555 circuit to dim it, now it looks
like I might have to do things another way.

@ Herbert, maybe the easiest way is to go back to IKEA (or Obi, Bauhaus,
Praktiker, or your local electric shop) and buy the dimmer, they are
offering for this halogen spots ;-)



Have a nice weekend

Jens

2011\04\02@100525 by Herbert Graf

picon face
On Sat, 2011-04-02 at 06:24 +0100, Steve Smith wrote:
> Horrible circuit common to nearly all lighting inverters.
>
> Goes a bit like this:-
>
> Little EMC choke and a small cap
> Varistor (if you are lucky)
> Rectifier
> Bigger cap about 0.22- 0.47
> Two transistor inverter with a diac to get it going
> Transformer
>
> Lamp
>
> The frequency is a bit voltage dependant and because there is a very small
> DC bulk cap it makes them spread the noise across a band a little. This has
> the effect of limiting the EMC noise when measured with a quasi peak
> detector.
>
> Still a horrible little thing.
Interesting, so what kind of dimmer would work for this sort of thing,
can a cheap triac type dimmer be used safely?

Thanks, TTYL

2011\04\02@170241 by Herbert Graf

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On Sat, 2011-04-02 at 13:22 +0200, Jens M. Guessregen wrote:
> @ Herbert, maybe the easiest way is to go back to IKEA (or Obi, Bauhaus,
> Praktiker, or your local electric shop) and buy the dimmer, they are
> offering for this halogen spots ;-)

Well they do offer "magnetic transformer" dimmers and "electronic
transformer" dimmers, but there are 2 problems:

1) They are PRICEY, $40/each (I'll need at a minimum 3 of them).
2) They are not available as in-line pluggable, which is an issue since
I really don't want to tear the wall apart to do what needs to be done
according to code for a wall box mounted line dimmer.

I might just try a cheap triac based in-line dimmer to see what happens,
worst case I'm out the $13.

As an aside: how do the "magnetic transformer" and "electronic
transformer" dimmers work?

TTYL

2011\04\02@170244 by Herbert Graf

picon face
On Fri, 2011-04-01 at 20:40 -0700, Harold Hallikainen wrote:
> I've seen these "solid state transformers" before for low voltage
> lighting. They are just power oscillators driving a small transformer. A
> diode bridge on the input with minimal DC filter capacitor. They seem to
> work pretty well off a triac dimmer. I've always wondered how the do on
> FCC compliance since that 50kHz is carried down external wiring.

Really? Well that's good, I might go ahead and give it a try then.

Thanks!

2011\04\04@085931 by Gerhard Fiedler

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Herbert Graf wrote:

> 2) They are not available as in-line pluggable, which is an issue
> since I really don't want to tear the wall apart to do what needs to
> be done according to code for a wall box mounted line dimmer.

What is the legal difference between a "home-made wall installation" and
a home-made in-line device plugged into an outlet that's according to
code?

Gerhar

2011\04\04@094225 by RussellMc

face picon face
> What is the legal difference between a "home-made wall installation" and
> a home-made in-line device plugged into an outlet that's according to
> code?

There I know not but, fwiw, here it's substantial. The former may be
illegal and the latter almost uncontrolled,. depending on detail.


       Russel

2011\04\04@102850 by Herbert Graf

picon face
On Sat, 2011-04-02 at 06:24 +0100, Steve Smith wrote:
> Horrible circuit common to nearly all lighting inverters.
>
> Goes a bit like this:-
>
> Little EMC choke and a small cap
> Varistor (if you are lucky)
> Rectifier
> Bigger cap about 0.22- 0.47
> Two transistor inverter with a diac to get it going
> Transformer
>
> Lamp
>
> The frequency is a bit voltage dependant and because there is a very small
> DC bulk cap it makes them spread the noise across a band a little. This has
> the effect of limiting the EMC noise when measured with a quasi peak
> detector.
>
> Still a horrible little thing.
Based on the recommendation from a few here I tried a "normal" triac
based dimmer. No go. The lights were dimmed, but there was a very
audible buzzing sound all the time, and full brightness with the dimmer
was nowhere near full brightness without, so back to square one there.

Anybody know what's in the "electronic transformer" dimmers that lets
them work with these beasties?

Thanks, TTYL

2011\04\04@103630 by Herbert Graf

picon face
On Mon, 2011-04-04 at 09:59 -0300, Gerhard Fiedler wrote:
> Herbert Graf wrote:
>
> > 2) They are not available as in-line pluggable, which is an issue
> > since I really don't want to tear the wall apart to do what needs to
> > be done according to code for a wall box mounted line dimmer.
>
> What is the legal difference between a "home-made wall installation" and
> a home-made in-line device plugged into an outlet that's according to
> code?

Short answer? Alot

Long answer? Anything "mounted" on the wall is considered permanent. As
such, you have to follow very strict rules as to what's permitted and
what isn't. I'm no expert, and I'm leaving certain things out, but
here's the gist:

If you mount the box in the wall then all you really need to do is
install all the wiring (which has to be of a certain type) behind the
wall (within certain guidelines, things like how far back from the wall
does the wire pass through the studs, using nailing plates, etc.). This
obviously requires alot of holes in the walls, and patching afterwards.
It's made even worse so since the wall in question is an exterior wall
mean it's full of insulation and has a vapour barrier which makes using
a fish tape much harder.

If you mount the box ON the wall, then you can't just use regular wire,
it has to be armoured cable or conduit, both very ugly, which is why the
only place you usually see that is outdoors (for conduit) or in
mechanical rooms (i.e. the furnace).

Having a plug in solution is considered "temporary", which is MUCH more
lax in the rules.

This of course all depends on where you are located in the world. What
I've stated is more specific to North America. I have done some
electrical in your neck of the woods and while there are some
differences (mostly related to how different residential building is
done there) the rules are pretty similar (conduit for surface mount
installations is common over there, although for aesthetics you guys
will notch out a grove in the wall, use conduit and then plaster over
it, ALOT of work, but without hollow walls pretty much the only option
post construction).

TTYL

TTYL

2011\04\04@112027 by Carl Denk

flavicon
face
In the USA, essentially all electrical installations of line power (at least 120 volts, there is a voltage below that that is specified as an actual number) must meet the local building code with all wire, devices must meet some ASTM, UL rated, etc, standards. The installation which will define clearances, workmanship is also in the building code. The code is generally a small modification of a national building code, so other than some local slight differences, the installation and equipment will be identical nationwide.

A good reason to be in compliance with the local building code, is your fire insurance may not cover losses where there is non-compliance with the building code. Insurance rated are based on a compliant structure. One may be held liable for a non-compliant installation, both civil or criminal. Local building departments can be fussy about what needs an inspection and not. At the moment our township does not have any building inspection. There is a power struggle going on between the county and townships. The county is slow on inspections, and somewhat costly.

Low voltage installations that are below the code stated minimum are not covered, which includes doorbell from the low voltage transformer terminals, TV, audio, etc.

On 4/4/2011 9:41 AM, RussellMc wrote:
>> What is the legal difference between a "home-made wall installation" and
>> a home-made in-line device plugged into an outlet that's according to
>> code?
>>      
> There I know not but, fwiw, here it's substantial. The former may be
> illegal and the latter almost uncontrolled,. depending on detail.
>
>
>          Russell
>

2011\04\04@112456 by Gerhard Fiedler

picon face
Herbert Graf wrote:

> Having a plug in solution is considered "temporary", which is MUCH
> more lax in the rules.

That's what I figured. It doesn't make much sense to me, though. When it
burns, it burns... and plugged-in devices can run unattended just as
well.


> This of course all depends on where you are located in the world. What
> I've stated is more specific to North America. I have done some
> electrical in your neck of the woods ...

Recently there have been some comments about my "neck of the woods".
There seems to be a confusion about what this is. Not that it matters
much, in general, what people think what it is, but here I'd like to
know what country you're talking about :)

Thanks,
Gerhar

2011\04\04@115718 by Olin Lathrop

face picon face
Gerhard Fiedler wrote:
> Recently there have been some comments about my "neck of the woods".
> There seems to be a confusion about what this is. Not that it matters
> much, in general, what people think what it is, but here I'd like to
> know what country you're talking about :)

I thought you were in Argentina, no?


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2011\04\04@202223 by Gerhard Fiedler

picon face
Olin Lathrop wrote:

> Gerhard Fiedler wrote:
>> Recently there have been some comments about my "neck of the woods".
>> There seems to be a confusion about what this is. Not that it matters
>> much, in general, what people think what it is, but here I'd like to
>> know what country you're talking about :)
>
> I thought you were in Argentina, no?

No. Brazil it is, but I've received some pretty ugly stuff (offlist)
that seemed to imply still something else.

Still I don't know what Herbert was writing about :)

Gerhar

2011\04\04@224000 by Herbert Graf

picon face
On Mon, 2011-04-04 at 21:22 -0300, Gerhard Fiedler wrote:
> Olin Lathrop wrote:
>
> > Gerhard Fiedler wrote:
> >> Recently there have been some comments about my "neck of the woods".
> >> There seems to be a confusion about what this is. Not that it matters
> >> much, in general, what people think what it is, but here I'd like to
> >> know what country you're talking about :)
> >
> > I thought you were in Argentina, no?
>
> No. Brazil it is, but I've received some pretty ugly stuff (offlist)
> that seemed to imply still something else.
>
> Still I don't know what Herbert was writing about :)

For some reason I had in my mind you were in mainland Europe, I must
have confused you with someone else.

Sorry about that.

How is electrical stuff done in Brazil? Is it more like NA or more like
Europe (or something entirely different?))00000000000000.

TTYL

2011\04\05@074928 by Olin Lathrop

face picon face
Herbert Graf wrote:
> For some reason I had in my mind you were in mainland Europe, I must
> have confused you with someone else.

I thought Gerhard grew up in Germany, or at least he is fluent in german.
>From the name I am also guessing his ethnic background is jewish, but that
is purely a (quite possibly wrong) guess on my part.


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(978) 742-9014.  Gold level PIC consultants since 2000

2011\04\05@093658 by Gerhard Fiedler

picon face
Olin Lathrop wrote:

> Herbert Graf wrote:
>> For some reason I had in my mind you were in mainland Europe, I must
>> have confused you with someone else.
>
> I thought Gerhard grew up in Germany, or at least he is fluent in german.

Both correct.

> From the name I am also guessing his ethnic background is jewish, but
> that is purely a (quite possibly wrong) guess on my part.

Fiddler on the roof, hm? :)  No Jewish ancestors, at least not that I
know of.

Gerhar

2011\04\05@095709 by Gerhard Fiedler

picon face
Herbert Graf wrote:

{Quote hidden}

No problem at all. Differently to what some seem to think, it is
possible to consider several countries "one's country" :)

> How is electrical stuff done in Brazil? Is it more like NA or more
> like Europe (or something entirely different?))

Brazil has a mixture of own techniques with influences mainly from
Europe and the USA. I think the European influences are the older ones
and are mainly because of immigration, whereas the US influences seem to
be more recent and mainly because of commerce and business
relationships.
Construction is mainly brick, so burying conduits in brick walls (like
you were talking about) is similar to Europe. The switches that go into
the wall are more similar to the US in style, but recently they forced a
standardization on their own type of outlets. (But the boxes that go
into the wall still are and will remain to be 2"x4" and 4"x4".) Voltages
are regionally different and all over the place (here it's 127V phase to
center, 220V phase to phase), and supply is usually (European-style)
3-phase, with smaller houses only getting one or two of them. Adherence
to code is quite poor, and there's almost no enforcement. It now starts
to be common in new houses to have ground in most or even all outlets,
but that's a very recent development. You still get appliances like
fridges and microwaves with a two-prong plug and a separate ground wire
(which usually isn't connected to anything -- most people don't even
notice it :). Like in NA, electrical supply is taken to the houses
through wires on poles.

Gerhar

2011\04\05@100507 by Olin Lathrop

face picon face
Gerhard Fiedler wrote:
> Fiddler on the roof, hm? :)  No Jewish ancestors, at least not that I
> know of.

I know a family from germany named Fiedler that is definitely jewish.  I
also remember that being the name of a german character in some movie where
the character was jewish, so I thought it a possibility.  I realize some
names go both ways but some are pretty definative.  For example, "Goldstein"
is german meaning gold stone, but so far I've only run into jews with that
name, no non-jewish germans.  On the flip side I haven't run into a jewish
Krause, but several germans with that name.


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(978) 742-9014.  Gold level PIC consultants since 2000

2011\04\06@092803 by Tamas Rudnai

face picon face
On Tue, Apr 5, 2011 at 3:05 PM, Olin Lathrop <spam_OUTolin_piclistTakeThisOuTspamembedinc.com>wrote:

> Gerhard Fiedler wrote:
> > Fiddler on the roof, hm? :)  No Jewish ancestors, at least not that I
> > know of.
>
> I know a family from germany named Fiedler that is definitely jewish.


Mind you, to be Jewish your mother has to be Jewish, not your father -- so
Gerhard's sentence can be still valid if his name was coming from his
father.

Tama

2011\04\06@095811 by Olin Lathrop

face picon face
Tamas Rudnai wrote:
> Mind you, to be Jewish your mother has to be Jewish, not your father
> -- so Gerhard's sentence can be still valid if his name was coming
> from his father.

Actually he said he had no jewish ancestry that he knows of.  My guess about
"Fiedler" suggesting jewish in this case was just plain wrong.


********************************************************************
Embed Inc, Littleton Massachusetts, http://www.embedinc.com/products
(978) 742-9014.  Gold level PIC consultants since 2000

2011\04\06@103718 by Michael Watterson

face picon face
On 06/04/2011 14:58, Olin Lathrop wrote:
> Tamas Rudnai wrote:
>> >  Mind you, to be Jewish your mother has to be Jewish, not your father
>> >  -- so Gerhard's sentence can be still valid if his name was coming
>> >  from his father.
> Actually he said he had no jewish ancestry that he knows of.  My guess about
> "Fiedler" suggesting jewish in this case was just plain wrong.
>

I only briefly considered that Olin was an  angry Norse god before deciding he is American.

My Great Grandfather was Naturalised American, but decided to come back to Ireland and married very late in life after returning. He looks like his wife's Father.

So I was nearly American. Or possibly would not exist. But the point is that HIS grandfather simply adopted the current Surname. So Unless you have looked, you might not be who you think you are. We do 100% know what our real surname is. But that is only one thread of the family. So how meaningful is a surname?

Never judge by Surname. or 1st Name. Or in case of US President by his 2nd name

2011\04\06@110220 by Olin Lathrop

face picon face
Michael Watterson wrote:
> Never judge by Surname. or 1st Name.

I disagree.  It's not definative, of course, but there is information in it..

For example, you'd probably guess right a good fraction of the time that
Dieter Siegfried Mund was from Germany, Luigi Giovanni Panzini from Italy,
and Ian Patrick O'Leary from Ireland, or at least their ancestries.


********************************************************************
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(978) 742-9014.  Gold level PIC consultants since 2000

2011\04\06@110226 by RussellMc

face picon face
> Never judge by Surname. or 1st Name. Or in case of US President by his
> 2nd name.

I dunno. Milhouse sounds pretty convincing.


2011\04\06@110525 by Tamas Rudnai

face picon face
On Wed, Apr 6, 2011 at 3:36 PM, Michael Watterson <.....mikeKILLspamspam@spam@radioway.org> wrote:

> My Great Grandfather was Naturalised American, but decided to come back
> to Ireland and married very late in life after returning. He looks like
> his wife's Father.
>
> So I was nearly American


My grandfather moved from Hungary to Germany where he met his wife, then
they had to move to the Netherlands where my father was born, then they
moved 'back' to Hungary where I was born. Then I moved to the UK, then
Ireland, then UK again (currently I am) -- It is very hard to tell where I
am from, most probably the closest is from 'Europe'.

I guess if the same happens in the US, then you are still US citizen no
matter which state you are moving to or from unlike here in EU.

Tamas



> . Or possibly would not exist. But the point is
> that HIS grandfather simply adopted the current Surname. So Unless you
> have looked, you might not be who you think you are. We do 100% know
> what our real surname is. But that is only one thread of the family. So
> how meaningful is a surname?
>
> Never judge by Surname. or 1st Name. Or in case of US President by his
> 2nd name.
>

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