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'[EE]: [OT]:Phase control dimming on a cheap pic'
2001\03\06@090328 by John

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Hello Roman & PIC.ers,

Our domestic supply here is 240v. 50Hz.
Getting sick of replacing awkward light bulbs, many years ago I fitted
series 1N4007 diodes in some 5 or 6 places around the house.

The result is that these particular bulbs noticeably flicker, but no-one
ever complains about it.
Maybe the inhabitants think their eyes are starting to modulate at 50Hz...
They produce less illumination too, of course, but that is easy
to compensate for by plugging in higher watt-rated units.
The current draw is horribly harmonic (2nd??) and what I'm doing may not
be completely legal either.

BUT, in those years I've never had to replace a single bulb.


best regards,   John

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2001\03\06@092231 by Roman Black

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John wrote:
>
> Hello Roman & PIC.ers,
>
> Our domestic supply here is 240v. 50Hz.
> Getting sick of replacing awkward light bulbs, many years ago I fitted
> series 1N4007 diodes in some 5 or 6 places around the house.
>
> The result is that these particular bulbs noticeably flicker, but no-one
> ever complains about it.
> Maybe the inhabitants think their eyes are starting to modulate at 50Hz...
> They produce less illumination too, of course, but that is easy
> to compensate for by plugging in higher watt-rated units.
> The current draw is horribly harmonic (2nd??) and what I'm doing may not
> be completely legal either.
>
> BUT, in those years I've never had to replace a single bulb.


Cool info John. I can see a few reasons for the
increased bulb life,
* half the average power to the bulb
* half the instances of turn-on surge
* diode may tend to limit turn-on surge current

I wonder how it all adds up. Maybe just using
a large resistor to really limit bulb power
might be good, although much less efficient than
the diode.

I think that NTC varistor + small series
resistor option is looking better.

Here's a thought, maybe putting a decent size
(400v 100uF ?) cap across the bulb would give
less flicker, more light but probably still
keep the advantages re turn on surge?
-Roman

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2001\03\06@094612 by David VanHorn

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>BUT, in those years I've never had to replace a single bulb.

I'm not surprised.
Bulb life is terribly non-linear, and extremely sensitive to voltage.
If you don't mind everything being orange, you can operate it at a low
voltage where the filament evaporation is greatly reduced.

All the diode is doing, is reducing the filament temperature.

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2001\03\06@112057 by Dan Larson

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On Tue, 6 Mar 2001 15:55:17 +0200, John wrote:

>Hello Roman & PIC.ers,
>
>Our domestic supply here is 240v. 50Hz.
>Getting sick of replacing awkward light bulbs, many years ago I fitted
>series 1N4007 diodes in some 5 or 6 places around the house.
>
>The result is that these particular bulbs noticeably flicker, but no-one
>ever complains about it.
>Maybe the inhabitants think their eyes are starting to modulate at 50Hz...
>They produce less illumination too, of course, but that is easy
>to compensate for by plugging in higher watt-rated units.
>The current draw is horribly harmonic (2nd??) and what I'm doing may not
>be completely legal either.

How about using a bridge rectifier so you would get 100Hz flicker and the
current draw would be equal on both halves of the cycle.


>
>BUT, in those years I've never had to replace a single bulb.
>

Well worth the trouble!

Dan


>

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2001\03\06@123950 by Harold M Hallikainen

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       I believe light bulb manufacturers have to balance lamp efficiency
(light output/power input) and lamp life. You can get very long lamp life
by operating at a lower temperature (also changing the color). Probably
the simplest way to do this is to use a lamp rated for a higher voltage.
I've seen some broadcast transmitter sites that are using high wattage
230V lamps at 120V. They're kinda red, aren't very bright, but they last
forever.

Harold


On Tue, 6 Mar 2001 09:46:00 -0500 David VanHorn <dvanhornspamspam_OUTCEDAR.NET>
writes:
{Quote hidden}

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2001\03\06@150530 by Olin Lathrop

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> How about using a bridge rectifier so you would get 100Hz flicker and the
> current draw would be equal on both halves of the cycle.

Then why not remove the diodes altogether and run the bulb directly from the
AC.  The only difference will be that the current reverses on alternate
cycles, but the fillament heating effect will still be the same.  If you
want long bulb life, you can buy a long life bulb, or get a compact
florescent and save energy in the process.


*****************************************************************
Olin Lathrop, embedded systems consultant in Devens Massachusetts
(978) 772-3129, RemoveMEolinTakeThisOuTspamembedinc.com, http://www.embedinc.com

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2001\03\06@172302 by Dale Botkin

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On Tue, 6 Mar 2001, John wrote:

> Hello Roman & PIC.ers,
>
> Our domestic supply here is 240v. 50Hz.
> Getting sick of replacing awkward light bulbs, many years ago I fitted
> series 1N4007 diodes in some 5 or 6 places around the house.
>
> The result is that these particular bulbs noticeably flicker, but no-one
> ever complains about it.
> Maybe the inhabitants think their eyes are starting to modulate at 50Hz...
> They produce less illumination too, of course, but that is easy
> to compensate for by plugging in higher watt-rated units.
> The current draw is horribly harmonic (2nd??) and what I'm doing may not
> be completely legal either.
>
> BUT, in those years I've never had to replace a single bulb.

I remember you usedto be able to buy (maybe still can?) little
button-shaped devices hat would screw into the socket below the base of
the bulb.  These GREATLY extended the life of the bulb, and turn-on was
noticeably, though not objectionaly, slow.  You'd see the lamp go from
soft glow to full brightness in about a second or less.  I think they were
either flat diodes or thermistors.  I was a kid at the time (early 70's)
and haven't seen them in years, so I'm not sure.

Dale
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2001\03\06@210245 by Reginald Neale

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  Dave Van Horn said:

>I'm not surprised.
>Bulb life is terribly non-linear, and extremely sensitive to voltage.

  Lifetime for ordinary tungsten filament lamps is IIRC
  proportional to the twelth power of voltage approximately.
  Thus a change of a little less than 6% in voltage will
  double or halve the life!

  Reg Neale

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2001\03\07@170602 by Peter L. Peres

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>I remember you usedto be able to buy (maybe still can?) little
>button-shaped devices hat would screw into the socket below the base of
>the bulb.  These GREATLY extended the life of the bulb, and turn-on was

They were thermistors usually. The ones advertised as also 'saving energy'
were diodes.

Seriously, any large installation of incandescent bulbs requires these or
sequencing, otherwise you will blow the main fuses at turn-on every time,
or cause a memorable power sag in the building (computers == goodbye).
Think of stadiums and theatres and large halls (restaurants, hotels). I
think that they are mandatory above certain power levels.

Peter

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2001\03\07@235047 by Jinx

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Re: the deterioration of bulb filaments -

http://www.newscientist.com/lastword/lastword.jsp?id=lw1326

Including the "light bulbs don't make light, they suck dark" theory

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2001\03\10@063853 by Jeethu Rao

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"John" <RemoveMEjsandEraseMEspamEraseMEPIXIE.CO.ZA> wrote

> Hello Roman & PIC.ers,
>
> Our domestic supply here is 240v. 50Hz.
> Getting sick of replacing awkward light bulbs, many years ago I fitted
> series 1N4007 diodes in some 5 or 6 places around the house.

Hey, I've been doing this too at my place. But the flicker was real
irritating. Long back I had thought that converting 240volts A.C to D.C and
Chopping it at a high frequency (how about 10 Khz ?  )with a controlled set
of pulses with about 3 out of 8 pulses off. But I never really did it. It
seemed to be too expensive to just increase the life of the light bulb and
to save power.

And who knows, the Thermal and Switching losses may just offset the small
savings.

Regards,

Jeethu Rao

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2001\03\10@122643 by Olin Lathrop

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> Hey, I've been doing this too at my place. But the flicker was real
> irritating. Long back I had thought that converting 240volts A.C to D.C
and
> Chopping it at a high frequency (how about 10 Khz ?  )with a controlled
set
> of pulses with about 3 out of 8 pulses off. But I never really did it. It
> seemed to be too expensive to just increase the life of the light bulb and
> to save power.

You can greatly extend the life of an incandescent bulb by reducing its
voltage, but this is a bad way to "save power".  True, the bulb will draw
less power at a lower voltage, but it will also produce disproportionately
less light, and the perceived light color will be more red.  If you are
willing to tolerate the lower light level, then a lower wattage bulb at its
intended voltage will require less power for the same light output.

Incandescent bulbs are actually very efficient in converting electrical
power into radiation.  Unfortunately, the filament materials avaialable to
us limit the filament temperature, which causes most of the radiation to be
below the visible spectrum.  We are left with a tradeoff between filament
life and efficiency.  At higher temperatures, a greater portion of the black
body radiation is visible, but the filament also gets destroyed more
quickly.


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(978) 772-3129, RemoveMEolinspam_OUTspamKILLspamembedinc.com, http://www.embedinc.com

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2001\03\10@135543 by Sean H. Breheny

face picon face
What about a whole array of windowed JW PICs hooked to the AC supply? ;-)
I've heard tell that they glow very nicely.

Sean

At 12:11 PM 3/10/01 -0500, you wrote:
{Quote hidden}

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2001\03\13@112401 by EDU (1.8d)

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> I believe light bulb manufacturers have to balance lamp efficiency
Unknown command - "I". Try HELP.

> (light output/power input) and lamp life. You can get very long lamp life
Unknown command - "(LIGHT". Try HELP.

> by operating at a lower temperature (also changing the color). Probably
Unknown command - "BY". Try HELP.

> the simplest way to do this is to use a lamp rated for a higher voltage.
Unknown command - "THE". Try HELP.

> I've seen some broadcast transmitter sites that are using high wattage
Unknown command - "I'VE". Try HELP.

> 230V lamps at 120V. They're kinda red, aren't very bright, but they last
Unknown command - "230V". Try HELP.

> forever.
Unknown command - "FOREVER.". Try HELP.

> Harold
Unknown command - "HAROLD". Try HELP.

> On Tue, 6 Mar 2001 09:46:00 -0500 David VanHorn <EraseMEdvanhornspamspamspamBeGoneCEDAR.NET>
Unknown command - "ON". Try HELP.

> writes:
Unknown command - "WRITES:". Try HELP.

All subsequent commands have been flushed.

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