Piddling around with more LEDs

I just built one that is pretty successful, using an LM324, a couple of diodes, two yellow LEDs, and some resistors. Oh, and a cap.

It amplifies the ac fluctuations of the forward voltage of one diode, while keeping the dc component the same, and compares it against the other diode. The second LED is for keeping it lit all the time. I wrapped both LEDs in a piece of yellow paper. It flickers quite nicely, and is affected by airflow. It actually looks quite a bit like a candle if you unfocus your eyes... ;)

One could probably use the Vf of the two LEDs instead of using diodes...

Regards, Bob Monsen

Its not that big. My dad is on the other side of that speed bump and doesn't seem to mind. :)

BTW, he called me from Ohio the other day to wish me a merry Christmas, and to tell me that their dog had to walk across an icy sidewalk for the first time in her life. The description of her legs going every which way would have made a cartoon dog proud!

In case you've forgot who I'm talking about, here is a couple pictures of her:

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There are two kinds of people on this earth:
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The first sign of insanity is denying that you\'re crazy.

On a sunny day (Sat, 27 Dec 2008 22:05:38 -0800) it happened Robert Monsen wrote in :

Thats is nice :-) Somebody run to the patent office.... LOL

We have broken the record low for North Central Florida three times this month. So much for glow-ball warming.

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There are two kinds of people on this earth:
The crazy, and the insane.
The first sign of insanity is denying that you\'re crazy.

Come on Michael. Aren't you reading what the warmingists in this group, like Slowman, are saying? Global warming is why it's so cold. Global warming caused the caps on Mars to grow, lack of sun spots, and the heartbreak of seborrhea and psoriasis.

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Keith

Slowman has the honor of being the first listed in news Proxy.

He and his type send an endless stream of "Glow-ball warming" keyboard diarrhea. :(

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There are two kinds of people on this earth:
The crazy, and the insane.
The first sign of insanity is denying that you\'re crazy.

Circuit Cellar had an article on building such a candle a few years back (I can't find my archive CD). IIRC, it implemented a 1/f noise algorithm in a µC and included a thermistor to detect air currents and modify the flicker characteristics.

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Digi-Key has 8,884 items for discrete LEDs Is there Arsenic in old LEDs? Are they RoHS compliant?

Nearly all red, orange, and yellow LEDs prior to the InGaAlP ones that came out in the mid or maybe early 1990's have arsenic. One older red chemistry, having peak wavelength 690, 697 or 700 nm and wide bandwidth, does not.

Apparently includes:

Lumex SSL-LX20465YD (yellow)

Lumex SSL-LX20465ID (A slightly orangish red - known as "high efficiency red" in the late 1970's and early 1980's).

At least 11 through-hole red Avago LEDs are currently in Digi-Key's online catalog, and have wavelengths and brightnesses typical of GaAlAsP (or whatever it is that Avago calls "AlGaAs"), maybe a few of the dimmer ones have GaAsP instead.

- Don Klipstein ( snipped-for-privacy@misty.com)

In , krw wrote in part:

If the ballast puts line frequency AC through the lamp, then the ends do have 60 Hz flicker component. Electronic ballasts usually produce a small amount of 60 Hz flicker - more if their filter capacitors are insufficient or defective. I normally do not see 60 Hz flicker from fluorescents with electronic ballasts, though I do usually see flicker from monitors set to

60 Hz.

- Don Klipstein ( snipped-for-privacy@misty.com)

wwwWWWWOOOOOoosssssshhhhhh! (even after being given a clue, no less)

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Keith

I can see flicker from just about any fluorescent tube if the lighting is just right (wrong?). It usually doesn't bother me too much but I can see it. 60Hz CRT display flicker makes me physically ill. I cannot have a display in my field of view set to 60Hz or I will get ill.

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Keith

If you don't like them i will take them. May not use them for the original purpose though.

So the tubes only conduct in one direction? They should have a 120 Hz flicker rate.

Electronic ballasts usually produce a small

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There are two kinds of people on this earth:
The crazy, and the insane.
The first sign of insanity is denying that you\'re crazy.

In article , Michael A. Terrell wrote, edited for space to concentrate on freq. of f-lamp flicker:

Most of the length of a fluorescent tube does do the same thing during each half-cycle and flickers at 120 Hz. It's the ends that often have a

60 Hz flicker component. Each end usually produces a different amount of light while being the cathode than it does while being the anode.

- Don Klipstein ( snipped-for-privacy@misty.com)

I, Don Klipstein wrote in small part:

Electronic ballasts usually produce a small

Oops, brain fart - electronic ballasts normally have fullwave rectification and whatever line-frequency-related flicker remains after smoothing by the filter capacitor is 120 Hz.

- Don Klipstein ( snipped-for-privacy@misty.com)

Kris Krieger wrote in news:Xns9B80AEF26EE33meadowmuffin@216.168.3.70:

Oh yeah, forgot to mention they were orange. I put them into frosted mini- holders, then into candleholders or whatever.

The only thing that ever bothered me is having a 72 Hz and a 75 Hz monitor side by side. It also drove everyone that saw them running together nuts.

Earth's

That's weird. I have to set these two monitors to different frequencies (75Hz & 85Hz the only choices above 60Hz) or I get interference bars walking through the displays. Which raises the question, how does one get interference bars on two monitors running from the same display card? Seems to be a stupid design.

CRT's I presume?

Field coil magnetics interfere with each other. BTDT