Archive for the ‘LEDs’ Category:

2018-12-04 FETs For Very Low Voltage Joule Thiefs

from FB group Building Transistor Radios 2018 Dec 4 Terry Harris I didn’t try to mimic the ALD, I used the FETs for a voltage booster. The typical 5mm LED needs somewhere around 60 mW for Max brightness. If I was powering it with 60 millivolts, it would require over an amp to get the

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2018-11-10 LEDs Are Not Linear Resistances

from FB group Arduino Projects 2018-11-11 As it is, the 6 ohm resistor has 1 amp going through it. Your LED(s) is dissipating 6.55V times 1 amp or 6.55 watts. The LED is not a linear resistance, the voltage doesn’t go up directly as the current increases. The voltage across the LED will stay at

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2018-07-30 How Are LED Lights Made Dimmable?

From FB comment to Bill Sherman’s candelabra lamps. Bill Sherman Sometimes I wonder what is meant by dimmable. If a LED light uses hundreds of microfarads for the DC filter capacitor, then when the light is dimmed, the long time constant causes it to flash on and off when it is dimmed. So if the

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2018-02-14  LED 2nds, Factory Rejects

I’ve had several LED purchases that were LEDs of poor quality, actually factory rejects.  The sellers may not have known that the LEDs had “chipped chips” missing a piece, or bubbles or inclusions, but even more commonly, the LED chip is off center so the beam pattern is distorted.  I let the sellers know, and

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2016-04-16 Plastic Bag Heat Sealer

I was at Daiso, the dollar and a half store where everything is labeled in Japanese.  I saw a little gizmo that looks like it runs off batteries, and heats up a fine wire to melt and seal plastic bags. I got to thinking about it after I left without one.  A few years ago

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2016-04-02 LED Light Ideas For Autos

I bought a few dozen 1 watt LEDs when they were on sale last year at Electronic Goldmine.  They go on sale periodically, for well under a dollar each in a package of 5.  A while back they offered daylight but recently they have all been warm white. These are surface mount, so they are

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2015-10-29 Joule Thief Brightness Measurements

It’s been awhile since I blogged this, so I may be saying what I’ve already said before.  But I get comments from others about how to make measurements of the LED brightness.  A recent one is in the comments of an older blog.  Many Joule Thief builders don’t have the minimum tools needed for some

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2015-06-30 RF Interference and LED Lighting

I talked to a club member about LED lights and how much money they saved in electricity.  But he said he stocked up on incandescent lights before they were banned so he could have them for his radio room.  He has had problems with LED lights causing RF interference with his radios, so he went

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2014-10-13 CRI Rating on New Lights

LED bulb prices are still coming down, but the general public is still not aware of the advantages and still think the prices are too high. And the public is still unaware of the long term savings in electricity from which they’ll benefit. I still see 60 and 75 watt incandescents in dollar stores, which

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2014-08-25 Mini Fluo Light And Another Use For Epoxy Resin

I found some soda straws that are thin and about the same color blue as the blue LEDs I got from goldmine-elec.com.  I got the idea of using a soda straw from Quantsuff at quantsuff.com.  He used two white LEDs in the ends of a short length of white translucent (semitransparent) soda straw to give

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