See Note at bottom. Years ago I bought a shake flashlight and it was nearly worthless. I shook it for quite awhile, and as soon as I stopped, the LED went dim. So how am I supposed to shake the light and try to aim it as something that needs light? And if it wasn’t
(Read More…)
Well, the LEDs I ordered more than a month ago have finally arrived. They are 10 Watt(!) 900 lumens from Electronic Goldmine for $6 (USD) apiece (I checked their website and they seem to be sold out). The reason why it took so long was mostly my fault. They were shipped to my previous address,
(Read More…)
In a comment, Metis asked: How can I reliably measure and/or control the output voltage of the JT? I’m currently trying to build a small power supply to recharge a Li-ion battery and I’d prefer to be able to keep the output voltage at (or rather below) a known level rather than invest in a
(Read More…)
I answered a Yahoo question: is joule thief fine as grade 12 physics final project? Additional Details Is the joule thief circuit appropriate as 12th class final physics project? I have made a joule thief circuit (http://www.youtube.com/watch?v=gTAqGKt64… as 12th class’s final project. Should my high school add this in my transcript for the Universities? Will
(Read More…)
In my earlier blog, yesterday I discussed using a 1 Farad capacitor to hold enough charge to run the flasher for several hours, from dusk to midnight or later. I checked Mouser’s parts and found a 1F 2.5V capacitor from Bussman for about 2 dollars in single unit quantities. Kind of expensive but cheaper in
(Read More…)
I’ve seen a lot of Xee2’s xee2vids on Youtube, but I don’t remember seeing this one before. It’s dated Sept 2011, so it’s more than 2 years old. The Joule Thief flasher obtains its power from four red LEDs connected in parallel, which are used as solar cells and charge a 10 thousand uF capacitor.
(Read More…)
One thing I’m glad to see is that many of the problematic parking lot lights have been replaced. These are the ones with the big, pinkish yellow light in them that has what I call the ten off, ten on syndrome. Once the light has spent a half hour heating up, it stays lit for
(Read More…)
I came across a schematic of a “Joule Thief” circuit, actually a two transistor LED V boost circuit, on OverUnity.com. This is part of a garden light, and has a solar cell to recharge the battery, and the battery to store the electricity until after dark. The schematic, dated 10/16/2013, was drawn partially upside down
(Read More…)
Danny left a comment about powering a 12V, 3 Amp LED light with super capacitors. He asked for my thoughts on this. I’ve made higher power Joule Thiefs and I’ve tried to power several things with super capacitors and although my experience with this isn’t as extensive as my experience with JTs, I think I
(Read More…)
I touched upon this subject in my late, great watsoneblog, but not since then, I believe. What I came up with back then was simple and effective. I wanted to change the abrupt turn on and turn off of the LED into the much slower turn on and turn off of an incandescent light bulb.
(Read More…)
