I built this circuit long ago and I can’t remember what I intended it to be used for. It’s kind of different. The CdS photocell is glued into the end of a 3/8 inch O.D. by 1 inch long piece of black plastic, probably cut from the body of a cheap ball point pen. This
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In the world of Electronics, as in the Real World, there are those who try to manipulate the truth to take advantage of those who have a limited understanding of its underlying principles. We will call these manipulators scammers. One scam that I often see is when an experimenter tries to get a LED circuit
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2011 Jun 30 Germanium Supercharged JT Note: links are broken until I replace them. Peter asked me if my Supercharged Joule Thief would be a good circuit to use with AC128 germanium transistors. But I admitted that I had never tried using germanium transistors in a SJT. So I took a SJT that was already
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I saw this schematic for a kit that was sold at one time. It uses 2 transistors, and the author claimed that it was 70 percent efficient. I wanted to build one to see what my results would be. Technically it’s not a true Joule thief, which uses only one transistor and has a two
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I bought some cheap LEDs from a vendor on eBay, and found that most of them had air bubbles inside of the clear epoxy that makes the lens. This causes the light to scatter, and the LED will not meet the specifications that are given for the light beam output. They still put out bright
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I found something that drew my attention, a Joule Thief that operates on less than a half volt and uses a silicon transistor. Here is a short Youtube video of a circuit operating at less than 1/4 volt, and it says it is using a BC107, which is silicon. I said to myself at first
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I’ve talked about this before: the Joule Thief has certain vulnerabilities that need to be considered when making a new design. Suppose we build a simple conventional JT, with a single LED and a 1.5V battery. The coil has two windings, each the same number of turns, probably wound bifilar – the windings are wound
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Full Brightness Myth – The typical JT (Joule Thief) uses a single transistor, draws 80 milliamps from the 1.5V battery, and puts out up to 20 milliamps to the 5mm white or blue LED. Let us consider this 20 milliamps “full brightness” or “full brilliance”, which is a term often used but has no quantitative
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I assembled a two transistor LED driver buck converter for dropping the 12V input down to the 3.2 volts needed for the LED. My problem seems to be that the circuit wants to act like a simple 22.2 mA current limiter, as if I took out the inductor and capacitor (the D1 is reverse biased
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From Watsonseblog Jan 2010: Very odd LED dropping resistor – edible! There are several others of the same genre on Youtube but this one has LEDs. Cool, an edible resistor! I remember that the stores sold a hot dog cooker that was just s simple box with a drawer and electrodes. It took about a
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