I got an email from QS saying that he posted a Joule Thief Beeper to his web page, about 2/3 of the way down. I think it might make a metronome if the speed was adjustable. basically it’s a two transistor circuit with a single coil made from the voice coil of an 8 ohm
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My comment to a blog found here. A very common way of boosting voltage does not use an inductor. Instead it uses a ‘charge pump’ or switched capacitor, or flying capacitor. You can buy the Fair-Rite 2673002402 core for $0.12 (U.S.) apiece, and 12 turns of 24 AWG (0.5mm) insulated telephone wire can be scrounged
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I found a Youtube video with a two transistor circuit (some mistakenly call this a Joule Thief) that is used a a voltage booster to give 9V from 1.5V or 3V. He shows the schematic of the circuit at the end. I had a similar circuit in my late great watonseblog. But I think
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I built this in April, 2003. It uses a single AA cell and a 2 transistor V Boost circuit, see pic for the link.
Whilte I was writing my blog about Homemade Components, I visited the Wikipedia page about the cat’s whisker detector, the active component in the crystal radio. I read the intro paragraph “A cat’s whisker detector (sometimes called a crystal detector) is an antique electronic component consisting of a thin wire that lightly touches a crystal
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This LED light is identical to the others with white LEDs, but I used red, green and blue LEDs for a Christmasy effect. The schematic of the circuit is on a post-it inside of the lid.
I tack soldered this phase shift oscillator together and used a 2N7000 MOSFET for the PSO. The second transistor in the upper right is a 2N4401 being used as an emitter follower to drive the LED. The LED would draw too much current and load down the oscillator – the PSO has to have a
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This is a pic of the ring oscillator I built in Feb 2009. It’s the same as my earlier blog, but it has three LEDs per stage, so the supply voltage has to be higher. I’m going to try to upload the few second video. This was taken from the back because the LEDs were
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Bespoke – The experimenter sometimes may have a difficult time obtaining parts. In a pinch, he may be able to make his own parts. This generally applies to passive components such as capacitors, inductors, resistor, but on occasion may extend to active components too. Coils – Most of use who have built Joule Thiefs are
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Surge Protectors – Pros and Cons I was just sitting there, working on something, when I heard a loud BZZZT and immediately I smelled smoke. I couldn’t tell where the burning smell was coming from. I became concerned to the point of panic that there would be a fire breaking out any second. I couldn’t
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