This Joule Thief uses three SS8050 high current transistors, each having a 333 ohm bias resistor (actually three 1k resistors in parallel). At less than a half volt, it gobbles battery current, 49 mA at 0.42 volts. That is a lot more than the typical JT, which drops to a very low current as the
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This JT uses a larger core that is typically found in low frequency applications such as EMI and RFI suppressors. This toroid has high permeability so it doesn’t take many turns to give a high inductance for a JT. The FT87-75 can be found at Surplus Sales for a dollar or so apiece. The 2SC2500
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Paul suggested this Wikipedia article. I quote: I remembered these, having seen one in action, and always wanted one. I think you might be interested. Perhaps that is why I am interested in JTs. There is more than a simple parallel. http://en.wikipedia.org/wiki/Hydraulic_ram When I was a kid, one of my dad’s customers died and his
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The conventional Joule Thief uses a single cell at 1.5V for power. It also typically uses a coil that has both windings the same number of turns. This means that the voltage across the primary, which is also the voltage across the LED, is the same as the voltage across the feedback winding. Almost all
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A question a Youtuber brought up made me think about going to the opposite extreme from the one I normally pursue: trying to get a Joule Thief to run at very low power. Normally I would try to maximize both the light output and efficiency. I started out with a run-of-the-mill Joule Thief having a
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One of my email correspondents and botmaker, Bill Sherman, had made some Joule Thiefs inside of a jar, but this Instructible uses diluted fluorescent ink from a Highlighter pen to diffuse the light into various colors. That’s quite a nice idea, and gives the light a very dispersed and colorful look. What I would like
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I bought some ‘high current’ chokes from Jameco, P/N 642855, which are 390 uH. They’re bigger than average, and mount axially; in other words the leads are at opposite ends of the cylindrical package. They are made by winding relatively heavy copper wire onto a ferrite bobbin. The bobbin is then covered by a piece
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