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jimluschen

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  • Maxwell House Wireless Antenna

    I think you mean 2.4GHz, not 24GHz

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  • Easy Joule Thief Circuit

    First, an inductor is a two-terminal electrical component. Since this thing has four terminals, it can't be an inductor. Also, the dots and dashed lines indicate "transformer". That is what is drawn in the schematic.Of course, a transformer is just two inductors with linked magnetic flux. So while your component isn't "an inductor", it is "two inductors". Or really "two coupled inductors". Confusion arises because common transformers step voltages up (or down). But a transformer can have an equal number of windings in the primary and secondary, in which case it does not increase or decrease voltage. This type of transformer is often called an isolation transformer.So you are right, this transformer would not boost voltage. But it would coupl…

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    First, an inductor is a two-terminal electrical component. Since this thing has four terminals, it can't be an inductor. Also, the dots and dashed lines indicate "transformer". That is what is drawn in the schematic.Of course, a transformer is just two inductors with linked magnetic flux. So while your component isn't "an inductor", it is "two inductors". Or really "two coupled inductors". Confusion arises because common transformers step voltages up (or down). But a transformer can have an equal number of windings in the primary and secondary, in which case it does not increase or decrease voltage. This type of transformer is often called an isolation transformer.So you are right, this transformer would not boost voltage. But it would couple the two sides of the circuit, while providing a phase shift between them. In this circuit I suspect that phase shift is the most important feature of the transformer, allowing the collector and base to see the same voltage vs. time signal, but with a phase shift between them. That phase shift is what causes the circuit to oscillate. You might also think of the transformer as the feedback path that provides the necessary phase-shifted feedback from the collector (output) back to the base (input).Oscillators are tricky circuits, and in my opinion their designers are magicians (especially those YIG oscillator guys). But in any case, LTSpice says your circuit works. I am attaching a screenshot of the analysis I ran of it. The inductances of the transformer is just a wild guess, so the oscialltion frequency is also.Jim

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  • Easy Joule Thief Circuit

    Yes, it's a play on the term "jewel thief"

    It's more properly called a toroidal transformer.

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  • Building My Dream Desk With an Integrated Computer

    I calculate 40 board feet of 8/4 walnut (10' x 24" x 2" = 10*2*2=40)

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  • jimluschen commented on AdrienR's instructable Screw Sorting Machine
    Screw Sorting Machine

    Hey Gregg, how can I get a 5-gallon bucket of hardware?

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  • How to Make a Guitar Pedalboard

    The wood choice and the box joint are the best parts of this design, you did a great job with that. But I did not see a link to a box joint jig tutorial, although you reference one.

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  • You mean 33kWH per day? And the water heater is electric, not gas?

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  • I roll all my tee shirts and put them in drawers. They fit fine, and if you load on one side and remove from the other they all get the same amount of washing

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  • I'd think that a cold dry day would make static a problem, where you'd potentially damage the oxide gate layer and destroy the MOSFET when you touched it (think big spark jumping from finger to doorknob).How is your reliability?

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  • Thanks for the response. I've seen those electric heating elements glow orange-red when they are at full blast with no pots on them, my Grandma's old GE stove did that often. From this link below and my memory I would guess that they reached almost 900C:http://www.blksmth.com/heat_colors.htmSo I think building a K-23 firebrick enclosure around such a heating element might work. I'd agree with you and TheCrafsMan that fixturing would be a lot more difficult, though. But my goal is to repair a tiny item that I could never hold in place accuately by hand, so I already need to machine some sort of fixturing. I guess I'll need to make it from steel, not aluminum.I think I'll try it, if it fails miserably I'll let you all know!

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  • Do you have any thoughts on using some sort of oven for the heat source instead of a torch? I was thinking of building a small oven with fire brick and a cal rod from an old electric cooktop.

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