Fun family science project — electric lighting from trash

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6 Responses to “Fun family science project — electric lighting from trash”

  1. Itsumishi says:

    Breaking Bad taught me this lesson well! (video 9)

  2. Sam Archer says:

    So you can run a 3v LED, at (essentially) half-brightness, from a 1.5v battery.  Useful in a limited extent, I suppose, but I don’t know that there’s a lot of application for this beyond flashlights…

  3. SamSam says:

    Some of you are thinking “wait, maybe it enables you to use a single 1.5 volt battery to light a 3V LED instead of the usual two, but doesn’t it just make that battery last half as long? Great question, but the answer is that the Joule Thief [...] actually is more efficient than using a battery directly because it PULSES the energy to the LED

    Uhhh, so it enables you to use a single 1.5 volt battery to light a 3V LED instead of the usual two, but it makes the light half as bright.

    That is either very carefully make unclear, or the original author wasn’t clear about it.

  4. KWillets says:

    It’s just a boost converter, like in every single-cell LED flashlight.  It charges a coil, switches it through the load, rinse, repeat.  

    The switching mechanism is fun (induced voltage from a secondary winding into the transistor), but it’s unregulated.  

  5. cservant says:

    Also electrical NOISE.  Keep it away from or shield sensitive equipment.

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