Added: 2 years ago
From: jeannacav
Views: 25,434
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  • the circuit you built is just a basic switching power supply. They are used all over the place in appliances. The L stands for inductor, The circuit just boost the voltage from a battery. As a battery runs out, the voltage on the output decreases so it can no longer supply as much current to the led and series resistor. . Your circuit is just increasing the voltage and since v/r = i, its allowing more current to flow through the led and its series resistor by stepping up the voltage.

  • why the hell you placed resistor in series with battery when you could just increase base resistor and adjust current to whatever you like without any efficiency loss

  • .

    ...OOO... O ...OOO...

    .

  • Putting the resistor in series with the battery causes most of the battery power to be wasted across the resistor. Instead, the base resistor can be increased to reduce the base bias, which reduces the output current to the LED. I've used as much as 100k or even more to reduce the JT output to a low level. Some experimenters use a 10k pot in series with the 220 ohm resistor to allow the output to be continuously varied.

  • Hi jeannacav,

    Thank you for the explanation!

    My apologies for not answering soon enough.

    Kind Regards

  • gut

  • I guess the answer is 4.

    2 wires are made into the bifilar which is the 'primary' of this ckt. The joule thief works with that just as it is. It is the same as a center-tapped single wire, but we change the number of turns so often, it makes things more clear to call them separate wire names. 'Base coil' and 'Collector coil'.

    Then there are 2 more wires which are true secondaries.

    S1 has 74 Turns

    S2 has 21 Turns.

    I hope this makes sense, now.

    ...because there are more toroids to come!

    jeanna

  • Hi V2DAY,

    The secondary is not attached electrically at all. It is- they are both- wound around the same toroid as the bifilar primary. So, when the bifilar primary gets turned on, the magnetic field inside the toroid moves around and spikes etc, and that makes the electricity pour out of the wires and spike in turn.

    Thanks for asking,

    jeanna

  • Nice one Jeanna.

  • Thanks GBluer

    and

    jdcmusicman

  • This is some good stuff

  • Thanks, Bill.

    Wow, that was fast! I was just about to post the link.

    I am glad to hear it is understandable. Very glad.

    jeanna

  • Jeanna:

    Very nice and very well done, again. I hope many people see this and give it a try. You are helping show folks that there is more to a JT circuit than previously thought. Excellent work.

    Bill

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