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c3r14l.k1l4

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Posts posted by c3r14l.k1l4

  1. Nop. Sorry...

    You explained me it's functioning... and I already knew that... I just want to know how to calculate the source voltage regarding the one applied to it's gate.

    Check this:
    123132.png
    In the BJT circuit the emmitter is 5-0.7V so aprox 4.3V. In the FET one the source is 5-X=1.431 so X=3.569V? Where does this value come from? Is it the pinch voltage? I think so... just to make shure...

  2. Hi,

    you'll need a supply with the voltage the schematic was designed to. About it's current, the more the better (the circuit will only use the required amperes). The problem is that if your transformer has less power, the circuit will cause the transformer to dissipate more power (incresing it's temperature) and therefore... kaput  :P

    Don't forget to have a rectifier bridge with support for more than 1.5x the maximum current you'll need.

  3. Greetings,

    I'm new here and this is my first post. All my electronics knowledge has been built from experience and books and I intend to help whenever I can. But as I'm not God I've got some doubts.

    One of them wich is bugging me is how to get a FETs source voltage value. For instance, we know that in a BJT the emmitter is always the base - junction drop voltage (~0.7V), but in the books I can't find a similar relationship for the FETs. Only the drain current in function of the gate voltage (the parabola function).

    Can anyone explain this to me?
    And... sorry for my english, as it's not my native language...
    Cheers!

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