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using current to measure a time

Discussion in 'Electronic Basics' started by Panther, Dec 1, 2005.

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  1. Andy Baxter

    Andy Baxter Guest

    John Fields said:
    I think he's been given a practical assignment in school physics /
    electronics, but isn't sure how to do it, and doesn't really want to do
    the experiment anyway.

    To Panther - if you don't do the experiment, you're cheating yourself. The
    whole of science is based on trying out your ideas against the real world
    by testing them to see if they work, so if you don't do that bit, you're
    not really learning science.
     
  2. Panther

    Panther Guest

    To Panther - if you don't do the experiment, you're cheating yourself. The
    Nononono

    I am doing the practical it's just that i have ONE WEEK to do it in and if I
    just measure the voltages then I won't have time to work out the time, so if
    I could record the voltages and do the calculations later using some formula
    it would bebetter.
     
  3. Panther

    Panther Guest

    It seems to me that by your not cross-posting, by your off-handed

    I'm sorry but I cannot do those complicated solutions, I am poor at
    practicals/electronics. Simpler circuits are better.
     
  4. Andy Baxter

    Andy Baxter Guest

    Panther said:
    It shouldn't take you long to work out the times - it's a simple formula.
    Look up 'capacitor', 'exponential decay', and 'time constant' on google.
     
  5. Rich Grise

    Rich Grise Guest

    Then your best advice is to go back to school, but read the textbooks
    this time. There are no simpler answers to your question if you refuse
    to become educated in the methods and background involved.

    The ball is in your court.

    Good Luck!
    Rich
     
  6. Rich Grise

    Rich Grise Guest

    Well, record the damn voltages then!

    Set up your thing, with a DC power supply and series resistor to the
    swinging ball. Connect a capacitor from the stationary ball to ground.
    Measure the voltage at the capacitor. Any ordinary DVM should be able
    to do that - in the US, they're US$9.95. Write this voltage down. It
    doesn't matter what it is, just write it down. Swing the ball. Measure the
    voltage at the capacitor, QUICKLY! Write that number down.

    Record the value of the resistor and capacitor in step 1, and use
    the equation for a charging capacitor to find out how long they were
    touching.

    If I gave you any more detailed of an answer than that, I would be
    doing your labwork for you, which is even worse than doing your
    homework for you.

    Get up off your dead butt and learn something.

    If you only have a week left, and haven't by now learned the material,
    then maybe you should get into politics or something.

    Good Luck!
    Rich
     
  7. Panther

    Panther Guest

    OK I will do that thanks.

    But you should really be blaming the school, not me for the lack of time. We
    were given the assignments about a week ago, and expected to think of
    something in a few days. I get practically no help from the teacher anyway.
    I had to wait for ONE HOUR FOURTY FIVE MINUTES to get help for FIVE minutes,
    because the teacher has to run out somewhere. I hope the next year
    coursework involves no practical.
     
  8. Andy Baxter

    Andy Baxter Guest

    Panther said:
    Good luck with it,

    andy.
     
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