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Thread: Setting current flexmod p3

  1. #1
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    Default Setting current flexmod p3

    Hi all,
    Congrats for the forum
    Just tested some diodes with my Lab current limited PSU. All goes oK.

    Now, I'm going to connect the diode to Flexmod P3 and adjusting optimal current. (Flexmod is wired to switching PSU, 12V 16,5A)
    I was thinking to connect multimeter (set to 10A) in series with diode...is this the correct way?? Can I damage diode?

    Please see attachment pic.

    Many thanks!!

    Jordi
    Attached Thumbnails Attached Thumbnails test current.jpg  


  2. #2
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    A "Dummy Load" or "Test Load" consisting of 3 silicon diodes and a One to Three Ohm power resistor in series is recommended for beginners (and Experts!) when calibrating any Diode driver. The three diodes each add a 0.6 volt drop to the circuit for a 1.8 volt forward voltage, and the one ohm resistor is there to provide a bit of impedance, as well as a means of measuring current.

    Steve
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    HI Steve,
    Are you referring to connect Load to driver, adjust current, taking off the load and the connecting the diode? Do you have schematics?
    The way I comment, polymeter in series is not ok? so could I damage diode?
    many thanks!!

  4. #4
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    Click image for larger version. 

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    You may use the multimeter in series with the test load. I would NOT use one in series with a expensive diode, unless it was hard wired. Laser diodes are not LEDs, they are very static and current sensitive. If the multimeter lead slips or disconnects, you can kill the diode instantly.

    Above is the test load schematic. In the USA we usually use 1N4007 diode and a multiwatt resistor.

    STEVE
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  5. #5
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    I use to do the same thing steve but I found just putting the amp meter as the load and setting the current works just fine. First I set the bias than I set the main current. When I remeasure the current with the diodes I found I was so close to the right current it didn't matter. Andrew taught me that one.

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