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Testing Transistors With Digital and Analogue Multimeters.

Discussion in 'General Electronics Discussion' started by HellasTechn, May 7, 2016.

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  1. HellasTechn

    HellasTechn

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    Apr 14, 2013
    Hello !

    I have a silly question of which the answer i am sure is simple. Why when testing transistors with DMM we put positive probe to P side and negative to N side while with AMM we go reverse (negative to P side and positive to N side) ?

    Thank you !
     
  2. BobK

    BobK

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    Jan 5, 2010
    What settings are you using on the multimeters? If using a diode check setting, it should be + to P - to N, but if using a resistance setting, the opposite.

    Bob
     
  3. duke37

    duke37

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    Jan 9, 2011
    Because of the circuit in the analog meter, The red lead is negative. Doubtless this simplifies the switching.
     
  4. HellasTechn

    HellasTechn

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    Apr 14, 2013
    I use the diode mode for the DMM and resistor mode (usually mid scale like x10 or x100) for AMM
     
  5. dorke

    dorke

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    Jun 20, 2015
    Like @duke37 said it is because the older Analog meters have the internal battery positive feeding the (-)black lead.
    Newer Analog Meters(and AVOs) and Digital ones have it connected the conventional way positive to (+)RED.
    So for analog meters you never know before you actually test the polarity or look at the schematics of the meter.

    AMM.jpg
     
  6. HellasTechn

    HellasTechn

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    Apr 14, 2013
    That makes sense.
    Thanks for the info :)

    Have you noticed that With an analogue Multimeter you can more reliably test components like transistor's specially darlington and Fet's ?
     
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