how to calculate the source resistance of function gen?

Discussion in 'General Electronics Chat' started by simpsonss, Mar 17, 2011.

  1. simpsonss

    Thread Starter Active Member

    Jul 8, 2008
    173
    0
    hi,

    I have an function generator and now i'm working on the basic BJT amplifiers. But in the calculation i need the source resistance of the function generator. Does anyone know how to measure or calculate the source resistance of the function generator?

    thanks you.
     
  2. Wendy

    Moderator

    Mar 24, 2008
    20,766
    2,536
    Measure the output without a load, measure the output with a known load. You have a voltage divider equation.
     
  3. jt6245

    Member

    Feb 18, 2011
    21
    3
    Same as above BIlll mention. When the output voltage droped half of its voltage,then the loaded resistor is equal to the output resistance of generator.
     
  4. nomurphy

    AAC Fanatic!

    Aug 8, 2005
    567
    12
    Quality generators are designed to drive 50 ohms, which is why it is necessary to halve the output voltage setting/reading when driving much higher (>> 50 ohms) loads.
     
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