Voltage measurements on Oscilloscopes

Discussion in 'General Electronics Chat' started by dumindu89, Sep 30, 2012.

  1. dumindu89

    Thread Starter Member

    Oct 28, 2010

    If I measure a voltage of a AC voltage source using a 1 MΩ Oscilloscope and let's say the measurement is 200 mV(p-p).
    Then what will be the measurement if I measure the voltage of the same AC voltage source using a 50Ω Oscilloscope? Is it same?
  2. crutschow


    Mar 14, 2008
    Depends upon the impedance of the voltage source. If the source is ideal (zero ohms impedance) then the reading will be the same. If not, then the voltage will be reduced by the voltage divider caused by the source impedance and the oscilloscope impedance.
  3. wmodavis

    Distinguished Member

    Oct 23, 2010
    Crutschow said it. It dependa on the circuit you are measuring which you have provided NO information about. Circuit loading you know. Every test measurement causes some loading of the circuit being measured and affects the measured value. Hopefully it is minimal. If you are measuring something it is your job to understand both the circuit being measured and the characteristisc of the measuring equipment.