measuring superimpose voltage

Discussion in 'Homework Help' started by Thevenin's Planet, May 16, 2011.

  1. Thevenin's Planet

    Thread Starter Active Member

    Nov 14, 2008

    This is about measuring superimposed voltages. I notice when I reveres the meter probs I get a different voltage on the a.c. scale.Addionally, the voltage source one is a 9 volt battery when measured at a different probe position it register 0.6 rms and the meter reverses.This puzzle my understanding.I need some opinions from the A.C.C. community.Below are the following measurement that was done on a Radio Shack FET multimeter,non Digital.

    a.c. meter scale---- Note :The D.C. Battery is 9 volts not 1.5 volts

    VR1 = C+,D-| Results is 3.3 rms |forward deflection
    VR1 C-, D+| Rsults is 23.94 r.m.s.| Forward Deflection
    Vs1 A-,B+| Results 0.6 r.m.s. Meter Deflection Reversed
    Vs1 A+,B-, | Results is 19.8 r.m.s Meter Deflection Forward
    Vs2 A-,B+,| Result is 12.06 r.m.s|Meter Deflection Forward

    D.C.V. Scale

    VR1 C+,D-,| Results is 9.2 D.C.|Meter Deflection is Forward
    VR1 C-,D+,| Results is 9.2 D.C.|Meter Deflection Reversed
    Vs1 A-,B+ | Results is 9.25 D.C.|Meter Deflection Forward
    Vs1 A+,B- | Results is 9.2 D.C. | Meter Deflection is Revered
    Vs2 A-,D+ | Results is 0.00 |Meter Deflection is 0.00
    Vs2 A+,D- | Results is 0.00 | Meter Deflection is 0.00

    I understand this elementary level and my ignorance about this subject can become very boring but endurance is the key to overcome frustration.
    Last edited: May 18, 2011
  2. Jony130

    AAC Fanatic!

    Feb 17, 2009
    I read somewhere about this "phenomenon" that very cheap Chinese multimeter's can behave in a way that you described.
    But I don't know why