curve tracer and capacitor question

Discussion in 'General Electronics Chat' started by lokeycmos, Jul 20, 2012.

  1. lokeycmos

    Thread Starter Active Member

    Apr 3, 2009
    432
    7
    i saw an electronics repair technician today testing for bad electrolytic caps. he was using a huntron tracker 2000 curve tracer. i was kinda confused because he was putting one lead on the leg of the capacitor and the other lead on the metal casing on top of the cap. if it is an ellipse it is good, any other waveform means its bad. the thing i was confused about was why he was putting a lead on the casing of the cap? i just measured from casing to each leg with my ohm meter and im getting double digit Megaohms. this shows that the case is NOT in common with either leg. Please Explain!!TY!!
     
  2. Lundwall_Paul

    Member

    Oct 18, 2011
    220
    19
    I have attached a manual for a huntron tracker. Not your model number but it explains the waveforms.
     
  3. lokeycmos

    Thread Starter Active Member

    Apr 3, 2009
    432
    7
    thanks for the reply. but my question is, why is he touching the casing of the capacitor if the casing is not common with either lead?
     
  4. vk6zgo

    Active Member

    Jul 21, 2012
    677
    85
    I find that strangely disturbing!:D
    Occasionally,you will find an Electrolytic cap where the case is connected to one side of the capacitor,but it is not common,except in the case of multiple caps in one package.

    I have never thought Huntron Trackers were worth using,but others swear by them,& seem to have good results.
     
  5. BSomer

    Member

    Dec 28, 2011
    433
    106
    I have come across some electrolytic capacitors where the "-" lead is tied to the body. These have mostly been "memory" capacitors, like 5.5V 0.1uF... Most of the time though the leads are isolated from the body.
     
  6. vk6zgo

    Active Member

    Jul 21, 2012
    677
    85
    As an addition to my earlier comments:

    Single Electrolytics with one side connected to the case were commonly used as filter capacitors back in the days of "5 valve mantel radios"(At least,in Australia).
    It's so long ago,I had forgotten them!
     
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