From: pallison49@gmail.com   
      
   Phil Hobbs wrote:   
   >   
   >  Phil Allison wrote:   
   > > Phil Hobbs wrote:   
   > >   
   > >>> John Larkin wrote:   
   > >>>>   
   > >>>>   
   > >>>> It's a nuisance to desolder caps to test them, especially   
   > >>>> surface-mount parts.   
   > >>>>   
   > >>>   
   > >>>   
   > >>> ** There is NO need to do that for ESR testing of electros !!!.   
   > >>>   
   > >>> ESR meters use low currents and high frequencies ( 100kHz typ ) to asses   
   the impedance near the component's series resonance.   
   > >>>   
   > >>> Electro failure is indicted by an unusually high reading, compared to   
   similar parts.   
   > >>>   
   > >>>   
   > >>>> It's easier to scope the circuit and look for   
   > >>>> symptoms of a bad part.   
   > >>>>   
   > >>>   
   > >>>    ** Not for ESR it isn't.   
   > >>>   
   > >>>   
   > >>> ....  Phil   
   > >>>   
   > >>   
   > >> Depends where in the circuit. In a power supply or audio output,   
   > >> sure--there are probably PN junctions isolating the cap from the rest of   
   > >> the circuit when it's powered off.   
   > >>   
   > >   
   >>   
   > > ** There is no need for any such isolation the test voltage appearing   
   across the electro is lower than any junction threshold.   
   >   
   > Which was my point.   
   >   
      
   ** But not mine. A junction can be in *parallel* with the electro with no   
   effect on ESR measurements. That is not isolation.   
      
      
   > You can measure them essentially in isolation.   
      
      
   ** Not only have you never used one, but you are stubbornly refusing to think   
   the situation through.   
      
   What makes these meters SOOOO useful IS their ability to read ESR accurately   
   while the cap IS left in circuit.   
      
      
   >   
   > >   
   > >   
   > >> In a low-Z RC circuit, not so much.   
   > >   
   > >   
   > > ** Complete bullshit.   
   > >   
   > >    Obviously Hobbs has never used one.   
   >   
   > Do tell, go on, don't hold back now. ;)   
   >   
      
      
    ** Hunch confirmed.   
      
   > Cheers   
      
      
    ** Piss off you pathetic troll.   
      
      
      
   .....   Phil   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)