From: pallison49@gmail.com   
      
   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.   
      
      
      
   > In a low-Z RC circuit, not so much.   
      
      
   ** Complete bullshit.   
      
     Obviously Hobbs has never used one.   
      
      
      
   .....   Phil   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)