From: bill.sloman@ieee.org   
      
   On 1/12/2025 5:32 am, Cursitor Doom wrote:   
   > I posted this for opinions on S.E.R so apologies to those like Jeff   
   > who frequent both groups. SED's got a wider readership, so I thought I   
   > might as well ask here as well.   
   > I'm just wondering if this damage was due to over-current or just a   
   > manufacturing defect. It still reads its advertised value of 1200   
   > ohms. What does the Panel think?   
   >   
   >   
   > https://disk.yandex.com/d/ommuYJD2ZKsW8A   
      
   If it is a carbon film resistor, you could be seeing the result of a   
   massive over-voltage that created a hot channel through the carbon film.   
      
   The hot channel could get very hot and boil the paint directly above the   
   channel, but once the volts went away the carbon film would cool down   
   again, and the carbon in the hot channel would have exactly the same   
   resistance as it had had before.   
      
   This is the reason that carbon film and other negative temperature   
   resistance materials aren't used in intrinsically safe circuits.   
      
   You want something that will get blown away and create an open circuit,   
   rather than than something that can dissipate an unlimited amount of   
   energy after it has been overloaded.   
      
   --   
   Bill Sloman, Sydney   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)