From: phil_a@tpg.com.au   
      
   "Patrick Turner" <   
      
   > There IS BULLSHIT at this link about measuring resistance of tranny   
   > windings.   
   > Just ignore ignore it all.   
   > Using any kind of meter on any tranny does no temporary or permanent harm   
   > to   
   > properties of windings or core.   
   >   
   > ** Really ?   
   >   
   > Bet you have never even seen an amorphous steel core or worked much with   
   > microphone transformers that use materials like mu-metal.   
   >   
   >   
   > OK, 99% of ppl here will never have experience with fancy core materials   
   > where a small amount of Idc used to measure coil resistance may upset the   
   > magnetic properties.   
   >   
   > For everyone here, transformers they encounter have GOSS or NOSS cores   
   > with / without air gaps and tiny amounts of applied DC by meters changes   
   > nothing.   
   >   
   > Your post indicates your shortage of knowledge on the subject. Please   
   > expand, and tell us under what circumstances measurements could affect   
   > magnetic properties.   
      
      
   ** Microphone transformers are  NORMALLY  made with Mumetal laminations -   
   which allows the core to be small and the number of turns practical. Fancy   
   ones might have amorphous steel in them.   
      
   Both materials are  VERY easily magnetised and this immediately changes   
   their properties such that primary L drops like a stone. A couple of mA in a   
   winding with hundreds of turns is enough in some cases.   
      
   Demagnetising the core with low frequency current is easy enough, but beyond   
   the resources of the average user.   
      
   Tape heads have a similar problem too.   
      
      
      
   ....  Phil   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)