610c7929   
   From: mynamespacedbydots@xs4all.nl   
      
   "Engineer"  wrote in message   
   news:09b70d94-fe12-41f0-929b-8abe431b6fb5@fx14g2000vbb.googlegroups.com...   
   >>> Just by the way: If a pot is set to midpoint, and source output   
   >>> impedance   
   >>> is low, then output impedance of the wiper is R/4, not R/2.   
      
   >> Just by the way: R/4 at wiper midpoint only when it's a linear pot, not   
   >> log.   
      
   >Alex, right, of course! With a zero Z source, you get 25K in parallel   
   >with 25K at mid rotation of a linear pot, a quarter of the original   
   >50K... at some other place further around for the log pot that I   
   >used.  My fault, in too much of a hurry... Thevenin rules!   
   >Cheers,   
   >Roger   
      
   Depending on a pot's taper and quality, for a log pot   
   ccw tap to wiper midpoint is approximately R/10.   
   With a zero Z source and approximately Rx0.9 cw tap   
   to wiper midpoint you'd get around R/11 wiper Z.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)