home bbs files messages ]

Forums before death by AOL, social media and spammers... "We can't have nice things"

   alt.engineering.electrical      Electrical engineering discussion forum      2,547 messages   

[   << oldest   |   < older   |   list   |   newer >   |   newest >>   ]

   Message 1,527 of 2,547   
   Tim Williams to All   
   Re: Transistor identification?   
   06 Sep 15 13:03:42   
   
   XPost: sci.electronics.basics, sci.electronics.components, sci.e   
   ectronics.design   
   XPost: sci.electronics.repair   
   From: tmoranwms@charter.net   
      
   "DaveC"  wrote in message   
   news:0001HW.1B9BFB3100248A5811E4F83CF@news.eternal-september.org...   
   > Dead. Other with identical markings measure as NPN. What else to determine   
   > from measurements?   
      
   Find a modest to high voltage supply, add a large series resistor   
   (10k-100k?), and measure the reverse breakdown.   
      
   Wire it as a common emitter amplifier, not really to amplify but just to   
   check bias.  Play with base resistors until you get the edge of saturation   
   for some collector current.  Then double the collector current and do it   
   again.  That'll more or less let you plot hFE(Ic).  Where it drops by half   
   or so is near Ic(max).   
      
   Now you know Vebo, Vcbo, hFE and Ic(max).  Vebo is generally less than 5V   
   for RF parts, so you'll likely have a high fT in that case.  You can set it   
   up with a square wave input to measure t_r, t_f, t_stg etc. if you like.   
      
   Tim   
      
   --   
   Seven Transistor Labs   
   Electrical Engineering Consultation   
   Website: http://seventransistorlabs.com   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)   

[   << oldest   |   < older   |   list   |   newer >   |   newest >>   ]


(c) 1994,  bbs@darkrealms.ca