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???
09/05/06 17:21
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 		 #123694 - it depends on the source ...
Responding to: ???'s previous message
I remember a case, back in the late '70's, when there was a shortage of 7812's because of the rush on 5-1/4" floppy drives and powered enclosures for them. My client bought several thousand of them from a well known and popular component vendor which no longer actively deals in components. Our incoming inspection showed that, of the several thousand regulators we'd purchased, NOT ONE regulated within the 5% tolerance. All of them regulated about 7% low, but otherwise functioned satisfactorily. We were able to recover from the problem easily enough but it was certain that we'd never again buy parts from that vendor.

RE




List of 44 messages in thread
TopicAuthorDate
78x05 output voltage tolerance            01/01/70 00:00      
   5%            01/01/70 00:00      
   Selection needed...            01/01/70 00:00      
      5%, 10%, it's all there            01/01/70 00:00      
         for decades, 5% was "standard." What's changed?            01/01/70 00:00      
         What standard do you mean??            01/01/70 00:00      
            "if"            01/01/70 00:00      
               Don't you test your circuits?            01/01/70 00:00      
                  it's already a pain...            01/01/70 00:00      
                     if you do, I'll take my cap off to you :)            01/01/70 00:00      
                  Consider the specifications            01/01/70 00:00      
   is it a Microchip supervisor?            01/01/70 00:00      
      the conclusion            01/01/70 00:00      
         No such thing as luck in any acceptable design sce            01/01/70 00:00      
            everyday we learn something...            01/01/70 00:00      
         Check it with a >5.0V outputting 7805!            01/01/70 00:00      
            it will work...            01/01/70 00:00      
               oh 'testing'            01/01/70 00:00      
            Getting more than 5 v from 7805            01/01/70 00:00      
               I would use a resistor instead of a diode            01/01/70 00:00      
                  see the datasheet, it shows how to do that...            01/01/70 00:00      
                     It's noise, I guess...            01/01/70 00:00      
                        some noise            01/01/70 00:00      
               the u (micro) is only specified to 5.25 or 5.5 Vol            01/01/70 00:00      
   I just had an idea...            01/01/70 00:00      
      Don't go off chasing that rabbit!            01/01/70 00:00      
         digital design practice            01/01/70 00:00      
            Safe side...            01/01/70 00:00      
         Exactly            01/01/70 00:00      
      Getting low output...            01/01/70 00:00      
   get this in your head            01/01/70 00:00      
      Not so fast...            01/01/70 00:00      
         oh, how many designs have failed because            01/01/70 00:00      
            No, no, I have not said this            01/01/70 00:00      
            it depends on the source ...            01/01/70 00:00      
               Yes,...            01/01/70 00:00      
                  There's a critical difference ...            01/01/70 00:00      
                     Of course, there is!!            01/01/70 00:00      
                        whst do you refer to?            01/01/70 00:00      
                           This was in the '70's, before many restrictions            01/01/70 00:00      
                              caught by "legal relabeling".            01/01/70 00:00      
                                 That's not what I remember            01/01/70 00:00      
                                    continuing the story            01/01/70 00:00      
                                       The way it used to work ...            01/01/70 00:00      

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