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???
03/29/05 14:18
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 		 #90592 - Of course...
Responding to: ???'s previous message
Michael said:
May I be so bold as to propose an alternative (Or minor modification) to Kai's 220V detection circuit?

Of course, you may, dear Michael! Discussion is the key issue here...

In applications were I use bipolar transistors for switching purpose I use rather high base currents to keep the collector emitter saturation voltage as low as possible. Assuming typical values from datasheet allows the use of somewhat lower base currents, but I know from experience, that a certain percentage of transistors do show somewhat higher saturation voltages, which can be pushed to allowable values by increasing the base currents. This is my excuse for the rather high base current into the BC550B.

Kai



List of 37 messages in thread
TopicAuthorDate
Detecting 220V            01/01/70 00:00      
   AC-input optoisolator            01/01/70 00:00      
      Thanks!            01/01/70 00:00      
   I'd use a transformer            01/01/70 00:00      
      Why the transformer?            01/01/70 00:00      
         not necessarily relative to ground            01/01/70 00:00      
            Neon + LDR?            01/01/70 00:00      
      I read the Datasheet of MID400            01/01/70 00:00      
         MID400            01/01/70 00:00      
            That's strange, Erik!            01/01/70 00:00      
               recognized            01/01/70 00:00      
                  "You're Forgiven, Not Forgotten..."            01/01/70 00:00      
   Transformer isolation recommended            01/01/70 00:00      
      May I Modify Your Suggestion Kai ??            01/01/70 00:00      
         Of course...            01/01/70 00:00      
            Kai, Michael - what about ready-made            01/01/70 00:00      
               Could also solve the problem            01/01/70 00:00      
                  One futther on the Wall Wart Idea...            01/01/70 00:00      
                  Wall Wart            01/01/70 00:00      
      Is optoisolation fundamentally dangerous            01/01/70 00:00      
         No, not fundamentally, but...            01/01/70 00:00      
            What is dangerous?            01/01/70 00:00      
   A different view            01/01/70 00:00      
   I'm sweating... ;-)            01/01/70 00:00      
      wallwarts            01/01/70 00:00      
         Oh, I see!            01/01/70 00:00      
            that's a lot of fuses            01/01/70 00:00      
            A bit clarification required            01/01/70 00:00      
               Forgot to press the "Post" button            01/01/70 00:00      
                  enough, yes - that much, no            01/01/70 00:00      
                  Existing commercial products            01/01/70 00:00      
                     Quite a large project, indeed...            01/01/70 00:00      
                        Mains control            01/01/70 00:00      
                           I know...            01/01/70 00:00      
                        Safety issues            01/01/70 00:00      
   Another idea, using a coil and an op-amp            01/01/70 00:00      
      RE: Another idea...            01/01/70 00:00      

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