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???
02/14/09 14:42
Modified:
  02/14/09 14:44
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 		 #162411 - Do you mean this?
Responding to: ???'s previous message



Imagine, now, how (most of) the current spike is flowing, when the transistor is abruptly turning-on: Out of the plus pole of 47µ cap, through the transistor from emitter to collector, through the LED, through the current limiting resistor and back to the minus pole of 47µ cap. The micro does now only see a small portion of this current spike at its Vcc terminal.
The 100n supports the 47µ, which becomes less effective at frequencies beyond 1MHz.

This kind of power supply decoupling can be really important in noisy applications like multiplexers.

Kai

List of 64 messages in thread
TopicAuthorDate
Help Needed:8051 and BDX54C            01/01/70 00:00      
   Draw it!            01/01/70 00:00      
      How to post a schematic            01/01/70 00:00      
   Reply to Aamir            01/01/70 00:00      
      SPDT switch?            01/01/70 00:00      
   the schematic            01/01/70 00:00      
      ground that emitter            01/01/70 00:00      
      PNP versus NPN            01/01/70 00:00      
         Basic electronics            01/01/70 00:00      
      See if this helps...            01/01/70 00:00      
         the circuit to the left is always on            01/01/70 00:00      
            woops...            01/01/70 00:00      
               so then            01/01/70 00:00      
                  you have options...            01/01/70 00:00      
                  no answer till ...            01/01/70 00:00      
            burning a hole...            01/01/70 00:00      
               Be cool!            01/01/70 00:00      
                  gimme, gimme            01/01/70 00:00      
                  proper current to LEDs.            01/01/70 00:00      
   The only way to use the BDX54C...            01/01/70 00:00      
      LED current - sweeping generalisation            01/01/70 00:00      
      Please explain            01/01/70 00:00      
         Just imagine how this high LED current...            01/01/70 00:00      
            Hence the reason...            01/01/70 00:00      
               I do not think so            01/01/70 00:00      
                  His "please explain" thread proves...            01/01/70 00:00      
                     cant u?            01/01/70 00:00      
                        You need to provide            01/01/70 00:00      
                        Do you mean this?            01/01/70 00:00      
                           Thanks Sir KAi            01/01/70 00:00      
                              10K SPI            01/01/70 00:00      
                                 Meaning of "SIP"            01/01/70 00:00      
                                    A 10K SIP Indeed !!!            01/01/70 00:00      
                                       How it works??            01/01/70 00:00      
                                          Short for what            01/01/70 00:00      
                                          Look again - and think!            01/01/70 00:00      
                                       so, what he has used?            01/01/70 00:00      
                                          Why more schematics?            01/01/70 00:00      
                                             But            01/01/70 00:00      
                                                10k SIP do not connect anything. They add something!            01/01/70 00:00      
                                                   what for 8051            01/01/70 00:00      
                                                      do you EVER bother to read the docs before asking questions            01/01/70 00:00      
                                                         Back to basics            01/01/70 00:00      
                                                      Yes, you will            01/01/70 00:00      
                                                RE: how those eight data lines are connected ?            01/01/70 00:00      
                                             But            01/01/70 00:00      
                                                as seen on the schematic            01/01/70 00:00      
                                             Not all SIL resistor packs are the same!            01/01/70 00:00      
                                                Yes, more than one type of SIL network            01/01/70 00:00      
                              looks exactly like what I would suggest            01/01/70 00:00      
                              Both, but take care...            01/01/70 00:00      
                                 what you think about this?            01/01/70 00:00      
                                    Post link            01/01/70 00:00      
                                       No no            01/01/70 00:00      
                                          Doesn't add up            01/01/70 00:00      
                                    Depends...            01/01/70 00:00      
                              it wont worked....            01/01/70 00:00      
                                 Still Doesn't add up!            01/01/70 00:00      
                                 Then you have done something wrong!            01/01/70 00:00      
                                    experimenting "wildly" ....            01/01/70 00:00      
                                       Basic electronics            01/01/70 00:00      
                                    You are right...            01/01/70 00:00      
                  Actually            01/01/70 00:00      
      Please explain            01/01/70 00:00      

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