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???
02/16/09 18:16
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 		 #162486 - Look again - and think!
Responding to: ???'s previous message
Aamir Javaid said:
won't the pins form UDN2981 and controller be short?

Not at all!

Look again at how the resistors are connected within the SIL package:


And look again at the section of the schematic:



The box marked "10k SIP" indicates the outline of the resistor pack component: it has 9 connections - one common, and eight for the ends of the individual resistors.
The common pin is connected to +5V, and each of the other pins is connected to just one of the PA lines between the AVR and IC2.

It's just like the box marked "IC2" marks the outline of the UDN2981 and the box marked "IC1" marks the outline of the AVR.

It no more indicates that all the lines are connected together than the boxes around the other components indicate that all their pins are shorted together!

what if i use individual resistors of 10K?

Functionally, there is no difference; but there are many practical advantages:

  • Look at the size of one resistor pack relative to 8 individual resistors;
  • Consider how many individual connections you need to make with one resistor pack compared to 8 individual resistors.

    etc,...




    • 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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