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???
05/21/07 07:23
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 		 #139569 - Sinking and sourcing
Responding to: ???'s previous message
Chinmay Nanda said:
I am not sure as to what you mean by "Use the micro pins to sink the 6N137 diode current

  • "sink" refers to current flowing into a pin;

  • "source" refers to current flowing out from a pin.

    Chinmay Nanda said:
    right now i am grounding the cathode

    So you need a current source to drive it; ie, you need the current to flow out from the pin, through the diode, to ground.

    You need to reverse the diode, so that the anode connects to Vcc and the current is switched to ground through the 8051's pin; ie, the 8051 pin "sinks" the current.

    Don't forget the limiting resistor, of course...

    • List of 37 messages in thread
    TopicAuthorDate
    need for isolating signals            01/01/70 00:00      
       avoiding the inverter            01/01/70 00:00      
          sinking the current            01/01/70 00:00      
             Sinking and sourcing            01/01/70 00:00      
                the bulb blinked !!!            01/01/70 00:00      
                   Don't guess!            01/01/70 00:00      
                      trnasfer char.            01/01/70 00:00      
                         Transfer characteristic            01/01/70 00:00      
       More so            01/01/70 00:00      
       I see two possibilities            01/01/70 00:00      
          accuracy            01/01/70 00:00      
             0.01% approx 14 bits            01/01/70 00:00      
             Hardly...            01/01/70 00:00      
       No need...            01/01/70 00:00      
          need to place inverter            01/01/70 00:00      
          my design            01/01/70 00:00      
             FRC?            01/01/70 00:00      
                FRC?            01/01/70 00:00      
                   or may be this......            01/01/70 00:00      
                      Not really            01/01/70 00:00      
                      Flat Ribbon Cable connector            01/01/70 00:00      
                   FRC Connector!            01/01/70 00:00      
                You don't know the Flat Ribbon Cable?            01/01/70 00:00      
                   Not by that name!            01/01/70 00:00      
             FAQ: How to post pictures?            01/01/70 00:00      
             you are grasping for straws            01/01/70 00:00      
             sure, but to what use            01/01/70 00:00      
             grounds etc            01/01/70 00:00      
                not entirely correct            01/01/70 00:00      
                   single plane            01/01/70 00:00      
                      A very well qualified layout person can do 'magic'            01/01/70 00:00      
                         but he can hardly outsmart the laws of physics            01/01/70 00:00      
                      Nevertheless, there IS a difference            01/01/70 00:00      
                         the difference            01/01/70 00:00      
                            Yes, yes, yes, but...            01/01/70 00:00      
       Aside: Other Isolation Technologies            01/01/70 00:00      
       no response            01/01/70 00:00      

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