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???
05/21/07 08:25
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 		 #139572 - Don't guess!
Responding to: ???'s previous message
I said:
Don't forget the limiting resistor, of course...

Chinmay Nanda said:
a 1k resistor would be sufficient i guess ?

Different LEDs have different current requirements and different forward voltage drops, and different applications have different requirements for how bright the LED needs to be; 1k may or may not be appropriate to your particular application - so, don't guess - work it out!

In the case of an opto-isolator, you will need to consider its transfer ratio (see the Datasheet).

It would also depend on your supply voltage - presumably 5V?

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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