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input switch with led in series

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patrickyeow

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hai, i am having a problem:

normally people use pullup 10kohm resistor for the input of pic

if i want connect a LED in series with the switch (as an indicator) , the 10kohm resistor will be too high... the current is too small for LED

can i just change the 10kohm resistor to 300ohm? will it damage the pic? or is there any better idea to implement this?
 

300 ohm will not damage the Pic.
Pic supply voltage?? is it the switch turn on continuously or momentarily



P.Ashok Kumar
 
the pic supply voltage is 5v (877a)... the switch will turn on continuously...until i press the switch again...

thanks for ur help :-D
 

You say that you want to connect the 300 ohm resistor and a led to the input of the pic,
there is no problem with that with the pic but depending on what drives that input you may have a problem.
The 10k is used because any device will be able to feed that input resistance with 0.5mA and change the state of the pin,
on the other hand when you connect a low value resistor then the device that drives that pin may not be able to provide all tat current.
All that being said since you are just using a switch to provide the voltage to the pin you can use any resistor value,
the switch will not have a problem driving it.

Alex
 

I am using 1k resistor for the same condition in my circuits... its working fine... Led brightness also seems good...
 

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