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Author Topic: Arduino UNO low output current on all pins?  (Read 1197 times)
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Brand new user. I really love the unit so far and have had no problem with most of the projects I have tried.
I just set up the IR library and could easily read my codes. When I tried to send them I can get no output from a Radio Shack IR led using any
resistance more than 10k. I have tried a few leds and get the same result. The output is relatively dim looking in my camera as well but it does trigger my device from about 7 feet and less. I get the same result trying to drive it from the +5 using USB power or a 12v wall wart.
Anything I am missing here? Thanks.
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Washington
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Measure the voltage before the resistor direct from the pin. It should never go below 4v.
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resistance more than 10k.
10k is too hign. Usually leds take 20 mA, may be more in impulse mode,
so base on Ohm law resistor should be:
5 V (power or digital pin) - 2 V (cross diode) / 20 mA = 150 Ohm.
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resistance more than 10k.
10k is too hign. Usually leds take 20 mA, may be more in impulse mode,
so base on Ohm law resistor should be:
5 V (power or digital pin) - 2 V (cross diode) / 20 mA = 150 Ohm.
Usually LEDS run good at about half that (10ma) but yes 10K is too high. Try 1k.
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Avoid throwing electronics out as you or someone else might need them for parts or use.
Solid state rectifiers are the only REAL rectifiers.
Resistors for LEDS!

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Quote
resistance more than 10k.
10k is too hign. Usually leds take 20 mA, may be more in impulse mode,
so base on Ohm law resistor should be:
5 V (power or digital pin) - 2 V (cross diode) / 20 mA = 150 Ohm.


LMRAO, I just realized that I was using 220"k"Ohm resistors I thought were 220 Ohm resistors. At least my math was correct on what I needed in there, even if my implementation was just a bit off.....! On the plus side I got around 50 feet using the 10 Ohm. Glad I only had time to pulse it twice very quickly,

Thanks for the quick replies.

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On the plus side I got around 50 feet using the 10 Ohm.
You can drive it with a transistor all day at that if you want.
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