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Red LED voltage seems wrong

t101

Jul 10, 2022
24
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Jul 10, 2022
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I tried testing this several times and my RED LED(the smaller one in the photo)keeps showing
~5 to 5.5volts when I isolate it. I use a standard multimeter. I am using alligator clips to anode and cathode. I was reading that the typical voltage is around 2.5 for RED. This is twice that and my bliue seems to work with 2.5 V.

What am I doing IMG_1816.jpg wrong?
 

Bluejets

Oct 5, 2014
5,882
Joined
Oct 5, 2014
Messages
5,882
Yellow wire connects one side of the LED(possibly positive), orange to the other (and possibly negative), 470r resistor seems to connect to other things.
Then again if pos rail and neg rail on the breadboard are indeed supply, what are the two cables for?
Time to supply a drawing of what you have and include power supplies used.
 
Last edited:

CircutScoper

Mar 29, 2022
290
Joined
Mar 29, 2022
Messages
290
I tried testing this several times and my RED LED(the smaller one in the photo)keeps showing
~5 to 5.5volts when I isolate it. I use a standard multimeter. I am using alligator clips to anode and cathode. I was reading that the typical voltage is around 2.5 for RED. This is twice that and my bliue seems to work with 2.5 V.

What am I doing View attachment 55723 wrong?

Probably has an internal resistor like these LEDs...

https://www.ebay.com/itm/153068193112?hash=item23a3934558:g:6XgAAOSwcfdbKaEU
 

t101

Jul 10, 2022
24
Joined
Jul 10, 2022
Messages
24
That’s iexactly right. I checked the specs and there it was: 5v red led. Curiously for what would that be used?

i
 

CircutScoper

Mar 29, 2022
290
Joined
Mar 29, 2022
Messages
290
That’s iexactly right. I checked the specs and there it was: 5v red led. Curiously for what would that be used?

i

To run the LED from 5V when the user doesn't want to bother with a separate resistor?
 
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