While referring to any schematic involving led's we sometimes get confused with the identification of the terminals. So for identification , led’s comes with a unique way to identify its terminals as Anode or Cathode. Sometime the diode symbol creates confusion too.Identifing a LED's the cathode and anode of a led is very easy by looking inside.
LED's or Light Emitting Diode's don’t come with any labeling on it to identify Cathode(-ve,GND) or Anode(+ve).

I hope the figure below can solve this problem of identification.

Notice the picture carefully and compare it with the LED diode symbol, that should tell which one is –ve and +ve terminal. As they have to be crystall clear to glow so they don’t have any labeling on it , so the only way to know is either to test it with a multimeter or by carefully observing inside the led . The larger end inside the led is -ve and the shorter one is +ve, that is how we find out the polarity of a LED

Save this picture for reference.

NOTE: I took this picture myself from my camera , Please Do not mind for image clarity ,so i have put some labellings also .



Rakesh Mondal



Thanks for the info
<p>with new LED's you can tell by the legs; the longer leg is the Anode. Also, on some LED's the &quot;bent&quot; leg is the Anode. &quot;Bent&quot; means they put an angle in the leg near the top. </p>
Hi, a very helpful instructable for people learning electronics, but it says in the description of led polarity, that the shorter one is +v, and larger -v? Another way to identify them is by the flat side (-) or a notch. Just thought Id mention it. <br>
<p>I just learned something.... do not use super glue to hold LEDs in place. It does something to the plastic the LED is made of, and renders it ruined. </p>
You could also have mentioned that the cathode has a flat side on many round LED types.
just a shame that you hold the led the wrong way around to the circuit symbol. <br> <br>this would make this even less confusing!
Yeah i did hold the circuit in the either direction, sorry about that , But you see there is also + and - Symbol to make life easy. :) . Plus I don&rsquo;t THINK its such big issue for me being ashamed of, as you attempt to project here . anyway thanks for an attempt and comment . :) ;-)

About This Instructable




Bio: Hi my name is Rakesh Mondal , my friends call me ron vist my website for more stuffs like my post here . www.rakeshmondal.info
More by ron.rakesh.mandal:USB:- DC Motor Controller using PIC18F4550 (keyboard)Test a Stepper Motor without a MultimeterUSB Project :- USB Interface Board Using PIC18F4550
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