loading
IDENTIFY THE ANODE/CATHODE of LED's



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 .



THANKS FOR READING

RON

Rakesh Mondal



www.rakeshmondal.info

CATHODE AND ANODE OF LED



******************************************************************************
Thanks for the info
Ron,<br> <br> Thanks for the info. Sometimes manufacturers tend to&nbsp;<em><strong>NOT</strong></em> use industry standards and switch the Anode/Cathode leads around from the flat side&nbsp;or the leads are the same length, making it hard to decipher which is which. This will help in not blowing out unknown LED's.<br> <br> Qa
Can you tell me some of the manufacturers that do not follow the standard of using the flat side?<br><br>I have not come across this and I am really interested to know which ones.<br>
well frankly i never encountered such situation. :) But it may happen :)
well frankly i never encountered such situation. :) But it may happen :)
Can you tell me some of the manufacturers that do not follow the standard of using the flat side?<br><br>I have not come across this and I am really interested to know which ones.<br>
Quercus ,<br><br>you are right if its not some exceptional case, but most of the time this markings works just fine ( if the manufacturers follow Industry std) :) but in case if it not according to industry std , then i recommend always to use a multimeter as final touch up to ensure the polarity of led's :) <br><br><br>Thanks for the info :)<br><br><br>ron
I, personally,&nbsp;have not encountered it, but other people in the industry that I have had conversations with have told of such horrors. I remember them say that these were usually really cheap runs or some sort of special order robotic placement rolls.<br> <br> Another situation where this could come in handy is when reusing LED's from existiing projects where the &quot;ledge&quot; was ground off (I saw that a long time ago) and the leads were already trimmed.<br> <br> It is still valuable to know the construction of the LED so that if you have any question as to which lead is the&nbsp; Anode or Cathode, you can tell by looking at the inside.<br> <br> Qa
I also personally never have encountered such case :)
I also personally never have encountered such case :)
I, personally,&nbsp;have not encountered it, but other people in the industry that I have had conversations with have told of such horrors. I remember them say that these were usually really cheap runs or some sort of special order robotic placement rolls.<br> <br> Another situation where this could come in handy is when reusing LED's from existiing projects where the &quot;ledge&quot; was ground off (I saw that a long time ago) and the leads were already trimmed.<br> <br> It is still valuable to know the construction of the LED so that if you have any question as to which lead is the&nbsp; Anode or Cathode, you can tell by looking at the inside.<br> <br> Qa
Quercus ,<br><br>you are right if its not some exceptional case, but most of the time this markings works just fine ( if the manufacturers follow Industry std) :) but in case if it not according to industry std , then i recommend always to use a multimeter as final touch up to ensure the polarity of led's :) <br><br><br>Thanks for the info :)<br><br><br>ron
Ron,<br> <br> Thanks for the info. Sometimes manufacturers tend to&nbsp;<em><strong>NOT</strong></em> use industry standards and switch the Anode/Cathode leads around from the flat side&nbsp;or the leads are the same length, making it hard to decipher which is which. This will help in not blowing out unknown LED's.<br> <br> Qa
<p>thanq</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

52,744 views

4 favorites

License:

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 Multimeter USB Project :- USB Interface Board Using PIC18F4550
Add instructable to: