What are the two ways to determine the negative leg of an led?

There are three main ways to find which end is positive and negative on LED.  First there is occasionally on the base of the LED a flat part which you would use to identify that as the negative end. Second way is to look at the length of the ends occasionally they will both be the same size, but most of the time the negative end will be shorter. And finally, LED the electrodes of the negative one is the larger of the two. 

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