Sometimes when installing a new LED bulb replacement, you'll find that the bulb won't illuminate. Not to worry! Take the bulb out, rotate it, and put it back in the opposite way. LED bulbs have two sides (polarity specific) and only illuminate when installed correctly. Here's why:
LEDs, which stand for Light Emitting Diodes, are very similar to standard Diodes. A Diode allows current flow in only a single direction and is made from an anode and cathode. The current will flow inside the Diode from the positive anode to the negative cathode.
So much like the standard Diode, the Light Emitting Diode, an LED, also has a positive and negative side. If your LED bulb doesn't illuminate the first time, just give it a flip!