Air Conditioned L.E.D. Displays?

[In_Correct]

I pulled in to a travel center. I walked around. I heard this sound of a beehive with bees buzzing. I looked up to see that the L.E.D. display next to the road is making that noise. So these L.E.D. Displays are air conditioned? What do these air conditioners look like.?

[Duke87]

Somehow I doubt there was an actual air conditioner involved. There would not logically be any need for one.

It is possible that the display featured a fan to vent heat generated by its internal workings, and you were hearing the fan, though even this would be unusual.

More likely if you were hearing buzzing, the sound was being generated by the driver that converts AC to DC (LEDs run on DC power, so anything LED that is connected to the electric grid will have one) - it normally shouldn't buzz, though, this indicates it's going bad.

Alternatively, the sound you were hearing may have been coming from a transformer - those naturally vibrate at 120 Hz just because of how they work.

[roadman]

Actually, the fans are there to keep the internal components cool when the equipment warms up due to outside temperature, and not because of the heat the components themselves generate.  There are sensors on the case that regulate when the fans will activate.