В письме от среда, 22 августа 2018 г. 19:17:11 MSK пользователь Alessio Ciregia написал:
"a LED" or "an LED"?
It depends on how you pronounce it. For instance, there are no doubts with 'an HP printer', because 'HP' does not form a word. Apparently, LED is an acronym, so there are variants, but in written form 'an LED' is preferred.
https://www.englishforums.com/English/ALedVAnLed/kgggr/post.htm