I downvoted this answer because the first half "One reason" -- "3.3V logic level" is hardly understandable for reasonably competent engineers, and certainly sibylline for most students of the level of this question. This answer may be updated by adding schematics or clearer explanations, in which case I will remove this downvote.

Reasonably competent (and even junior ranking) engineers will certainly understand the term mentioned. I don't understand why you think they won't.

Of course, since they already know this matter. My comment has to be understood as "if they were not already knowing this subject". Anyway, that's not the point. The question is of elementary level, and as such, should be answered in a more detailed way. My opinion is that most newcomers in electronics (which is the level of the question again) could not understood the first half of the answer.

coquelicot‭ in downvoting this answer you are, in effect, telling the author of the answer that his answer is worth less than no answer at all. I certainly don't think this is the case. Look at it from the perspective of the guy answering; he put some effort in to produce words that maybe could be improved but, nevertheless, as those words stand, they are still of net-use to anyone wanting this question answered. And, with you downvoting it, he is worse off than not making an answer. Now that doesn't make sense to me at all. I am questioning your motive here. You are discouraging folk from making answers.

@Andy. Not at all, as I have specified in my comment. I think this debate belongs to Meta though.