Learn Spanish (Latin America): No hay un televisor en el cuarto.

hay is a special word that means "there is" or "there are". We use it to state that something exists, especially when it is unspecific (like "a television"). You would only use está if you were talking about the location of a specific TV you already mentioned, like "the television is in the room" (el televisor está en el cuarto).

Does hay change if we want to say "there are no televisions" in the plural?

No, it stays exactly the same! One of the easiest things about hay is that it does not change for plural words. You use no hay for both "there is not" and "there are not".

Why does the negative word no go before hay?

In Spanish, to make a statement negative, the word no almost always goes directly in front of the verb (in this case, hay). You cannot put it after the verb like we do in English. So "there isn't" is always translated as no hay.

I have seen the word televisión before. What is the difference between televisión and televisor?

The word televisor refers specifically to the physical device or screen (the TV set itself) sitting in a room. The word televisión is usually used for the broadcast, the shows you watch, or the entertainment medium as a whole.