sorry, but i still didn't get it. when do you use Ferensehen, and when ferenseher?
"der Fernseher" is the device you watch TV on, and "das Fernsehen" refers to TV in a more abstract sense. You watch "Fernsehen" on your "Fernseher".
Mein Fernseher ist kaputt = My TV set is broken
Das Internet ist heutzutage wichtiger als das Fernsehen = These days, the Internet is more important than television
thanks for your answer, but is there anything like this in english? or only in German? i'm really trying to get the idea behind it
There is no distinction in English. Unfortunately, sometimes a language has one word for two similar meanings, while another language has two separate words for it. If you've ever studied Spanish, it's similar to how "ser" and "estar" both translate into "to be" in English, but are used for different specific situations.
There is a word 'Das Fernsehgerät' in my (not so new) dictionary, but not so sure how much frequent this word is...