Sitcom

Sitcoms or situation comedies are a very popular genre of television serials. It appeared in the beginning of the 20 century and quickly gained wide audience. Situation comedies are characterized by the permanent presence of certain characters (unlike soap operas, where characters may be changed with the development of each storyline) living in one place and related to each other in one way or another. And, of course, the word "comedy" supposes that such shows have to be funny (not every show can meet that condition though). Another feature of comedy shows is that each episode has its own finished plot, although some of them may have some features of a soap opera with long storylines developing together with short episodic stories (for example "Friends"). As a rule, sitcoms are being shot in front of an audience, that's why off-screen laughter is characteristic for them (low-budget sitcoms use recorded laughter though). Their plots may be different, but in most cases they are simplified versions of life with an emphasis on funny situations (for example making main characters look stupid etc.).
Some of the sitcoms are based on contrast. But, unlike the classic contrast in usual soap operas (the evil and the good), the contrast in situation comedies may not have any certain boundaries. The contrast may, for example, be based on different world-views of parents and their children, different tempers between a wife and a husband etc. The contrast creates conflict situations that develop into absurdity which is usual for such type of TV shows.