A television transmitter is a big machine that sends TV shows and movies through the air to your home TV antenna. It works kind of like a radio station, but instead of sending out music and talking, it sends out images and sound.
To make it work, people who make TV shows and movies first send their content to the television station. Once they receive it, the station technicians put it into a fancy computer system, where they can edit it and add special effects.
When the station wants to transmit this content over the airwaves, they use a big machine called a transmitter. It's usually housed in a tall tower, so it can send the signal farther distances.
When the transmitter is turned on, it sends the TV content as special electronic waves through the air to your TV antenna. The antenna then turns those electronic waves back into images and sound that you can watch on your TV.
So, in short, the television transmitter is like a big machine that helps get all the TV shows and movies to your home TV so you can watch them.