A transmitter is a device that sends out signals, like invisible messages traveling through the air. Radio stations use transmitters to broadcast music and news to your car radio. TV stations use them to send shows to your television. Your garage door opener has a tiny transmitter that sends a signal telling the door to open.

Transmitters work by converting information into electromagnetic waves that travel through space at the speed of light. When you press the talk button on a walkie-talkie, its transmitter converts your voice into radio waves that another walkie-talkie can receive. Cell phone towers use powerful transmitters to send calls and text messages to phones across town.

Scientists use transmitters to track migrating birds by attaching tiny ones to the birds' legs. Weather balloons carry transmitters that send information about temperature and air pressure back to meteorologists on the ground.

Every transmitter needs a receiver on the other end to pick up its signal and turn it back into something useful, whether that's sound, pictures, or data. Together, transmitters and receivers make wireless communication possible, connecting people and devices across distances without any wires at all.