What device converts electrical signals into radio waves?

The device that converts electrical signals into radio waves is the transmitter. A transmitter is designed to take the electrical energy generated by an audio source, such as a microphone, or a data source, and transform it into radio frequency (RF) signals that can be broadcasted through the air.

This transformation involves modulating the original signal (which can be voice, data, or music) onto a carrier wave, which is a higher frequency signal capable of traveling long distances without significant loss of quality. The transmitter accomplishes this through various modulation techniques, such as amplitude modulation (AM) or frequency modulation (FM), enabling it to effectively transmit the information over the radio spectrum.

In contrast, other options serve different functions in the communication process. For example, a receiver takes incoming radio waves and converts them back into electrical signals that can be processed, while a modulator specifically refers to the part of a transmitter that performs the modulation of the signal. A transducer generally refers to devices that convert one form of energy into another, such as converting sound waves into electrical signals, but does not apply directly to the conversion of electrical signals into radio waves. Thus, the role of the transmitter is integral to generating and sending radio waves, making it the correct choice.