What is the function of a microphone in an AM transmitter?

The function of a microphone in an AM transmitter is to convert audio frequency input into electrical energy. This process involves capturing sound waves, which are mechanical vibrations, and transforming them into an electrical signal that can be modulated for transmission.

When someone speaks or makes a sound into the microphone, it generates a varying electrical signal that mirrors the original sound wave's characteristics. This electrical signal is then used to modulate the amplitude of the radio frequency carrier wave in the AM transmitter. The modulation of the carrier wave facilitates the transmission of the audio signal over the airwaves.

Other options relate to different functions in the transmission process but do not accurately describe the microphone's role. For instance, modulating frequency signals pertains to how the audio signal is combined with the carrier wave rather than the microphone's operation. Amplifying RF signals pertains to boosting already existing RF signals, and receiving incoming radio waves is the function of a receiver rather than a transmitter.