Which component represents the final stage of a transmitter?

The power amplifier serves as the final stage of a transmitter, playing a critical role in increasing the power level of the modulated signal before it is transmitted through the antenna. After the signal has been modulated to encode the information onto a carrier wave, the power amplifier boosts this signal to a sufficient level to ensure it can effectively propagate through the air over the desired distance. It transforms the low-level output of the preceding stages, such as the modulator, into a higher power signal suitable for transmission.

In a typical transmitter architecture, the modulator prepares the signal by combining the audio or data input with the carrier wave, but it does not increase the power significantly. The oscillator generates the carrier wave at the desired frequency but also does not amplify the signal. The tuner is responsible for selecting and filtering the desired frequency for reception, further removed from the transmission process. Hence, the power amplifier is essential for enhancing the signal strength to achieve effective communication over long distances.