Ham Amateur Radio Technician Practice Exam 2026 – The Complete All-in-One Guide to Exam Success

A Class C power stage is suitable for amplifying signals that are highly selective and require high efficiency, such as Frequency Modulation (FM) or Single Sideband (SSB). Class C amplifiers operate with a conduction angle of less than 180 degrees, which makes them ideal for amplifying signals that do not require linear output across the full waveform, like FM.

FM signals, which contain no amplitude variations and are instead defined by frequency changes, benefit from the efficiency of a Class C amplifier while still maintaining the integrity of the signal. This characteristic is particularly advantageous in terms of power consumption and heat generation, allowing for effective amplification at higher frequencies.

In contrast, Amplitude Modulation (AM) and Phase Modulation (PM) typically require linearity to accurately reproduce the modulated signal. A Class A or Class AB amplifier is generally preferred in those cases due to its ability to amplify the entire waveform linearly, ensuring that the amplitude variations and phase relationships are preserved in the output signal.

Therefore, Class C is most appropriately applied to the amplification of FM signals, as it aligns well with the requirements of high efficiency and selective frequency amplification without the need for linearity found in AM and PM applications.