Ham Radio Extra Class Practice Test 2026 - Free Extra Class License Exam Questions and Study Guide

Using a power supply filter in amateur radio primarily serves to remove ripple voltage from the DC supply. When alternating current (AC) is converted to direct current (DC), the output typically has some residual fluctuations or "ripple" superimposed on the steady DC voltage. These ripples can result from the rectification process and can introduce noise and instability in the power supply, which can affect the performance of sensitive radio equipment.

The purpose of a power supply filter, which can be in the form of capacitors, inductors, or a combination thereof, is to smooth out these fluctuations, providing a cleaner and more stable DC voltage for the equipment. This stable voltage is crucial for the reliable operation of radios and transmitters, allowing them to function at optimal performance levels without being affected by electrical noise from the power supply.

By eliminating the ripple voltage, a power supply filter improves the overall efficiency and quality of the radio signals produced, enabling better communication and reducing the likelihood of interference.