Chapter 2: Components for Advanced Circuits #

In Chapter 1, you learned how voltage, current, and reactance interact in AC circuits. Now it’s time to meet the physical components that make those principles work—the building blocks inside every transceiver, amplifier, and power supply in your station.

As a Technician, you encountered basic components like resistors, capacitors, and diodes. Moving to General class operation, you’ll discover how these familiar parts behave differently at radio frequencies, and you’ll meet new components like MOSFETs, switching power supplies, and MMICs that enable modern radio performance. You don’t need to fully understand everything, but we will try to give you a basic foundation so you know what there is and the terms to use to find more information when it becomes more relevant.

This chapter explores the components that transform electrical theory into working radios. You’ll learn how transistors and tubes amplify signals, how power supplies convert household AC into clean DC, how digital circuits process information, and which test equipment helps you understand what’s happening in your station. We’ll also decode schematic symbols—the universal language that lets you read circuit diagrams and follow modification instructions.

These components aren’t just exam topics—they’re practical knowledge for station building and maintenance. Understanding amplifier classes helps you choose appropriate power levels for different modes. Knowing power supply operation explains that hum in your audio. Recognizing RF component behavior reveals why some parts work perfectly at audio frequencies but fail at VHF. Even if you never design circuits from scratch, this knowledge helps you make informed equipment choices, understand specifications, and troubleshoot problems intelligently.

We’ll connect each component to real amateur radio applications, showing where it appears in your equipment and why it matters for your operation. By the end of this chapter, you’ll recognize the key players that transform your ideas into RF and understand how they work together to create effective communication systems.