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T6C: Circuit Diagrams – Ham Radio Technician License Study Guide

Before you can build, troubleshoot, or modify any piece of radio equipment, you need to be able to read a schematic. A schematic is a wiring diagram that uses standardized symbols to represent components and show how they connect. Every professional and amateur circuit design is communicated through schematics — learning to read them is a foundational skill.

T6C tests your ability to identify the components in three schematic diagrams that appear in the official exam (Figures T-1, T-2, and T-3). Most of the questions in this group ask you to identify a numbered component in one of those figures. This section teaches you the schematic concept and walks through each figure's numbered components so you can answer every question confidently.

Key point: T6C is heavily figure-based. Most questions ask you to identify a specific numbered component in Figure T-1, T-2, or T-3. Study the figures and the component list for each one — they will appear on your exam exactly as shown here.

In this guide:

What Is a Schematic?
Figure T-1: Components
Figure T-2: Components
Figure T-3: Components
Practice Questions

What Is a Schematic?

A schematic is an electrical wiring diagram that uses standard component symbols to show how components connect to each other. The symbols follow conventions established by engineering standards, so any engineer or technician anywhere in the world can read the same schematic. Schematics accurately represent which components are connected and how — but they do not show wire lengths, physical layout, or the actual appearance of the components.

When troubleshooting a radio, a schematic lets you trace signal paths, identify which stage is causing a problem, and verify that components are wired correctly. Being able to look at a symbol and immediately identify what it represents is the skill T6C tests.

Remember: A schematic uses standard symbols to show component connections. It accurately shows connections — not wire lengths or physical appearance.

Figure T-1

Figure T-1 shows a basic transistor switching circuit with four numbered components. Study the figure below, then memorize which number maps to which component.

Component Number	Component
1	Resistor
2	Transistor
3	Lamp
4	Battery

Figure T-1 quick reference: 1 = Resistor | 2 = Transistor | 3 = Lamp | 4 = Battery

Figure T-2

Figure T-2 shows a more complex circuit with nine numbered components. Not every number is tested — the exam asks about components 3, 4, 6, 8, and 9. Study the figure below and the table of tested components.