FCC Question Pool Review

Technician Class (Element 2) • 2022-2026

Switch License

Question T6C04

From subelement T6 - T6C

T6C04T-1
Answer: C

What is component 3 in figure T-1?

AResistor
BTransistor
CLamp
DGround symbol

Why is this correct?

Component 3 in figure T-1 is a lamp. The retrieved context explains this is a simple transistor switching circuit where the transistor (component 2) acts as a switch to turn on the lamp (component 3) when positive voltage is applied. The battery (component 4) supplies current that flows through the transistor to the lamp, causing it to glow. The other components serve different functions: resistors control current flow, transistors switch or amplify, and ground symbols show circuit reference points.

Memory tip

In schematic diagrams, lamp symbols are typically drawn as circles with a filament or 'X' inside. Visual pattern recognition of standard schematic symbols becomes crucial for circuit analysis - each component has a unique standardized symbol that remains consistent across all electronic diagrams.

Learn more

This transistor switching circuit demonstrates fundamental amateur radio concepts used in keying circuits, indicator lights, and control systems. Understanding how transistors can switch loads like lamps translates directly to operating principles in transmitters, where transistors switch RF power, and in station control systems where they activate relays, indicators, and other equipment based on control signals from microprocessors or manual switches.

Think about it

Why do you think a transistor is used as a switch to control the lamp rather than connecting the lamp directly to the input voltage source?