Question T6C07
From subelement T6 - T6C
What is component 8 in figure T-2?
Why is this correct?
Component 8 in figure T-2 is a light emitting diode (LED). LEDs are specialized diodes that emit visible light when forward current flows through them. The schematic symbol for an LED is distinctive - it looks like a regular diode symbol (triangle pointing to a line) but with small arrows pointing away from it, representing the light being emitted. This differs from a resistor (zigzag line), inductor (coil), or regulator IC (rectangular box with pins).
Memory tip
Learn to recognize LED symbols by the light emission arrows - they always point outward from the diode symbol. This visual cue immediately distinguishes LEDs from other components in schematics, making component identification straightforward once you know this pattern.
Learn more
LEDs serve as visual indicators in amateur radio equipment, from power-on lights to SWR meters. They require forward bias to operate and have a specific forward voltage drop (typically 1.5-3V depending on color). In practical circuits, LEDs often need current-limiting resistors to prevent damage. Understanding LED operation helps when troubleshooting equipment indicators or building simple monitoring circuits for your station.
Think about it
Why do you think LEDs need current-limiting resistors in most circuits, and what would happen to an LED connected directly across a 12V power supply?