PhysicsChapter 9: Electronics
Led
Introduction
LED stands for Light-Emitting Diode. An LED is a semiconductor diode that emits light when a suitable forward current passes through it. Like an ordinary diode, an LED is polarized, meaning its direction of connection matters.
Definition
Energy Conversion
An LED converts electrical energy mainly into **light**, although some energy is also transferred as heat.
Why a Resistor Is Often Used
An LED should not normally be connected directly to a source that can drive excessive current through it. A suitable **series resistor** is commonly used to limit current.
Applications
LEDs are used in: * indicator lights; * displays; lighting; traffic signals; * electronic equipment.
Exam preparation
Exam Focus
Quick revision
Revision Zone
Review the key facts, formulas and checks before you move on.Led
Sticky Notes · Quick Revision
LED
- Light-Emitting Diode
OPERATION
- Forward current → LIGHT
RESISTOR
- current limiting
60-second revision
- LED → Light-Emitting Diode.
- Forward current → light.
- Polarized → direction matters.
- Series resistor → limits current.
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