Lecture on LEDs (Light Emitting Diodes)

Introduction to LEDs

• Definition: LED stands for Light Emitting Diode.
• Semiconductor material: Core of LED is a piece of semiconductor with impurities on each side.
• Electron movement: Electricity flow causes electrons to move and release light due to energy state changes.

Light Emission and Color

• Narrow wavelength: LEDs emit a single color determined by semiconductor materials.
• Color spectrum: Colors from red to blue and beyond visible spectrum (infrared, ultraviolet).
• White LEDs: No true white LEDs due to narrow wavelength.
  • White light creation: Uses blue emitter with phosphor coating to mimic white light.
  • Color Rendering Index (CRI): High-quality phosphor used for better color accuracy.
  • Color Temperature: LEDs can mimic various lighting conditions (e.g., daylight at 5600K, incandescent at 2700K).

Efficiency and Heat Management

• Efficiency: LEDs are efficient because they emit light directly without producing excess heat.
• Heat issues: High-powered LEDs still generate heat; solutions include heat sinks and good thermal management.

LED Configurations and Applications

• Reflectors and Lenses: Used for long light throw capabilities.
• COB LEDs:
  • Chip on Board (COB): Multiple emitters grouped for high brightness.
  • Powerful COBs: Larger and brighter, can output tens of thousands of lumens.

Powering LEDs

• Current Sensitivity: LEDs need controlled power to prevent damage.
• Power Limitation: Low power LEDs use resistors; high-power needs LED drivers or voltage regulators.
• DIY Projects: Use voltage regulators for constant current control.

Building a Custom LED System

• Components Needed:
  • COB LED
  • Heatsink (from old computer parts)
  • USB type-C battery bank
  • Voltage regulator
• Assembly Process:
  • Soldering wires to LED
  • Using thermally conductive glue for mounting
  • Adjusting voltage and current for LED

Advanced LED Types

• Fun Filaments: Mimic Edison bulbs, used for decorative purposes.
• RGB LEDs: Combine red, green, and blue emitters for a variety of colors.

Conclusion

• Applications: LEDs are versatile for various lighting needs, from environment lighting to photography.
• Future Plans: Upcoming projects include mimicking natural sunlight.

Additional Information

• Sponsor Message: Blinkist provides summaries of non-fiction books for efficient learning.
• DIY Tips: Experimenting with LEDs can lead to creative and practical lighting solutions.