Ode to the Diode
First came flaming torches. Next came coal-oil lamps and electrified tungsten thread. Now we enjoy the bright cool light of high-intensity Light Emitting Diodes (LEDs). Do a Web search sometime to learn about p-n junctions, sapphire substrates and all the advanced science in these little jewels. Or forget all that and just bask in the low-heat, low-power electroluminescent glow.