The Right Resistor - Page 2 - Electronic Circuits Projects Diagrams Free

audioguru · 17th December 2004, 07:57 AM

The color of the LED depends on your battery voltage and the LED's voltage. Ordinary red LEDs are about 1.8V. Ordinary green LEDs are about 2.5V. Ultra-bright blue, green or white LEDs are 3V to 5V.
Someone on a post reported that he connected his LED directly to a 6V battery without a current-limiting resistor! It didn't burn out! (yet)

White LEDs shouldn't cost any more than an ultra-bright blue or green one.
The new UV LEDs cost more. I haven't seen a truly purple one yet.

Juglenaut · 17th December 2004, 12:32 PM

Diffused Leds are cheap even for blue, they really can't get to expensive for standard size and MCD. The most I have seen 20-40mcd bright translucent diffused LED go for is 20cents each.

Where is starts to get ridiculously expensive is this gasagap or something like that where the lens is clear and incredibly bright, but these LED cost just as much to make as diffused, in mass manufacturing setting. Cost varies by size, tolerance, chemicals, and process, the brightness has little to do with actual value or cost of an LED.

White is actually a LED that emits RGB at the same time, an actuall white single emitting diode is still not on the market. A purple LED would emit a mix of RB.

Unless it is a 6 volt LED that he hooked to a 6 volt battery, it still would get rather hot at the terminals.

audioguru · 17th December 2004, 03:28 PM

Quote:

Originally Posted by Juglenaut

White is actually a LED that emits RGB at the same time, an actuall white single emitting diode is still not on the market.

Nope. A white LED is a blue one with a yellowish phosphor. They don't appear very white, right? But you can buy RGB LEDs for pixel screens and stuff. I don't think they will ever have a true white LED because white is wideband and LEDs are very narrowband.

Quote:

A purple LED would emit a mix of RB.

Sorry, nope again. Purple is radiation at a frequency between blue and UV (remember learning about a rainbow?). Your eye or brain gets tricked when colours are combined. They now make LEDs operate at the extremely high frequency of UV, so purple (maybe called violet) should be easy.

Oznog · 18th December 2004, 05:26 AM

Luxeons man.
http://www.luxeonstar.com

Expensive, but they're designed for more power than you can imagine. Some take as much a 5 watts and put out the light of hundreds of normal LEDs in a pkg smaller than a pencil eraser, but require careful heatsinking since they're not a whole lot more efficient (around 15% or so) and dissipate the rest as heat. The die cannot take high temps due to poor heatsinking, it will lower the light output and degrades it over time.

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17th December 2004, 07:57 AM	(permalink)
audioguru	The color of the LED depends on your battery voltage and the LED's voltage. Ordinary red LEDs are about 1.8V. Ordinary green LEDs are about 2.5V. Ultra-bright blue, green or white LEDs are 3V to 5V. Someone on a post reported that he connected his LED directly to a 6V battery without a current-limiting resistor! It didn't burn out! (yet) White LEDs shouldn't cost any more than an ultra-bright blue or green one. The new UV LEDs cost more. I haven't seen a truly purple one yet.

17th December 2004, 12:32 PM	(permalink)
Juglenaut	Diffused Leds are cheap even for blue, they really can't get to expensive for standard size and MCD. The most I have seen 20-40mcd bright translucent diffused LED go for is 20cents each. Where is starts to get ridiculously expensive is this gasagap or something like that where the lens is clear and incredibly bright, but these LED cost just as much to make as diffused, in mass manufacturing setting. Cost varies by size, tolerance, chemicals, and process, the brightness has little to do with actual value or cost of an LED. White is actually a LED that emits RGB at the same time, an actuall white single emitting diode is still not on the market. A purple LED would emit a mix of RB. Unless it is a 6 volt LED that he hooked to a 6 volt battery, it still would get rather hot at the terminals. __________________ Your website has been blocked

18th December 2004, 05:26 AM	(permalink)
Oznog	Luxeons man. http://www.luxeonstar.com Expensive, but they're designed for more power than you can imagine. Some take as much a 5 watts and put out the light of hundreds of normal LEDs in a pkg smaller than a pencil eraser, but require careful heatsinking since they're not a whole lot more efficient (around 15% or so) and dissipate the rest as heat. The die cannot take high temps due to poor heatsinking, it will lower the light output and degrades it over time.