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??? Dose Any Body Know What Kind Of Resistors To Use On a LED I Got Some LEDs From Old Circut Bouds and I've Heard That Too Much Power Can Dammage A Led And You Need A Resistor But I don't know what resistor to use ??? :-\ ::)

Ps Can You Guys Tell Me What Colors Are On The Resistors[move] ??? ??? ???[/move]

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for 9 volts use 390 ohms resister for the 5mm led if you use 12 volts use 500 ohms and for 24 volts i think it is use 1.2k at 1/4 watt, you can allso download the electronics calculators , like the led sieries resistor calculator and other calculators like the zener diode calculator and resister devider calculator , there is a link somewhere in the forums that will take you to the site that has these downloads, its called electronics 2000

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Hi Cody,
LEDs have a very low voltage rating. If connected across a voltage source without a current limiting resistor in series with them, they will instantly burn-out.
The current-limiting resistor's value is calculated using Ohm's Law. But first you need to know the voltage rating of the LED, which depends on its chemistry and colour. I could detail most LEDs voltage ratings but they are listed at many other places and on their datasheets.

Steven's quoted resistors will work fine with all LEDs. They limit the current to a safe amount. Their values can be reduced when calculated properly for use with higher-voltage LEDs at high brightness requirements.
However, Steven's suggestion of only a 1/4W resistor with 24V will make the resistor very hot and burn it out. A 1W resistor is recommended.

I learned the colours of the rainbow when I was a little kid: Roy G. Biv, where Indigo and Violet look like purple. Resistor values are in the same order and Red is 2, Orange is 3, etc. Purple is 7. In addition to the rainbow, Grey is 8, White is 9 and Black is 0. You will quickly learn resistor values if you measure many with an ohm-meter.

How did you make those question-heads run around? That's cool. See, I copied yours and it doesn't move.


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Thanks Ante,
I fixed it. I thought the sentence looked bad but I was so excited that it moves I wasn't concentrating. Double negatives should never be used. Anglais?

I just picked up a brand new but surplus 5V/2A switching wall wart that weighs almost nothing (same as its output cord) and measures 7cmL X 3cmW x 4.8cmD. It costed $3.15US. A good deal.
It's labeled: Output 3-36VDC, 15W Max, Preset to 5.0VDC. I'll cut it open and put a knob on its control.

[move] ;D;D;D ;D;D;D ;D;D;D ;D;D;D ;D;D;D ;D;D;D[/move]

I also picked up a heavy transformer'd wall wart that's 15VDC/600mA, for $2.35US. Another good deal.

You should see my place. I've got blinking and dimming LED projects everywhere!

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:)leds i used them for fuses in an old capacitor discharge circuit and with a pulse generater and a long board with diodes and 63 volts 10uf electros as a voltage multiplier after the m2851 transformer in reverse mode i measured 500 volts but i dident know the current, but useing the led as a fuse for that voltage channelling fuse should of been impossible but it worked this wierd circuit setup i used a triac only 2 legs of it i even used the hv output of 500volts at low current i geuss it was to power the capacitor discharge circuit and the led used as a fuse was a bit amazeing and the led dident get hot nor did it blow tp peaces it just qiuetly blew inside if i accidently short out anything

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