Blue LED Q's (Iceman666)

483 Views 10 Replies 3 Participants Last post by beenana, Nov 28, 2001

CorradoKidd

Discussion Starter · Nov 28, 2001

In your schematic like thing for the MFA light you used a 2000 ohm resistor in parllel with the LED. What was that for? Did you use it instead of a smaller resistor in sieries?
Good mod, I'm in the middle of doing it now. Gotta give you mad credit! http://****************.com/smile/emthup.gif

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Iceman666

· #2 · Nov 28, 2001

Re: Blue LED Q's (CorradoKidd)

Someone said thats how to do the mfa so thats how i drew it....i havent tried it yet but check the original post...I dont know what resistance the LEDs have i just checked a 12V led and got a bigger resistor(in size) with the same resistance. So i cant figure out what resistor to use Im pretty sure you can use the same resistor in the MFA as on the string though....
also do you know what resistance that resistor is....i totaly forgot

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Iceman666

· #4 · Nov 28, 2001

Re: Blue LED Q's (CorradoKidd)

you should only need one LED for the MFA and how are they more intense?? you mean brighter?
And i would recomend usng more then 3 LED's.....they might be brighter then the bulb but they have narrower feild of light

[Modified by Iceman666, 8:45 PM 11-27-2001]

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Iceman666

· #6 · Nov 28, 2001

Re: Blue LED Q's (CorradoKidd)

Ah i see...ok are you doing the LCD's with one resistor or two?
let me know how it works

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Iceman666

· #7 · Nov 28, 2001

Ok from what i have been hearing doing it with the 2 resistors will make them brighter and last longer...so im thinking you may want to do it that way
like this

[Modified by Iceman666, 9:39 PM 11-27-2001]

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Iceman666

· #8 · Nov 28, 2001

Re: Blue LED Q's (redrocketrado)

quote:[HR][/HR]what a bunch of techie dorks!

[HR][/HR]

Your point

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Iceman666

· #10 · Nov 28, 2001

Re: Blue LED Q's (beenana)

except we are dealing with 12V not 7
the 2k ohm resistor is used for current regualtion and the 750 ohm resistor is used to get the voltage across the LED down to 3.27
I just spent 30 min arguing with redDevil about this
10:06 PM 11-27-2001) RedDevil: Uaually when you get Blue LEDs they are tated at 3.4V at 20mA
V(across 750R) = (750/ (750+2000)) * 12Volts
V(across 750R) - 3.27V
So if they are paraller with 750ohm resistor they are getting 3.27Volts

(10:07 PM 11-27-2001) RedDevil: Current is limited by 2000ohm reistor
I = E/ R
current = 12/ 2000
current = 6mA perfect
I ignored 750ohm resistor because it is paralleled with LED and LEDs have very small resistance and current always flows through least resistan path.

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