How do you determine if any what resistor you need for how many LEDs?.....

Thanks

 

There's a formula and it ALL depends on the specs of the LED. Like how much current it can handle and what the normal voltage drop is on it. Post that info and I'll show you what I mean.

 

Hey Frobozz, talk to him. Blackened knows his LEDs!

 

Without the LED's,

It'll be very dark and you're likely to get eaten by a grue.

"Frobozz" Haven't seen that reference in years. I think I'll go play some ZORK!!!

 

WOW, excellent trivia 86IROCZ! I haven't thought of Zork since the Commador 64 days. Everybody get out your big floppies and play!:sillylol:

 

AH, there are some fans of the famed Infocom game out there

I have'nt gotten any LEDs yet as I am just now in the planning stages and thought there might be a way to know ahead of time what and how many LEDs I would need for my project. I pick on eup today just so that I post about it and go from there....thanks.

 

Blackened: What are the specs on the LEDs you are using for your Blue Dash?

 

For 1 LED or multiple LED's wired in parallel:

+V-(V led)
Rs = ---------------
Iled

Rs = The ohms of resistance needed (the resistance value of the resistor)
+V = Input voltage (About 13.45 volts in my car)
V led = The volts the LED is rated at (mine were 5v)
I LED = The amps the LED uses (mine was .02 or 20mA)

Example:

13.45 - 5
Rs = --------------- = 422.5 Ohms
.02




For 2 LED's wired in series:


+V-(V led)
Rs = ---------------
Iled + Iled

Example:


13.45 - 5
Rs = --------------- = 211.25 Ohms
(.02 +.02)

 

spaces don't show up on this form so goto http://www.apmracing.net/old%20site/lukeS/led/LED.htm to see the formula's

 

Got another question about this and the tech article above.

If you tap off the positive and negative leads on the circut on the back of the gauge cluster, why can't the leads be dimmed?..

Is there a way to make the LEDs dim as the original bulbs did before?.....

Thanks.

 

There IS a way to dim them if you use sort of of voltage regulator circuit that's electronically controlled by the **** in the headlight switch. Too much "drama" for something you don't REALLY need. How many times to do adjust the brightness of your dash ? lol