LED powering question
#1
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LED powering question
If I tapped into the cigarette lighter in the dash, would i be able to power 4 or 8 LEDs?
I've done this before on my PC, i have two blue LEDs in parallel off the power supply, with a 285ohm (or so) resistor on each. Just do the same thing in the car?
/twiddles thumbs
I've done this before on my PC, i have two blue LEDs in parallel off the power supply, with a 285ohm (or so) resistor on each. Just do the same thing in the car?
/twiddles thumbs
#3
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You mean like a PC rheo bus? Damnit you know i don't have a voltmeter lying around. I'd just wire them up in parallel, some resistors, and flip my switch.
#4
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Oh, for chrissake, go buy a Volt/Ohm meter!!! $10 for a cheapy at WalMart, Radio Shack, etc. And Rheostate is a fancy word for variable resistor, like the volume control **** on an (old) radio. You can use it to manually adjust the brightness of your neons, or like will said, determine the correct resistance for the amount of light you want.
#7
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Generic LED have 30 milliamp rating so for a 14.5volt system (your car) you need 470 ohms. 390 ohms will make them burn brighter but have a shorter life.
Solder the resistor is series with positive lead and cover with heat shrink tape.
To tell the diff between the positive lead and negative lead on an LED, the negative lead is on the flat side of the LED (the led only looks round, its actually a 'D' shape).
Heres a site to show you the color code for the resistors.
http://www.dannyg.com/examples/res2/resistor.htm
Solder the resistor is series with positive lead and cover with heat shrink tape.
To tell the diff between the positive lead and negative lead on an LED, the negative lead is on the flat side of the LED (the led only looks round, its actually a 'D' shape).
Heres a site to show you the color code for the resistors.
http://www.dannyg.com/examples/res2/resistor.htm
#8
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don't use a volume control for this. Volume controls have a non-linear 'Audio' Taper. Use a standard rheostat, or get a potentiometer instead, and run a jumper to turn it into a rheostat. Radio Shaq for both. Very inexpensive.
When you start running arrays of LEDs, you have to stop and think. Do you want to bias each one seperately with a resistor on each, or one resistor for the whole array?
When you start running arrays of LEDs, you have to stop and think. Do you want to bias each one seperately with a resistor on each, or one resistor for the whole array?
#9
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So if i want to do them all in parallel, i'll need around 400ohm resistance for each one? So if i'm doing 4 LEDS find a rheostat around 1.6k resistance? or for 8 do two of those, or one that does around 3.2k ohm resistance?
I'd rather use one adjustable rheostat for the whole array.
I'd rather use one adjustable rheostat for the whole array.
#10
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The cig lighter has a 10 amp fuse so you could hook up 500 standard led'* to it. average led'* need 20ma not 30ma like I stated above.
This site has what your looking for in a variable brightness led.
http://members.shaw.ca/roma/thirty-one.html
This site has what your looking for in a variable brightness led.
http://members.shaw.ca/roma/thirty-one.html