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Topic: Led Lightning in Car (Read 1 time)previous topic - next topic

dutchronnie

Feb 15, 2012, 07:36 pm
I have a car with some led's for lightning.
I wat to change the leds into RGB leds, and control this led's with an arduino.
I have put out the existing led's and i have made a schematic of it, i will send the picture with this post.
It is an SMD led on a little PCB with 2 SMD resistors with the printing on it of 1002 = 10Kohm and 1301 = 1K3 ohm.

I don't understand the print.
one resistor is put over the positive and the negative?
Does somebody know how this works?

ArnieNFW

#1
Feb 17, 2012, 11:08 am
It's weird, but this is usually done by led's which replace car-(exterior) lightning.
In some (recent?) cars there is electronics which determine if the light is still working. This can be done by measuring the current. When the light is changed from a normal bulb (halogene) to a led, the current is drasticly reduced. So the electronics thinks the bulb is broken and warns you should replace it. To let the electronic think the bulb is okay, a resistor is put in parallel to draw more current.
Long live the green planet (I = 13.8V/1300Ohm = 10mA; P=13.8*0.01=0.15Watt).

Chagrin

#2
Feb 17, 2012, 03:15 pm
The resistor is used to emulate the higher resistance of an incandescent bulb. Specific to a turn signal, without the resistor the bulb would flash at an incorrect rate. Google for "turn signal hyperflash" for various explanations or look into how an automotive "flasher unit" works.

#3