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Old 17th March 2007, 14:46   #19 (permalink)
pcr
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Bog,
To avoid any confusion, you might want to include in your diagram the current limiting resistors which are part of the led pack. I assume the led pack has resistors, otherwise your going to need some spare fuses.

Itsrelfy,
Quote:
Originally Posted by itsrelfy View Post

If you have the headlights on and you open the door, youll get an even dimmer LED because you have 12V coming down one path being met by X volts coming down the other one.

The resultant voltage is 12v - Xv.
Sorry, it doesn't work like that. The diodes prevent what you describe, whichever is connected to the lower voltage will be reverse biased, effectively cutting off that path.

Assuming diode voltage drop is 0.7v.
If input A is at 12V and input B is at 11V, then the junction is at
12 - 0.7V = 11.3V.
The diode in path B is reverse biased, ie, switched off.

Last edited by pcr; 17th March 2007 at 14:54.
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