L.E.D question?

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seuadr
Posts: 1
Joined: Wed Mar 12, 2008 3:47 am

L.E.D question?

Post by seuadr » Wed Mar 12, 2008 4:02 am

I've been searching the internet for information regarding L.E.D's in parallel. i have a little project i am trying, but knowning just the basics of electricity, i'm not sure exactly how i am to proceed. The project is this: i am looking to make a fuel gauge using an existing sending unit, with LED bulbs for the indicators.

now, the sending unit in question is basically a variable resistance device, the position of the float in the tank, as i understand it, equates a specific resistance in the sending unit.

the idea i have is to use LED's, in parallel that would respond to the various changes of the resistance in the sending unit.

for ease, lets say the numbers at 100 ohm's full, 50 ohm's half full, 1 ohm empty. how would i wire the leds to properly light up to indicate the level in the tank?

i was thinking possibly something like:

I (12v)
I
I
I
-----------------------------------------------(resistor1 - 100 ohm)-------(LED)
I I
--------------------(resistor2 - 50 ohm)--------(LED)-------------------
I I
--------------------(resistor3 - 1ohm)----------(LED)

with an applicable 12v resistor, to make sure that the leds aren't overloaded, as i understand most work on very low voltage and in the mili-amps.

anyone got any insight at all into the correct way to do it?
would this setup cause all three to light up at 100ohms? it feels like i am missing something painfully obvious, but i have no idea what :D

thanks in advance to anyone who can help :)

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