# Wiring 6 LED's for better placement???

Discussion in 'The Projects Forum' started by mvp, Jan 29, 2014.

1. ### mvp Thread Starter New Member

Jan 21, 2014
9
0
I have (6) 5mm LED's, 3.6v, 20ma with 12v source
I was wanting to wire them individually, with their own resistor.
Reason to wire them individually is for better placement as i can spread them out

I dont' know how to wire these? Can this be done? I can't seem to find a diagram. With the way i want to wire them, i can't find a resistor calculator to tell me which resistor i need

This is an example of the way i want to do them, but the person who didn't would not mention how

any help would be greatly appreciated

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2. ### crutschow Expert

Mar 14, 2008
16,180
4,322
The resistor value in series for each would be (12V - 3.6V) / 20mA = 420Ω. You can use 470Ω resistors.

Jan 21, 2014
18
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4. ### mvp Thread Starter New Member

Jan 21, 2014
9
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I know about the calculator, but looking at the picture each LED is completely separated from Eachother to all be attached at some point

5. ### Metalmann Active Member

Dec 8, 2012
700
224

Should be fine, as long as you keep the polarity straight.

Cut them, and arrange however you want.

6. ### NetDoc New Member

Jan 6, 2014
22
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What's the purpose of the LEDs?

7. ### mvp Thread Starter New Member

Jan 21, 2014
9
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Polarity straight? Sorry, im a noob

Video game consoles

8. ### shteii01 AAC Fanatic!

Feb 19, 2010
3,920
600
LED has to be connected in certain way to emit light. That is what they meant by polarity. LED has two legs. Generally, one leg is longer than the other leg. The longer leg must be connected to positive terminal of the battery, shorter leg must be connected to negative terminal of the battery, then LED will light up. Connect them the other way around, and it will not light up.

If you have 9 volt battery handy, you can test each LED and mark the legs with tape or colored marker or some other way.

9. ### shteii01 AAC Fanatic!

Feb 19, 2010
3,920
600
6*3.6 volts=21.6 volts
This means you would need 21.6 volts to light up all 6 led if you connect led in series. You only have 12 volts, so series connection is not going to work.

That leaves the other solution, the parallel connection. That is what you will have to use.

The thing about parallel connection is that you are making a current divider. The current from the battery will enter the divider and it will not divide evenly. So some led will get a little more current and be brighter, some will get a little less current and be a little dimmer. What you will have to do is build the circuit, see which led are brighter, which led are dimmer, then adjust their resistors. The brighter led will need slightly larger resistors or you can go the other way, a dimmer led will need a slightly smaller resistor. Adjust one led+resistor at a time, see how it affect the other led. Overall, it is not big deal.

10. ### alexfreed Member

Oct 8, 2012
72
10
A better solution will be to have 2 circuits of 3 LEDs each in series. 3*3.6 = 10.8V
Only 12 - 10.8 = 1.2 volts to drop by a resistor of 1.2 v / 0.02A = 60 ohm.
68 is standard. The advantages are:
1. only 2 resistors needed, not 6
2. less power loss and less heat generated

No calculator needed. This is 5th grade math.