# Multi-color LED

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1. Apr 1, 2016

### Hassan Raafat

Is there is a way to connect three LEDs so that there are three cases where one LED only is working in every case of the three without using micro controller ?

2. Apr 1, 2016

### cpscdave

What are the 3 cases?

3. Apr 1, 2016

### Hassan Raafat

Really I don't know what they are but I wonder it because there are two-color where are green is lighted in forward and red in reverse like that , so can I make the same for three LEDs ?

4. Apr 1, 2016

### cpscdave

I'm still not sure exactly what you are trying to accomplish.
Do you want to have 3 multicoloured LED's each displaying a different colour??

5. Apr 1, 2016

### Hassan Raafat

Not exactly , I want to have three LEDs in one circuit so each time I have a specific condition , there is only one LED working

6. Apr 1, 2016

### cpscdave

What are the conditions then??? Hard to tell you what you need to do if we don't know exactly what it is you are trying to accomplish :)

7. Apr 1, 2016

### Hassan Raafat

Not for confusing you that is an idea not a real question in the picture up I have one LED working in the forward and the other is working in reverse bias where the first became off , now the question is Can I make a circuit which have three LEDs where there is one LED working in every case , But also I can't tell you the condition because I really don't know it .

8. Apr 1, 2016

9. Apr 1, 2016

### Hassan Raafat

Please can you tell me how that works ?

10. Apr 1, 2016

### CWatters

Your circuit showing two LEDs is incomplete. Something has to make the +V node to go both +ve and -ve with respect to the earth node. That implies +ve and -ve supply voltages and a switch of some sort.

It's very easy to do what you want if you don't have any constraints. My house has at least 20 light bulbs and I can turn one (any one) on at a time without a microprocessor.....but that's because I have 20 light switches.

We can't really answer your question without knowing the constraints. Can you use three switches? One multi position rotary switch?

11. Apr 1, 2016

### Staff: Mentor

12. Apr 1, 2016

### Hassan Raafat

Thanks very much CWatters , So what you said I Can control these switches and control when to turn of the leds on , right :)

13. Apr 1, 2016

### Hassan Raafat

14. Apr 1, 2016

### CWatters

Is three LEDs enough?...

Here is a chip that can be configured to turn on 1 of 10 LEDs depending on the voltage on a single input.

Can be used in "dot" or "bar graph" modes.

15. Apr 1, 2016

### Hassan Raafat

Thanks a lot CWatters , I'll read it , you helped me a lot , Thanks again :)

16. Apr 2, 2016

### Staff: Mentor

If you were to power this two-in-one with AC you could have both LEDs glowing 'simultaneously' to give (I'm guessing) a third color: violet.
EDIT: oops, seems that the third color for a R-G led could be yellowish orange, click on customer comments in this link: http://www.allelectronics.com/make-a-store/item/led-6/bi-color-led-2-legs/1.html

Last edited: Apr 2, 2016
17. Apr 3, 2016

### Hassan Raafat

18. Apr 3, 2016

### Staff: Mentor

19. Apr 3, 2016

### Hassan Raafat

Great Video , CWatters , Really thnak you for your effort