How to wire RGB led's in series ?

Discussion in 'The Projects Forum' started by korg, Aug 21, 2010.

  1. korg

    Thread Starter New Member

    Aug 21, 2010
    I'm new to electronics but learning to built LED projects through trial, error and.. reading on the net. I am making sea tides related signs for the outdoor depicting tide level at a given location and time. To make it short I build lights made of plexiglass and red and blue LED's connected in series. Depending on the tide cycle those lights will show either a uniform red or blue color. This is working fine, but I understand that I buy, drill, glue and wire double the LED's I should if only I could use in some way RGB leds instead. I have googled many hours to find out if one can wire 4 leads RGB led's in serie but didn't get anything clear about that. Anybody can help ? Thanks in advance korg
  2. retched

    AAC Fanatic!

    Dec 5, 2009
    They are just like using 3 leds.

    There is 4 leads on an RGB LED.

    Usually they share a (-) called common cathode. The other 3 leads are (+) for the Red LED, The Blue LED, and The Green LED.

    Then there are common anode. All 3 LEDs share a (+) and the other 3 leads are The R(-), G (-), and B (-).

    It really is just 3 LEDs in 1 case.

    So you can wire them however you would like. JUST LIKE stand alone LEDs.

    When you go to buy them, look at the datasheet for those PARTICULAR RGB LEDs.

    Each color will require a different resistor and have a different Vf.
  3. Markd77

    Senior Member

    Sep 7, 2009
    They won't work in series (I'm assuming they have a common pin and 3 pins for the colours) but they will work in parallel, ie all reds connected together, etc. There should be a resistor in between each colour pin and any other connection.
    (Awful picture - sorry)

  4. marshallf3

    Well-Known Member

    Jul 26, 2010
    Can you give us the part #s of the LEDs you're using and perhaps a simple circuit diagram?
  5. korg

    Thread Starter New Member

    Aug 21, 2010
    I am presently using blue leds and red leds planted separately in the plexiglass and linked in series (of 4 with a 82 ohm resistor each). My power source is 13.6 VDC and limited to 30 amps. Each of the 56 lights used in the device is composed of 56 red leds and 56 blue leds. The maximum number of LED's powered up at any given time is 3,156 That is a lot of leds and connecting them in parralel each one with its own resistor is not much interesting. If 4 leads RGB's are not possible to connect in series, isn't there some 2 leads RGB, that can be ? There I guess I would need to feed the whole bunch of series with different voltages in order to get different colors, is that so ?