Does every LED need a Resistor?

[Jbcourt]

I have 5 LEDs (LUXEON K2) with 3.6 forward voltage and 700ma. Power is coming from a 12v 600ma source.

I dont know much about electrical math, but dont i need a source with at least 18v and 700ma?

 

[Packhorse]

If you to wire all LEDs in series then yes 18v 700ma with one resistor.

You could wire them all in parallel with their own resistor each(recommended) and you would require a 3.6v 3500ma source.